Part Two:
The Battles for Midway and the Aleutians

Japanese Strategy

The successful record of the Imperial Japanese Combined Fleet against the combined American, British, and Dutch fleets following Pearl Harbor must have mitigated Japanese disappointment that in the attack on 7 December 1941 the Striking Force failed to sink or damage a single U.S. carrier. It was primarily the objective of drawing out destroying the U.S. carriers that prompted Admiral Isoroku Yamamoto, Commander in Chief of the Combined Fleet (CINC Combined), to revive an earlier plan for the capture of Midway and resubmit it to the Navy General and Imperial General Staffs.1

In Yamamoto's view, possession of this island base, along with Wake and the Marcus Islands, allowed Japan to pursue its Asian policies behind an impregnable eastern shield. General Staff strategists disagreed with Yamamoto and his Combined Fleet staff. They chose instead to pursue a more conservative strategy. They reasoned that, in the long run, Japan could not hope to defend a chain of isolated bases far to the east of the Japanese homeland. They were also convinced that the United States would never launch an offensive far to the west of an American base.

In Japan in April 1942, however, it was hard to conceive of a military failure in the near future. Japanese naval superiority over the United States in the Pacific was staggering. In carriers alone it was nearly three to one (11-4 overall and 10-3, in May 1942). In battleships, those paragons of seapower in 1942, the U.S. losses at Pearl Harbor made the disparity even more one sided (11-0).2 Until early May 1942, despite the efforts of U.S. submariners, Japanese naval losses, particularly in surface forces, were virtually negligible, and their gains so immense that to the Combined Fleet Staff the task of creating an eastern shield promised to be almost effortless if undertaken at once.

This combination of success in battle and overwhelming physical superiority greatly emboldened planners on the Combined Fleet Staff who could see the weaknesses in the U.S. Pacific Fleet. They also knew that this weakness was only temporary, particularly since passage of the "Two Ocean Navy" bill by the U.S. Congress in July 1940. On 7 December 1941, the U.S. was building 15 battleships, 11 carriers, 54 cruisers, 191 destroyers, and 73 submarines.3 Because of the number of ships under construction, the Japanese knew that the day was fast approaching when the United States would possess the capability to mount overpowering naval campaigns in the western Pacific. They had to engage the U.S. Pacific Fleet in a climactic, victorious showdown as early in 1942 as possible.4

The naval staff under Rear Admiral Osami Nagano raised objections to the plans implementing Admiral Yamamoto's Midway and Aleutians strategy. Their criticism concerned problems of logistics in maintaining and defending such distant bases. Citing


as counter arguments the vulnerable northeastern approaches to Japan, the Combined Fleet Staff under Rear Admiral Matome Ugaki methodically overrode all objections one by one.5 Undoubtedly sharing the misgivings of their colleagues on the Naval General Staff, but after much deliberation, the Imperial General Staff reluctantly agreed on 16 April 1942 that this operation could occur after Fiji and Samoa had been secured.6

Midway -- Areas of Operation

On 18 April, two short days after the Japanese had decided to attack Midway, Lieutenant Colonel James Doolittle, U.S. Army Air Corps, led a courageous band of American airmen from the deck of the carrier Hornet in a spectacular air strike against several cities in the Japanese homeland. Though Japanese submarines detected its presence northwest of Hawaii on 10 April and Japanese radio intelligence reported its probable intentions on the 14th, the American two-carrier task force enjoyed the element of complete surprise. By launching land-based bombers instead of conventional carrier


Lieutenant Colonel James Doolittle on board USS Hornet.


bombers, the Americans effectively disrupted the timing of Japanese defenses and eliminated in a single stroke all objections to Japan's concept of extending the first line of defense as far to the east as possible and as soon as possible.7 By the end of April, the Japanese approved a new Midway-Aleutians timetable moving this operation ahead of Fiji/Samoa. The Imperial General Staff also chose early June for the operation to avoid disrupting the Ocean/Nauru operations in mid-May.8

The centerpiece of their Midway plan was an armed feint toward Alaska followed by the assault on Midway. When the U.S. Pacific Fleet responded to the assault on Midway, another Japanese task force under Admiral Yamamoto himself, lurking unseen to the West of the Midway Strike Force, would fall upon and destroy the unsuspecting Americans. If successful, the plan would effectively eliminate the U.S. Pacific Fleet for at least a year and place the eastern most Japanese base on the 180th parallel. There it would represent a positive threat to Hawaii and an outpost integrated with Wake and the Marcus Islands from which ample warning of any future threat by the U.S. would come. The occupation of Adak, Kiska, and Attu was viewed as a temporary measure providing protection of the northern flank of the Midway forces and a temporary barrier for any immediate U.S. strikes against the Japanese homeland. The Alaskan operation would also provide a lift to Japanese civilian morale and act as an irritant to U.S. military and political decision makers. When the Japanese began to implement their plans, using extensive war games and communications exercises, vital naval radio communications became virtual mirrors of their intentions to those who knew how to interpret them.

Japanese Preparations

The Japanese Combined Fleet's ambitious plan for the seizure of Midway and the Aleutians and for an epic naval battle with the U.S. Pacific Fleet involved a massive force consisting of warships, transports, auxiliaries, and air strength. The two operations, Alaska and Midway, required the Combined Fleet to supply over 200 ships, including 8 carriers, 11 battleships, 22 cruisers, 65 destroyers, 21 submarines and approximately 700 aircraft.9 For the first time since the war began, Admiral Yamamoto, who also commanded the First Fleet, planned to direct operations from his flagship, the battleship Yamato. From this vantage point he controlled the timing of the final trap, which, when sprung, would complete the task begun at Pearl Harbor. He began to concentrate the naval elements intended for the Midway campaign in their home ports on the Japanese Inland Sea and elsewhere in Japan. His preparations were interrupted momentarily by the Doolittle raid and the subsequent attempts to find the American carriers. When the search ended, the First Fleet prepared to host a four-day series of war games aboard the super-battleship Yamato at its anchorage in the harbor of Hashirajima.10


The games took as their starting point a prospective invasion of Midway and the Aleutian Islands. At the conclusion of the games on 5 May 1942, Imperial General Headquarters issued Navy Order No. 18, which directed Admiral Yamamoto to "carry out the occupation of Midway Island and key points in the western Aleutians in cooperation with the army."11

COMINT Reflections of Japanese Preparations for Midway and the Aleutians

The radio communications necessary to assemble, command, and control the huge forces being gathered to implement the Combined Fleet's plans did not escape the notice of U.S. Navy communications analysts, who were usually but not always able to distinguish between Moresby- and Midway-related activities. Using only the outward forms of radio activity as they had before the war began, the U.S. Navy's traffic analysts slowly discovered and disclosed Japanese intentions in the northern Pacific. When the U.S. Navy's cryptanalysts finally broke the seal of the Japanese Navy's General-Purpose Code (JN 25), they found in messages exchanged in radio communications vital details of how the Japanese Navy intended to implement its strategy in this part of the Pacific. Together, U.S. Navy communications analysts, as we shall see, provided key pieces of information for U.S. strategists concerning Japanese plans, intentions, and force levels at Midway by following Japanese fleet movements and war games in detail.

Evidence of a possible Japanese intent to extend their defensive perimeter beyond the Wake- Marshalls-Gilberts line began to appear in naval communications in early 1942. The first indication that the Japanese once again had hostile intentions east of the Marshalls occurred on 5 March, Japan time, when the Fourth Fleet under Vice Admiral Shigeyoshi Inouye launched a minor armed reconnaissance over Oahu. Using seaplanes from the Marshalls refueled on the return leg by a submarine at French Frigate Shoals about 500 miles west of Oahu, the Japanese called this project either their "K Campaign" or "Operation K." It was not intended as a prelude to invasion; however, this feeble if imaginative operation actually supported an American misconception that Hawaii was still a potential Japanese objective.

The limited evidence developed by HYPO concerning the intent behind the "K Campaign" was contained in three reports originated by [LCDR Edwin T.] Layton and [LCDR Joseph J.] Rochefort on 2, 4, and 5 March 1942. (The attack occurred on the night of 4/5 March, Hawaii time.)12 The first, written by Layton, said the Japanese were preparing an offensive in the Hawaiian area during the week of 5 to 12 March. The last, written by Rochefort, correlated submarine activity at French Frigate Shoals with the bombing of Oahu, concluding that the submarine refueled the aircraft. On 11 March both Rochefort and Layton warned that the real threat to the U.S. Pacific Fleet in the central and northern Pacific lay in the Japanese buildup in ground-based aircraft in the Marshall Islands and the Mandates. All carrier raids -- and, as it turned out, all pursuing U.S. warships -- were forced to conduct their activities with one eye on the range of those aircraft.13


During March and April, the Japanese shifted land-based air units and equipment destined for the occupation and defense of Midway from their homeland bases to the Marshalls and the Mandates. Through analysis of communications activity and exploitation of intercepted messages, navy communications analysts detected and reported daily the Japanese activities, frequently warning that the Japanese were planning an attack on Midway. These warnings were not universally accepted. Evaluations of Japanese naval capabilities by senior U.S. Navy officials in Washington were sometimes perilously inaccurate. For example, in defiance of any realistic appraisal of Japanese capabilities, an all-out attack on the West Coast in 1942 was expected at any time.14

One of the Japanese undertakings communications analysts and some senior naval officials in Washington found most difficult to understand was the most modest: a reprise of the first K Campaign. References to preparations for a second K Campaign began to appear in Japanese Navy communications in May 1942. Communications analysts in Melbourne and Hawaii quickly and consistently agreed in their interpretation of the accumulating evidence that, from the outset, the Japanese intended to attempt another seaplane reconnaissance of Oahu. On 6 May, HYPO explained that K, or King, was an abbreviation for AK, the Japanese geographic designator that stood for Pearl Harbor.15

Message volume generated by preparations for this operation was much higher than for the earlier campaign, and there were occasional foul-ups. On 14 May, for example, Layton confused the K Campaign preparations with those of Midway and reported that the second K Campaign was a name the Japanese had assigned to their assembling Strike Forces.16 On 15 May, NEGAT mistakenly warned the War Plans staff in Washington (Admiral Richmond K. Turner was head of War Plans at the time) that the K Campaign was to be a large-scale attack on Hawaii.17 Fortunately, the second K Campaign never materialized. Despite the momentary breakdown in understanding on his staff, Admiral [Chester W.] Nimitz agreed with his intelligence advisors in HYPO and Melbourne concerning the true nature of the Japanese operation and took appropriate action to frustrate Japanese plans.

On 13 May, Admiral Nimitz ordered the commander of the Hawaiian Sea Frontier (COMHAWSEAFRON) to provide surface patrols of the French Frigate Shoals area.18 This order proved to be decisive in thwarting Japanese designs for Operation K. Later that month, when the Japanese submarine captain prepared to take up his position for refueling the Japanese seaplanes, he found a U.S. naval vessel anchored in the lagoon he intended to use. Returning after two days, he found the vessel still there. Unable to fulfill his mission, he was ordered to withdraw, and Operation K was scrubbed,19 an unsuspecting victim of the U.S. Navy's vigilant COMINT effort.


The vigilance of communications analysts also paid handsome dividends in their early reports of Japanese preparations to attack Midway and the Aleutian Islands. The reports revealed how thoroughly and completely the Japanese Navy relied on its communications to fulfill its objectives. Warnings of Japanese intentions to expand their defensive perimeter eastward in the direction of Midway began to appear in COMINT reports even before the JN 25 messages were fully readable. The digraph AF, from the "A" or American portion of the Japanese geographic designator system, appeared in partially readable messages as early as 4 March 1942. On 13 March, U.S. cryptanalysts broke JN 25, and Corregidor firmly identified AF as Midway.20 AF appeared again on 17 and 24 April in messages translated by Melbourne and Washington, respectively.21 Not surprisingly, since they probably shared the same database, Melbourne agreed with the earlier identification by Corregidor. The Corregidor center was evacuated to Melbourne in three increments: 5 February, 16 March, and 6 April 1942.22 OP-20-G agreed with the AF/Midway association but as a communications designator not as a geographic designator, a troublesome distinction when it surfaced later.23

Indications of hostile Japanese intentions toward Alaska began to appear in COMINT reports published in late April 1942. A warning came from Melbourne on 27 April 1942, when the station published a translation of a message from Admiral Nobutake Kondo, CINC 2. In it he requested charts of the area 50-61 degrees north, 140-165 degrees east, an area encompassing the region from the Gulf of Alaska to Vancouver, British Columbia. On the same day HYPO also published a translated Japanese Navy message concerning the number of planes in "AOE" and "KCN," which were identified as Dutch Harbor and Kodiak Island, respectively.24 In the face of such compelling evidence, although the scope of the Japanese effort remained temporarily hidden, Layton advised Admiral Nimitz and officials in Washington that a Japanese offensive "in the Aleutian chain seems possible in late May.25

Beginning on 1 May, Japanese Navy communications activity from the vicinity of Japan began to increase visibly. Navy analysts soon realized that the additional intercept reflected naval exercises conducted in preparation for both the Midway and Aleutian operations. By studying the form and the substance of these communications, navy analysts obtained an abundance of detail about Japanese plans and the magnitude of the forces to be arrayed against each objective. Their reports enabled Admiral Nimitz to counter the Japanese preparations in his own plans, particularly those for the defense of Midway.

As Japanese ships began to depart their anchorages, communications intelligence provided information on their future dispositions. Some movements probably coincided with the initial Midway Games conferences held on board the Yamato and the exercises that followed, while others were only forecasts. Although unaware of the initial conferences aboard the Yamato, the centers at Melbourne and Hawaii reported the pairing of CarDivs 1 and 2 for exercise activity in home waters between 3 and 12 May and published the relevant translations. In addition, HYPO provided a translation on 7 May


1942, containing the complete agenda for an "aviation conference" on 16 May called by Vice Admiral Nagumo, who by that date would be anchored in the harbor at Kagoshima.

Vice Admiral Chuichi Nagumo

According to the translation, this was a conference not on strategy but on tactics to be employed in an amphibious assault. It included items such as "the battle for air superiority"; "the study of organizations for use in dive bombing, torpedo attacks, bombing and strafing in the battle for wiping out local resistance"; and " . . . organization of air fleet aviation and fleet air units ashore and their training." This revealing message not only provided a warning about the type of battle to expect, but it also gave CINCPAC planners excellent insight in formulating their plans to defend Midway. As important as this information was to Admiral Nimitz, it concerned only the air arm of the assault force and none of the surface elements. Information concerning important units such as the Second Fleet was still needed.

During the last days of April and into early May 1942, the status of Admiral Kondo's Second Fleet became clouded with uncertainty. Since the Second Fleet was the strongest surface force in the entire Combined Fleet, it was vital that Admiral Nimitz know the intentions and whereabouts of Admiral Kondo at all times. Several factors contributed to the temporary disappearance of this important fleet: its past involvement in the search for the Hornet and the Enterprise task forces between 18 and 25 April; its association with the "Alaskan Charts message" on the 27th; its location in the Northern Area from shortly after the 26th, when it was close to Soviet waters; and the introduction of a new call-sign system throughout the fleet. The northern flavor of this evidence and a period of radio silence observed after 27 April strongly implied to communications analysts in the Pacific that the Second Fleet had returned to home waters. This conclusion may explain why the subject of this fleet did not arise in the daily bulletins. Since U.S. analysts did not actually know its whereabouts, however, internal reports also suggested that the fleet had an interest in further offensive action "possibly in the Aleutians."26


On 2 May, to clarify the reports from Australia and Hawaii, communications associated with the Second Fleet yielded information that contradicted Melbourne's tentative conclusions of the day before. A translation published by OP-20-G suggested for the first time that Admiral Kondo had interests beyond the northern area that involved the Midway Strike Force.27 A message originated by his Chief of Staff, Rear Admiral Caustic Shiraishi,28 concerned the post-Midway Japanese plan to assemble portions of the Midway Strike and Occupation forces at Truk. Shiraishi advised the 5th Base Force, Saipan, which probably had a detachment at Truk, that an "A" Force and a Striking Force would be in Truk after 20 June. Significantly, the message was also addressed to COS 1st Air Fleet, Rear Admiral Ryunosuke Kusaka, and COS 4. Fifth Base Force was subordinate to the Fourth Fleet. Saipan, with its excellent airfields and harbors, was an important base for Admiral Inouye's Fourth Fleet.

Undoubtedly related to the 2 May message from Admiral Shiraishi was another message intercepted two days later. It contained an undated anchorage assignment at Truk for units of the Midway Strike Force and the Second Fleet. It was sent to Admiral Nagumo's 1st Air Fleet by an unidentified originator. Together the two messages created confusion in Washington and Hawaii. To NEGAT analysts, they suggested the existence of more than one Japanese Striking Force in the central Pacific. If this were true, it would be a matter of grave concern to the U.S. Pacific Fleet.29 Washington did not immediately resolve this issue to its own satisfaction, but NEGAT warned that their rendezvous possibly heralded a "second phase to Midway, possibly involving another [sic] attempt to invade Hawaii."

Here, rather uncomfortably, matters stood until 8 May 1942, when HYPO correctly associated 1st Air Fleet elements with several important 2d Fleet elements, e.g., BatDiv 3 and CruDiv 8. HYPO warned correctly of the creation of a possible Strike Force organization under Vice Admiral Chuichi Nagumo, CINC 1st Air Fleet. According to HYPO's analysis, it consisted of the four carriers of CarDivs 1 and 2, CruDiv 8, two battleships from BatDiv 3, and other 2d Fleet elements.30 All of these conclusions were correct, and such early recognition of the Midway Striking Force gave a major advantage to the planners in the U.S. Pacific Fleet.

Reinforcing the discovery by HYPO of a new Japanese Strike Force, on 9 May Melbourne intercepted and translated "1st Air Fleet Striking Force order No. 6." This message to the "Commander Destroyer Striking Force" ordered destroyer screens for a movement of many of the capital ships in the Striking Force. It confirmed beyond a doubt that the Japanese Navy had in fact created a new carrier Striking Force. A subsequent translation on the same day revealed that a major movement of this force was to occur on 21 May, when its battleships and carriers were to depart Sasebo.31 Layton and Rochefort confidently advised Admiral Nimitz that a combined 2d Fleet, 1st Air Fleet operation could be expected at the end of May.32

This advice arrived in the two major headquarters to surprisingly different receptions. On the 12th both King and Nimitz recorded their views on the various scenarios reflected in Japanese communications. Nimitz stated in his Command Summary that the Japanese


would "attack Moresby when reinforced; occupy Ocean and Nauru starting 18 May (local); commence an operation May 21 with a force of about 3 BB, 2-4 CV and usual forces. The objective may be Oahu." Admiral King conversely published an assessment filled with concern for the safety of Admiral Halsey's Task Force 16, which at this time theoretically was within range of Admiral Inouye's air patrols. In addition to a recommendation that Halsey be withdrawn from the forward area at once, King also recommended that the air groups of both Task Forces 16 and 17 be operated from shore-based facilities east of Australia and in Hawaii.33 Both messages revealed a serious level of confusion about Japanese intentions.

Japanese messages translated on the 13th obligingly provided clarification of Japanese intentions in the Hawaiian and Aleutian Islands and reduced American anxiety concerning a possible Japanese threat to the West Coast. The originator of this message was unknown, but its contents left little to the imagination of American naval officials:

From U/I: Request this ship be resupplied with the following charts: (Send them to the 4th Fleet at Saipan to hold for us.) 2002, 2011, 2012, 2013, 2015, 2016, 2018, 2020.34

OP-20-G quickly supplied the identities for all charts except 2002, which was probably a garble:

2011-Niihau to Oahu; 2012-Oahu to Hawaii; 2013-Hawaii; 2015-Pearl Harbor; 2016-Oahu; 2018-Seward Anchorage and Wells Bay; 2020-Western Hawaii Group, Chart 2.35

A "2nd Fleet Operations Order No. 22," intercepted and translated by both Hawaii and Melbourne, provided strong evidence that Admiral Kondo's Second Fleet also had interests in the Marianas. The translation outlined control of shore-based 11th Air Fleet units proceeding "to the Saipan-Guam area for the forthcoming campaign."36

These translations produced an immediate change in the highly fluid views of Admiral King. On 14 May Admiral King revised his earlier and vastly different estimate of the situation published on 12 May and, for the second time, directed Admiral Nimitz to declare a state of "Fleet Opposed Invasion." (A similar order was published in March 1942 in reaction to the first K Campaign.) Rather than again expressing his concern for the aircraft and ships of Task Forces 16 and 17 and calling for their effective dismantling, King cited four "possible future enemy actions now in preparation: 1) Attack Midway-Oahu line in force first week June; 2) Simultaneously attack the Aleutian Chain; 3) Occupy Ocean and Nauru about 17 May; 4) Reinforce New Britain/New Guinea and strike southeast any time between 25 May and 15 June.37

When on the 14th Layton notified Admiral Nimitz that "the forces to be under the command of CINC 2 have begun to assemble in the vicinity of Saipan," he also mistakenly associated the activity with the K Campaign.38 To Nimitz, whose view of the situation was not obscured by the confusion over the K campaign, this report meant that even an impending threat to Oahu, however ill-defined and that he had posed on the 12th, was still at a relatively safe distance.39 Admiral Nimitz did, however, implement the King directive


and declared a state of "Fleet Opposed Invasion" for the Hawaiian and Aleutian Islands, including Midway.40

Just as in March 1942, when Washington reacted so strongly to the first Japanese K Campaign, publication of this order gave Nimitz complete control of all military forces, including B17s, in the Hawaiian Islands. General Delos C. Emmons, Commander, U.S. Army Hawaii, who was not privy to Admiral Nimitz's intelligence, challenged Admiral Nimitz's decision to defend Midway rather than Oahu. To placate General Emmons, Admiral Nimitz assigned Captain James M. Steele, USN, to reassess all the supporting information developed by Rochefort and Layton and to "present the devil's argument" at every opportunity.41 For a time Captain Steele became a constant presence with Layton, but Nimitz was never presented with sufficient reason to change his decision.42 To the very end, however, General Emmons remained firm in his doubts despite the fact that Admiral Nimitz began to supply him with intelligence reports. On 25 May Emmons warned Nimitz that he was placing too much reliance on reports of Japanese intentions. Instead, he advised Nimitz to base his estimates on Japanese capabilities and look for the land-based aircraft in the Marianas to attack Oahu.43 After the battle General Emmons apologized for doubting Nimitz' strategy and presented a "jeroboam" of cold champagne to him and his staff.44

By 16 May both Admiral Nimitz and Admiral King were in almost total agreement concerning Japanese intentions toward Midway and the Aleutians.45 The views shared by Nimitz and King were in sharp contrast to the confusion that reigned between OP-20-G and the COMINCH War Plans Staff under Admiral Richmond K. Turner. According to their internal correspondence and a 15 May message to CINCPAC, apparently originated by Turner, analysts in Washington believed that the strong enemy force deploying from Japan the last week in May 1942 was related to an offensive against northeast Australia, New Caledonia, and Fiji, starting between 15 and 20 June.46

The confusion in OP-20-G and the War Plans Staff revealed by the 15 May message from Admiral King's headquarters was not limited to overlooking or ignoring the Japanese plans for Midway. According to the message for which a source within the generic address "COMINCH" cannot be identified, forces from the northern and the central Pacific campaigns were mistakenly mixed together. The message also incorrectly reported the existence of a second Strike Force by associating a force assembling in Saipan and scheduled to leave on 24 May with the carrier element of the Northern Strike Force. Its objective, according to Washington, was possibly to eliminate Midway or to divert U.S. forces from the South Pacific and Alaska. The same message noted that Howland and Baker might be objectives rather than Ocean and Nauru.47 Reacting to the possible presence of two Japanese Striking Forces somewhere between Japan and Truk, Admiral King at this point prudently recalled all U.S. shipping to Pearl Harbor.48

On 16 May, reacting to Japanese Fourth Fleet communications activity reported by the Pacific centers, Admiral Nimitz advised CTF 16 that the Japanese had "indefinitely postponed" their plan to attack Ocean and Nauru, and he ordered Halsey to return to Hawaii.49 He also published his adjusted assessment of Japanese intentions,50 concluding


that in the central and northern Pacific the Japanese would attack Midway and raid Oahu the first part of June. In addition, he speculated that the seaplane bombing raid of Oahu might be delayed until the full moon at the end of the month (probably meaning the end of May). He also stated that "unless the enemy is using radio deception on a grand scale, we have a fairly good idea of his intentions."51

Aware from the behavior of the Fourth Fleet that the Japanese had not given up on Moresby, Admiral Nimitz provided Washington his full appreciation of current Japanese intentions throughout the Pacific: Present indications [are] that there may well be three separate and possibly simultaneous enemy offensives. One involving cruisers and carriers against the Aleutians, probably Dutch Harbor. Second against Port Moresby involving present forces that area. Probably reinforced third against Midway for which it is believed the enemies (sic) main striking force will be employed.

The message went on to indicate that his appreciation for the timing was uncertain but that the presence of Halsey in the south resulted in postponement of the Ocean and Nauru operations.52

On 17 May Admiral King published a remarkably accurate assessment of the enemy's strength for the Midway and Aleutians operations: Midway attack force -- four fast BB in BatDiv 3, CruDivs 4 and 8, CarDivs 1 and 2 plus possibly Zuikaku, at least two DesRons and a landing force; Unalaska attack force -- CruDiv 7, CarDiv 3 (Ryujo and Hosho), at least two DesRons and troops. His estimate covered only those elements already identified in communications. It did not account for all the Japanese forces gathering in home waters, nor for all the geographic designators being used by the Japanese as apparent objectives. King concluded his message with two critical pieces of information: the first and only direct allusion to the forces constituting the Japanese Main Body -- "Some indications that remainder of 1st Fleet may take up supporting position west of Midway" -- and he identified Admiral Yamamoto's primary objective: to trap and destroy the U.S. Pacific Fleet.53

Precise Japanese timing continued to elude both the analysts and the commanders. In another estimate, also published on 17 May, Admiral King provided his assessment of when the attack(s) would occur. Based purely on inspired guesswork, he stated there were strong indications that between 30 May and 10 June the enemy would attack the Midway-Hawaii line and would raid or even attempt to capture Unalaska.54

This type of estimate was far too general even for planning purposes, and more precision was soon provided. On 18 May, within the framework of a ubiquitous 10 May request for weather information that may account for the seven-day delay in translation, Commander, CarDiv 1, Admiral Nagumo, revealed a fundamental detail of the Strike Force's attack plan. His message stated that " . . . since we plan to make attacks roughly from the northwest [?] from N minus 2 days until N day request you furnish us with weather reports three hours prior to the time of take- off on said days . . . ." 55 Two additional translations of possibly the same message from different originators were also


published the same day by Melbourne and Hawaii. They contained another vital detail: Japanese planes would be launched fifty miles northwest of AF! 56

These messages did not solve the timing problem completely, but, after weeks filled with uncertainty and concern that the right decisions were being made and executed, it is not difficult to appreciate Admiral Nimitz's reaction. On the same day, he immediately sent messages to CTF 16 (Halsey) and to CTF 17 (Fletcher) to expedite their return to Pearl Harbor, and he redirected submarine search activity off Midway to an area fifty miles northwest of the island.57

On 19 May Layton drew together the recent COMINT from both Pacific centers into a masterful summary that identified the main objectives of the impending Japanese campaigns. He named Midway-Oahu and the Aleutians; isolated their rendezvous as Saipan and Ominato, respectively; and identified Midway and Dutch Harbor as specific Japanese objectives. The arrival of his report in Washington inadvertently coincided with the climax of a problem that had simmered for months between OP-20-G and Admiral Richmond K. Turner, chief of the Navy's Office of War Plans. The relationship, already far from harmonious, had deteriorated steadily since early March. At that time, newly formed OP-20-GI (Combat Intelligence) and OP-20-GZ (Translation) began to produce "current" intelligence reports based on the output of the Pacific centers and current translations after 13 March 1942, based on the work of OP-20-GY (Cryptanalysis). The final breakdown stemmed from a series of minor disagreements between the analysts in War Plans and their counterparts in OP-20-G concerning Japanese preparations for the Midway/Aleutians campaigns.

The available record of the dialog between War Plans and OP-20-G reveals a very active and sometimes acrimonious relationship, touching on virtually every Japanese Navy initiative between 14 March and 27 May 1942.58 Disagreements were often so profound that the head of OP-20-G, Commander John R. Redman, frequently had to rewrite the intemperate comments of the analysts who prepared responses to the questions from Admiral Turner and his staff. The record, unfortunately, also reveals that analysts in both War Plans and NEGAT were often unaware of the decisions and actions emanating from both Admiral King and Admiral Nimitz, particularly during the critical period between 8 and 23 May. In addition, the record suggests that the analysts in OP-20-G and War Plans were so engrossed in their own activities that they sometimes overlooked vital information concerning the Imperial Fleet readily obtainable from translations from OP-20-GZ and the daily reports from the Pacific centers.

On 13 May, after the Japanese Fourth Fleet had broken off the Moresby campaign, for example, Admiral King cited several likely Japanese actions, including an attack on Midway and the Aleutians, when he directed Admiral Nimitz to declare a state of Fleet Opposed Invasion. Two days later, after the "Hawaiian charts" message was published, and after Nimitz had implemented the King order to declare an emergency, a memorandum from OP-20-G was passed to War Plans. It did not mention the dialog between King and Nimitz nor the implications of the Japanese Navy's interest in navigation charts for the area around Honolulu and the Aleutians. Responding to


questions from the War Plans staff, it focused on the much narrower views of War Plans regarding several ongoing and unrelated Japanese campaigns including the MO campaign. None of the items cited in the internal exchange contributed to or concerned in any way the current exchange of ideas and initiatives between Admirals King and Nimitz.59

On about 20 May, a face-to-face confrontation occurred between Turner and Redman, in which Redman learned that Turner himself was seriously dissatisfied with certain aspects of the latest COMINT reports from both the Pacific and OP-20-G. Turner specifically accused both NEGAT and the Pacific centers of not resolving the distinction between the AF and K Campaigns, and for failing to perceive that CINC 5th Fleet was in fact merely a Sea Frontier Commander who was not in command of the units that passed through his area of responsibility.60

At the end of the confrontation, Turner literally "directed" Redman to ensure that, unless the files showed evidence to the contrary, the COMINT centers in Washington, Hawaii, and Australia were all to "not comment in such a way as to indicate that CinC 5th Fleet is to command any force now concentrating in Northern Empire Waters, but are to assume that Admiral Turner's views are correct."61 It is significant that throughout the entire record of the confrontation neither party referred to Midway. Instead, through 23 May they usually referred to an undefined and unlocated "AF" operation. Fortunately for the United States, Redman did not have the opportunity to implement Admiral Turner's 20 May directive.

Admiral Turner and his staff were also probably responsible for the fact that, between OP-20-G and the Pacific centers, a question vital to the success of U.S. plans remained unanswered in Washington. What was the identity of "AF," the acknowledged objective of the Japanese Strike Force? The original correlation of AF/Midway had been made by Corregidor on 7 March 1942. It was subsequently reaffirmed by Melbourne shortly after the center was activated on 20 March. Hawaii agreed with Melbourne on the identity of AF because of its position in the "A," or American digraphs in the Japanese designator system. Thus, among the Pacific centers there was no question that Midway was the objective of the Japanese Strike Force.

Admiral Nimitz, his intelligence advisors, and Admiral King agreed with the Pacific center analysts. However, the analysts in OP-20-G and probably the analysts in Turner's War Plans staff never fully subscribed to these shared convictions. NEGAT believed, as noted earlier, that AF was a communications not a geographic designator. Therefore, for a brief period between 15 and 20 or 21 May 1942, OP-20-G, and perhaps others in Washington -- including War Plans -- were apparently overwhelmed by misgivings over the identity of the designator AF. Some subscribed to Samoa, others to the U.S. West Coast, and some to the idea that AF, as a geographic designator, was actually Hawaii itself. 62

Though no direct evidence exists that the following episode actually occurred, HYPO was also aware of the problem. Between 15 and 21 May, so the story goes, someone in Hawaii decided upon a clever method to settle the identity of AF once and for all. Some


attribute the idea to the outspoken Rochefort, whose conviction was long-standing that Midway and AF were the same. The idea was to deceive the Japanese by faking a water shortage on Midway. With the permission of CINCPAC, who had to approve all deception projects, a message reportedly was sent to Midway on 18 or 19 May via the cable from Honolulu directing the station to send a radio message in the clear to the 14th Naval District complaining of a shortage of water.63

This order was apparently carried out promptly and with gratifying results. On 22 May Melbourne published the following translation:

KIMIHI (Naval Intelligence Tokyo) -- The AF (Midway) air unit sent following radio message to Comdt 14th District: "AK" on 20th. 'Refer this unit's report dated 19th, at the present time we have only enough water for two weeks. Please supply us immediately.' Note: Have requested 14th District check this message-if authentic it will confirm identity "AF" as Midway.64

This message, regardless of its genesis, ultimately ended all controversy over the identity of AF and of the Japanese objective.65

Rear Admiral Robert A. Theobald

The period between 20 and 27 May 1942 was filled with heavy Japanese communications activity concerning preparations for the impending operations. On the 20th the center in Hawaii reported the appearance of tactical callsigns and exercise radio traffic in naval radio communications. These were the familiar signs of impending operational movements. Their appearance prompted Admiral Nimitz to accelerate his own preparations. The reported movements of slower Japanese vessels toward Ominato was clearly aimed at support of the Northern Force and prompted Nimitz to activate TF 8 under Admiral Robert A. Theobald. The movement of the Midway Occupation Force Transport Group under Rear Admiral Raizo Tanaka was also reported to Nimitz, prompting him to issue the first of a series of situation estimates (on 20, 22, 23, and 27 May). To the COMINT centers the first one was particularly noteworthy because it contained the following statement: "Our sole source of information ... is RI and CI [i.e., communications intelligence]."66

The order activating Admiral Theobald was accompanied by a comprehensive survey of the Japanese Northern Force order of battle and a preliminary timetable. Curiously, Theobald chose to treat both this information and a subsequent refinement containing


more precise timing and a plan of attack as Japanese deception, and he refused to include it in his plans. 67

Though by no means a parallel case to Theobald's miscalculation, Melbourne made what was probably its most significant if not its only serious mistake of the entire Coral Sea/Midway campaign. Based on their analysis of communications activity and not on textual material, on 21 May the analysts at Melbourne incorrectly concluded that "Cinc Combined, while actively cooperating in directing operations in all areas, will not move to any particular area to assume direct command of operations."68 This statement directly concerned Admiral Yamamoto's "Main Body" consisting of battleships, cruisers, destroyers, and a light carrier. This was a powerful covering force assigned to both the Midway and Aleutian campaigns, which, as noted by Admiral King on the 17th, was directly though distantly involved as support to both operations. Melbourne's ill-advised conclusion may in part explain why the subsequent movement of the 1st Fleet from home waters and its presence some 700 miles west of Midway was not detected before the battle was joined. Fortunately, the seeming contradiction between NEGAT and HYPO went unnoticed.69

Admiral Nimitz's undiluted confidence in his communications intelligence organization and in his own strategic and tactical decisions was demonstrated once again during the building crisis in two messages he originated on 22 May; one was sent to Halsey and Fletcher, the other to General MacArthur. In his message to the American carriers, he ordered them to maintain "strict radio silence at all times," particularly among the aircraft "when coming in to land." The admonition was based on frequent reports from HYPO that the Japanese RI effort easily learned of carrier movements in and out of Pearl Harbor simply by monitoring air-ground radio chatter.70 The warning seems to have had little practical effect on the task forces.

He also warned MacArthur that Japanese radio intelligence stations were intercepting air-to-ground radio contacts between Port Moresby and allied planes. He added that if these contacts were enciphered they were quickly and easily broken.71 MacArthur changed his codes immediately.72 This episode also indicated how closely Rochefort and Layton worked together. Both messages from the theater commanders preceded the official notification from Com 14 of their discovery that the Japanese were retransmitting Moresby-related air-ground traffic to nearby surface ships and submarines.73

It is possible the Japanese success in exploiting American radio communications in the southwest Pacific inspired General MacArthur to recommend a brilliant deception scheme using radio communications. On 24 May he proposed that Hawaii, Melbourne, and two or three American naval vessels in the area practice radio deception on the Japanese by creating the impression that a task force had remained in the New Hebrides/Coral Sea area.74 Nimitz, who by then knew that the British were not going to lend Admiral King the carrier he requested to support Admiral Leary,75 enthusiastically approved the idea.76 The seaplane tender Tangier (AV-8) and the heavy cruiser Salt Lake City (CA-25) were quickly tasked to steam around the Coral Sea exchanging carrier and intelligence traffic


with each other and certain shore stations.77 Admiral Nimitz probably never learned the outcome of this charade. However, the results were all that could have been anticipated. Japanese communications analysts detected the spurious radio transmissions and reported to Admiral Yamamoto that while he and the Main Body were en route to Midway an American carrier task force remained in the Coral Sea.78

Melbourne and Washington continued to publish translations that added to the developing mosaic. In the radio communications of an unidentified Base Force on 22 May, Melbourne discovered a message containing the word "Midway." The Japanese message requested the "aerial photographs of Midway (which were handed over to you).79 In a completely different vein, the center in Washington published a message from Admiral Nagumo to the "11 Air Force" [sic] on 24 May concerning the delivery of thirty-three probably ground-based aircraft to an unspecified location by the carriers of CarDivs 1 and 2 and one unidentified vessel. Based on the fact that the carriers called at no port until after the attack on Midway and the northern route followed to their destination virtually precluded a fly-off of any kind, Admiral Nimitz immediately deduced that these aircraft were destined to be the nucleus of a ground- based air unit located somewhere on the new perimeter.80 The existence of these aircraft and their likely purpose was subsequently reflected in the version of CINCPAC Operations Plan 29-42 promulgated on 27 May 1942.81 Their subsequent loss was completely unnoted in accounts of the carrier losses.

Twenty-five May 1942 began with HYPO's discovery of the Japanese Date Cipher. The Americans now possessed the means to determine the missing final ingredient of the Japanese plans: when the attack would take place.82 Application of the new information to translations known to contain dates relevant to the forthcoming operation allowed Rochefort to predict that the Japanese attack on the Aleutians would occur on 3 June and on Midway on 4 June.83 Despite objections from his own staff, Admiral Nimitz decided to base his final timetable on these dates.84

Applying the date cipher to older traffic on the 25th, Melbourne also published a translation dated the 20th that alerted the Pacific Fleet to a major movement of combatants on the 22d. CruDiv 8 and one battleship of BatDiv 3, the Kongo, were scheduled to depart the Inland Sea to rendezvous with the Kirishima, another battleship in the same division.85 CruDiv 8 and the Kirishima were destined to support the Midway Strike Force. The Kongo supported the Covering Group for the Midway Occupation Force. This deployment schedule conflicted slightly with the schedule in Fuchida. Fuchida recorded that the Midway Covering Group and the Strike Force left the Inland Sea after a final rehearsal on the 25th.

Operational activities in the Pacific began to accelerate very early on 26 May. TF 16 (Hornet and Enterprise) under Admiral Halsey returned to Pearl Harbor on the 26th to begin a whirlwind of preparations for battle.86 In reaction to the earlier COMINT report of Japanese intentions to approach from that direction, the submarine Gudgeon was ordered to conduct a surface patrol northwest of Midway.87 In addition, CINCPAC Bulletin No. 72 on the 26th carried the electrifying news to a wide audience including the commander of TF 8, Admiral Theobald, and the other task force commanders, that the Japanese Northern


Force had begun to depart Ominato. In the Bulletin, Layton speculated that its probable destination was the western Aleutians.88 Finally, Com 14 published the news late in the day that all Japanese carriers were probably at sea.89

Messages concerning communications security in the U.S. Pacific Fleet were exchanged with Admiral King on the 26th in the course of which Admiral Nimitz again stated how dependent on communications intelligence his operations were. "Generally speaking our present intelligence is mainly the decoding of 40 percent of the messages copied, and only 60 percent of possible messages are copied." At about this time Admiral King sent an equally candid assessment of COMINT to the Joint Chiefs of Staff. He attributed all of the Navy's progress in the Pacific to the success it was having in obtaining timely information from the Japanese naval codes. Without this information, he said, "disaster is probable."90 (Ironically, within five days of Admiral Nimitz's testimonial, the worst fears of both headquarters became a reality when Admiral Nimitz's final estimate of the makeup of the Japanese Midway Force fell into the hands of a reporter for the Chicago Tribune, who published it in three major daily newspapers.)

Twenty-seven May was a momentous day in Hawaii, both in Headquarters CINCPAC and in the radio intelligence center. On the heels of TF 16, which had arrived the day before, the Yorktown finally limped into Pearl Harbor still showing the damage inflicted during the Coral Sea engagement.91 The good news was offset by bad news from the radio intelligence center: a new cipher had been introduced in the Japanese Navy General Purpose Code that rendered unreadable the texts of almost all messages sent after the 27th.92

Though the impact of the new cipher (Baker 9) was felt at once, intercept did not cease. Communications analysts at HYPO, with the aid of radio direction finding, were able to maintain their usual perspective of Combined Fleet activities including deployment of the Northern and Midway Strike Forces. The summary of communications activity published late on the 27th revealed how effective they could be even without readable messages. The carriers themselves, as well as the 1st Air Fleet, were silent on the 27th but received a message from Tokyo that was sent to a group of addressees correctly identified by Com 14 as the Japanese Strike Force. Seven weather ships were tentatively located northeast of Hawaii with the aid of radio direction finding. Each of the five destroyer squadrons associated with both Strike Forces, including the plane guards for the Midway Strike Force, were identified, located, and correctly associated with the element they supported. All major commands associated with both Strike Forces were either heard or identified as recipients of message traffic.93

Earlier messages in the Baker 8 cipher, however, were available, readable, and highly valuable in discerning Japanese intentions. These included a 25 May message from CINC 5 that contained the tactical callsigns for the Northern Force, its Strike Force, and the Occupation Forces for "AQ" and "AO";94 a vital 22 May message that stated that "heavy bomber force will advance to [Horomushiro] for a period of about 20 days beginning 29 May"; a new translation of the 26 May 2d Fleet message "Occupation Force Operations Order Number 8 " which turned out to concern a "Kazuki Detachment" or "Ikki


Detachment." This unit was intended to "command the 2d Combined Landing force" and occupy Midway's "Eastern Island."95 They also included a Combined Air Force message, probably also from 26 May, indicating the planned use of sixty "enemy engineers," i.e., American engineers then on Wake, in the rebuilding of Midway.96 On the 28th, however, Rochefort announced that no radio communications were heard from the carriers and escorts of the 1st Air Fleet that day and repeated his warning published late on the 26th that the carriers were at sea.97 (As already noted, they departed their anchorages in Japan beginning on the 27th in Japan and the 26th in Hawaii.)

The reports from HYPO and Melbourne produced several reactions in CINCPAC headquarters. Admiral Nimitz alerted the task forces that Strike Force deployments were under way;98 dispatched TF 16, now commanded by Admiral Raymond A. Spruance, for Midway; ordered CTF 8 (Admiral Theobald) to maintain radio silence; warned Admiral Theobald that Intelligence believed that Japanese Aleutian forces included one group destined for Kiska and another possibly for Attu; and alerted Theobald that Japanese heavy bombers would be based at Horomushiro.99 Ironically, Admiral Theobald, who had only just arrived in Kodiak, again did not believe the intelligence, all of which was provided by the RI centers in Melbourne and Hawaii, fearing it was a communications inspired ruse to draw him westward.100 He deployed his main force 400 miles south of his Kodiak base with the objective of preventing the Japanese Navy from getting between him and the eastern Aleutians and Alaska. 101

On 29 May 1942, all the centers continued to analyze Japanese fleet communications patterns and to translate earlier messages in the Baker 8 cipher. These efforts continued to pay steady if uneven dividends. NEGAT reported the departure of Admiral Kondo's Covering Group from the Inland Sea102 and contributed a translation concerning American and British diplomats being exchanged.103 HYPO translated messages concerning Japanese activities in the southwest Pacific that also were not directly related to the impending invasion of Midway. One interesting message in this group concerned captured communications personnel from Corregidor who, during "examination," revealed details of certain navy mainline and submarine communications.104

HYPO also reported on current communications activity related to the forthcoming operations. Extremely active antisubmarine air patrols were detected in the northern area.105 All task force commanders were alerted by American direction finding, which located three Japanese submarines in northern waters106 and one west of Midway. The Akagi was noted breaking radio silence, although none of the carriers in the Midway Strike Force could be located.107 All major forces except the First Air Fleet originated traffic on the 29th, CINC Combined being the most active;108 five Northern Force DDs were noted continuing their movement from Sasebo to Ominato to Abukuma that had begun earlier.109 Also on the 29th, COS 2 was noted sending a message to all forces under his command with information to the Strike Force and the Northern Force signifying that he was supporting both operations.


Japanese Carrier Akagi

Despite the evidence from COMINT that the Japanese Northern Force was now approaching its objective, Admiral Theobald had not originated a plan of operations by the 29th.110 In the absence of a plan from Theobald, but in receipt of Admiral Nimitz' message of the 28th outlining the probable Japanese plan of attack,111 the commander of the Northwestern Sea Frontier asked CINCPAC if he should "evacuate white personnel from Attu and Kiska."112 CINCPAC responded affirmatively,113 and CTF 8 (Theobald) was given the responsibility for conducting the evacuation.114 Understandably alarmed at the COMSEC implications of a successful Japanese attack on a base with communications facilities, the "Vice Chief of Naval Operations" (probably the Director of Naval Communications) sent a message to all bases in Alaska to "burn all U.S. Naval and combined cryptographic aids except those currently effective . . . ."115 Unknown to anyone in Washington, the overall situation concerning American communications security was even worse than suspected.

Far from enjoying total anonymity, American preparations to defend Midway were on the verge of discovery. Japanese traffic analysts reported that 72 of 180 messages from Pearl Harbor were "Urgent." To them this extraordinary increase in high-precedence messages in Hawaiian and Alaskan waters suggested that a U.S. task force was at sea.116 Their suspicions were supported by a Wake report that U.S. patrol planes were operating far from Midway.117 In addition, a COMINT detachment traveling with Admiral Yamamoto reported that a U.S. submarine just ahead of the Transport Group that had left Saipan on the 28th had sent a long urgent message to Midway on the 30th suggesting that the transports had been discovered.118 Incredibly, all of the discoveries concerning U.S. activities made by Japanese COMINT in Tokyo or in the Yamato were withheld from the Midway Strike Force by Admiral Yamamoto. They were not reported to these key subordinates either because he assumed they had heard the Tokyo broadcasts or because he refused to break the radio silence he ordered when they departed home waters.119

On 30 May 1942, the Yorktown (TF 17) slipped out of Pearl Harbor probably detected by the COMINT detachment on the Yamato, but, in an equally bizarre leap of logic, this fact


too went unreported to the rest of the Strike Force because of radio silence restrictions.120 Although the location of the Japanese Strike Force was unknown, except that it was "at sea," the U.S. Pacific Fleet carrier task forces sped on their separate ways to positions near Midway that were dictated by information provided by COMINT. 121

Each center continued to search feverishly for earlier readable messages that would contribute to CINCPAC's decision-making capability, but, as the supply of messages grew smaller, their efforts met with less and less success. The site in Melbourne found an important message dated the 27th that contained the future deployment schedule for a unit of heavy bombers. Ten Type 1 heavy bombers from Misawa Air based at Kisarazu were scheduled to depart for Wake in a three-stage move beginning on 1 June and ending on the 3d. This deployment would place them within range of Midway in plenty of time to participate in any naval action beginning on the 7th.122 Moreover, should the Japanese succeed in seizing Midway, these bombers represented a potential threat to Hawaii. Nimitz reacted to this information by issuing a modification to his OP Plan.123 NEGAT, through analysis of communications activity, confirmed once again that the carrier Ryujo was at sea with the Northern Forces and reported that the commander 6 AAF was probably aboard the Akagi, thus explaining the thirty-three land-based aircraft aboard the carriers in the Strike Force.124

Searching through messages sent prior to introduction of the new cipher, the analysts at HYPO also made the important discovery on 31 May 1942 that fighter pilots from CarDiv 5 carrier Zuikaku were transferred to a probable Northern Force unit leaving Ominato on the 26th.125 This discovery completely ruled out the possibility that the Zuikaku could be called upon to support either the Aleutian or the Midway operation. They also found a message of the 22d probably from Admiral Nagumo, CINC 1st Air Fleet, addressed to all four carriers in CarDivs 1 and 2, CruDiv 8 and a battleship in BatDiv 3. All were called to a conference aboard the Akagi on the 26th, which meant that all were still in port at that time - an important insight into the Strike Force's schedule.126 With the aid of direction finding, HYPO again located the weather ships detected earlier. New data now placed them on the 155E line stretching from Kamchatka to below 25N.127

Admiral Nimitz's operation plan estimated that the attack on the Aleutians would probably come on 3 June. With this in mind, a miniclimax began at Fort Richardson, near Anchorage, part of the Alaska Defense Command, when at 1920Z on 2 June the commander reported Japanese carrier-based planes "less than 400 miles south of Kiska." The Commander, Alaskan Section, to whom this report was addressed, incorrectly assumed the information came from an "RDF fix."128 This report supplemented Bulletin Number 79, already sent to the task forces, which contained the news that a navy patrol plane had made contact with Japanese aircraft 560 miles from Midway at 2140Z on 1 June.129

Another highlight of the events of 2 June was the appearance of "unusual enemy radio activity on a large scale" west and north of the Dutch Harbor radio direction finding site. Dutch Harbor also reported bearings of 320 and 034 degrees. These bearings were probably related to weather-reporting Marus, which the station could not ordinarily


hear.130 The same weather-reporting ships extending from Kamchatka to 24N on the 155E line were again recorded by Com 14 in their summary for 2 June 1942.131

Com 14 and the center in Melbourne both enlarged on the earlier evidence that Japanese bombers from up to possibly three Air Attack Forces were being relocated to positions in the Marshalls and to Wake,132 where they posed a threat to Midway's defenders. As noted earlier, these aircraft potentially represented a large ground-based bomber unit on Midway that would be a serious threat to Hawaii if the Japanese seized Midway. Melbourne's analysis of air activity in the Marshalls provided an important insight into the whereabouts of the Japanese Occupation Forces. They concluded that heavier than normal air reconnaissance, coupled with unusually heavy message traffic to a destroyer unit in the same area, meant that the Occupation Force was approaching the Marshalls.133

Older traffic again paid dividends when three messages sent in the previous cipher, Baker 8, were intercepted between 31 May and 2 June. The brief but readable contents of two of the messages were inconsequential, but the third, intercepted on 2 June, concerned casualties on an unidentified carrier. One of the code groups represented a lost carrier, the name of which ended with kaku. Melbourne analysts reasoned that, since the two carriers of CarDiv 5, Shokaku and Zuikaku were still afloat, the lost vessel must be Ryuukaku. Clearly, American cryptanalysts were having trouble with certain code group meanings within the General-Purpose Code. They had not yet verified the identity of the Japanese carrier (Shoho) sunk on the first day of the Battle of the Coral Sea almost a month before.134

NEGAT did not publish any product related to the forthcoming operations on 2 June 1942. Citing ONI estimates, however, Admiral King's headquarters issued a summary of "estimated changes Orange Fleet" that contained serious errors. Most significant were two errors pertaining to the Japanese Main Body under Admiral Yamamoto and to the Strike Force under Admiral Nagumo. ONI incorrectly estimated that BatDivs 2 and 1, CarDiv 4, and DesRon 3, parts of the Main Body, were still in the "Bonins-home waters area." In fact, on the following day this force was approaching the western edge of the occluded front west and northwest of Midway.135 Perhaps more importantly, ONI chose this moment to report the presence of a fifth carrier, and identified that carrier as the Zuikaku.136 Fortunately, Admiral Nimitz and his intelligence staff had confidence in the information being generated by the centers in the Pacific, and this ONI estimate was not acted upon or repeated to the task forces off Midway.


The Battles Begin

As predicted by HYPO, the Japanese offensive against the Aleutians began on 3 June: Japanese carrier aircraft attacked Dutch Harbor at 1555Z/0655 locally.137 A little over two hours after Admiral Nimitz repeated his second alert, while the Japanese renewed their attack on Dutch Harbor, Midway notified him that the Japanese "Main Body" was sighted at 2100Z by a patrol plane on a bearing of 261 degrees and a distance of 700 miles from Midway.138 Eighteen minutes later, apparently as a result of Hawaii's receipt of the report of another patrol plane, CINCPAC learned that a second group of ships had been sighted. The second, a smaller group of warships and cargo vessels, was located 470 miles from Midway. Nimitz immediately forwarded this information to the task force commanders, to Admiral King, and to General Emmons, COMGENHAWDEPT.139 Two hastily prepared clarifications were sent later that stated his belief that the forces sighted were the "attack and occupation force," the most distant consisting of "11 ships course 090 speed 19." The Strike Force was "expected to be separated."140 All of this information and the roles of CINC 5, CINC 1st Air Fleet, and CINC 2 were included in CINCPAC's Bulletin Number 81 sent in the late afternoon of 3 June.141

Com 14's daily report was released in mid-afternoon on 3 June several hours before the Alaska operations began. It was a timely summary of the knowledge gained from translations and other analysis. Most of it quickly found its way to the task forces. HYPO isolated those units "interested in operations against U.S. possessions." Their report correctly if too briefly identified Admiral Yamamoto, CINC Combined, as "in general charge." The actual role of the First Fleet as "Main Body" of the two operations continued to elude analysis. HYPO reported that Admiral Yamamoto, the commander of this fleet, "appeared only marginally interested in the current operations. All the other major commanders were correctly identified: Admiral Kondo, CINC 2, whose battleships, cruisers, and destroyers supported both the Strike and Occupation Forces, was characterized as "in command of invasion forces in Midway area"; CINC First Air Fleet as "in command of Striking Forces against Central Pacific bases"; and CINC Fifth Fleet as "in command of invasion and Striking Forces in North."142

Com 14's analysis was hampered by the fact that no traffic was originated by any of the Japanese commanders after either 28 or 29 May 1942. Since the entire Combined Fleet observed radio silence and a new cipher was introduced in JN 25 at the same time, analysts were left with virtually nothing to analyze except communications contacts initiated by shore-based radio stations, and old messages to and from ships at sea in the Baker 8 cipher. In the latter category was an errant transmission from the cruiser Nagara revealing her role as flagship of the Strike Force's plane guard destroyers, a fact that was immediately conveyed to the CTFs.143 Shore-station communications, however, remained active. Though messages originated by shore stations could not be read, their contacts revealed that Wake was not a stopping-off place for either the Strike Force or the Invasion Force.


Among the many topics demanding Admiral Nimitz's attention at this time was the need to ensure an adequate flow of information into his headquarters during the forthcoming battles. Recalling the paucity of information available during the Battle of the Coral Sea and mindful that certain matters concerning enemy losses in that battle were still not resolved, Admiral Nimitz sent a quick reminder to Midway and to CTFs 4, 7, 9, 16, and 17: "Successful and timely employment Striking Forces. . . almost wholly dependent on reliable combat intelligence with emphasis on enemy composition, position and condition. Damage to enemy must be carefully evaluated and reasonably certain results be reported. Reports must get through promptly."144 Unfortunately, the record of 4 June suggests that his guidance could not be followed by those he most depended upon, the carriers and the B17s. Obviously full of confidence in his intelligence and his plans for the next day's action, however, Admiral Nimitz also sent this encouraging message to Midway and all task force commanders at the eleventh hour on 3 June: "The situation is developing as expected. Carriers our most important objective should soon be located. Tomorrow may be the day you can give them the works."145

(The next day, 5 June 1942, in apparent response to the Nimitz message cited above, Washington directed the use of new terminology to describe communications intelligence and new cryptographic systems for its transmittal. The abbreviations "DI" for decryption intelligence, "TI" for traffic intelligence, and "RI" for radio intelligence were now mandated. Any message or report containing DI was to be transmitted in the COPEK system. Information from TI alone was to be sent in the CETYH system. Both systems were apparently available to all COMB addressees since there was no immediate change in distribution. 146 It is impossible to determine if this guidance was a help or a hindrance. It is certain, however, that, during the battle, it was ignored by everyone.)

Just after midnight on the morning of 4 June, Nimitz realized that he had not yet advised the task forces how far the "Main Body" was from Midway. Accordingly, he repeated messages sent earlier concerning its course and speed and included the information that this force was now "574 miles" from Midway.147 All remained quiet until shortly after dawn when at 1804Z/0604 local time on Midway on 4 June, a reconnaissance plane from Midway spotted two Japanese carriers and their escorts and transmitted an electrifying report that was immediately repeated by Admiral Nimitz to his task forces, to Admiral King, and to General Emmons: "Many planes heading Midway from 320 distant 150 miles!"148 Less than half an hour later, at 1835Z, Midway was struck by Japanese carrier aircraft.149 History does not provide an explanation of why the Japanese chose to launch aircraft 150 rather than 50 miles from their objective. It is possible that the original translation was somehow flawed. The flaw could have been in any of several places, for example, the preparation, transmittal, or intercept of the text of the message, or in an incorrect code group meaning. All of this mattered very little on 4 June, however, when the Japanese carrier aircraft were spotted on their way to strike Midway.

Of the more than 200 units of the Japanese Combined Fleet deployed in the Alaska and Midway operations, no fewer than 129 were either warships (113) or submarines (16). At Midway, however, primarily because of the requirements of their complex plan and


their losses in the Coral Sea, the Japanese could actually produce but 4 carriers, 17 escorts, 229 aircraft, and 17 seaplanes. The remaining Japanese vessels and aircraft were either committed to the Northern operation or were too far away to support the carriers.150

Compared to the onrushing Japanese Strike and Occupation Forces, the United States Navy was able to muster only seventy-three ships (forty-seven warships and twenty-six submarines). However, the United States was able to concentrate its forces and produce at Midway a slight advantage where it counted the most, at the scene of the battle. The United States had 3 carriers and 22 escorts at sea, 234 aircraft afloat, and 110 at Midway. All of these vessels and aircraft, as well as a few of the submarines, were on the scene at Midway on the morning of 4 June 1942.

In addition, Admiral Nimitz and his task force commanders had other less tangible but invaluable advantages as well: advance knowledge of the identity of Japanese objectives; virtually the entire Japanese Midway and Aleutian Strike Forces order of battle; the organization of the Midway forces, i.e., Striking Force, Occupation Force, Invasion Force, etc.; the preliminary and final timetables of the Midway and Aleutian Striking Forces; the general direction from which each force would approach Midway; and the Midway Striking Force's plan of attack. All of this information was supplied by communications intelligence in time to influence decisively the provisions of Admiral Nimitz's Operations Plan 29-42.

As foretold by Rochefort and Layton, the Battle of Midway occurred three days before Admiral Yamamoto planned to assault the island with his landing forces. The Marines and sailors in their prepared positions on Midway, the Navy and Marine Corps flyers on Midway, the submarines in Task Force 4, the patrol aircraft in Task Force 7, the surface patrols in Task Force 9, the B17s in the 7th Bombing Command, and the carriers of Task Forces 16 and 17 all were ready for the fight. They were ready because Admiral Nimitz was able to position them in the relative certainty that the attacking Japanese warships and carriers would be where COMINT had predicted, at the day and time COMINT had provided.

In the absence of Japanese radio communications from the ships approaching Midway on 4 June, HYPO reported to Admiral Nimitz how they had disposed of their intercept resources to deal with the crisis. Watches were doubled under a "Condition 1" at the intercept station on Oahu,151 and a combination radio direction finding and intercept facility was temporarily established on Midway. Intercepted traffic increased accordingly but not from the onrushing Japanese task forces. HYPO concluded that "excellent radio silence is being maintained despite the reported attacks on them." Thanks to the additional direction finding dispositions on Midway, as well as the reports received from naval aircraft of all types and from the army bombers operating from Hawaii and Midway, Admiral Nimitz was nevertheless in an excellent position not only to keep track of events but actually to control the movements of his own forces in relation to the attacking Japanese. This situation was in sharp contrast to the Battle of Coral Sea only a few weeks before, when CINCPAC was virtually blind to unfolding events.


When radio silence was finally broken by the attacking Japanese at about 1200 Midway local time, their frequencies were immediately intercepted and bearings reported probably by the temporary station at Midway.152 Except for encoded submarine communications, radio traffic consisted largely of plain language air-to-ground exchanges between carrier aircraft and the carriers that ended when the carriers themselves were lost. This information became part of an immense body of data concerning American efforts to learn the locations of the several Japanese task forces involved in the battle.

Admiral Nimitz's appreciation for the magnitude of his victory came gradually from visual observations and not from COMINT. Visual observations, however, were rife with ambiguous directional and ship identification information. More than once CINCPAC pleaded for more precision, particularly in those reports concerning the Japanese carriers.153 In the absence of Japanese carrier communications, it was finally from visual reports that he learned in mid-afternoon of the 4th that Admiral Nagumo had probably lost the four carriers of his Strike Force.154 Precise word of Nagumo's loss did come from COMINT, however, but not until 6 June when HYPO reported that Admiral Nagumo "appeared aboard the heavy cruiser Nagara sometime this morning, apparently having lost his flagship,"155 and Melbourne reported that the Chief of Staff, 1st Air Fleet, was also addressed aboard Nagara.156

As dawn approached on the morning of 5 June, Midway itself was safe. At midnight the night before, Admiral Nimitz had sent his heartfelt congratulations in a message to the task force commanders:

You who participated in the Battle of Midway today have written a glorious page in our history. I am proud to be associated with you. I estimate that another day of all out effort on your part will complete the defeat of the enemy.

That morning there was a growing but not universal consensus that the Japanese were hurriedly leaving the area. At one point during the morning of the 5th, CINCPAC originated a message to both TF 16 and 17, to Midway by cable, and to COMINCH, that the Japanese "will attempt assault and occupation Midway regardless past losses."157 In either case, the task of finding the enemy and inflicting still further punishment was preeminent. No one in CINCPAC headquarters was aware that Admiral Yamamoto had postponed part of the Northern Force's operations and temporarily diverted both the Second Strike Force and the Covering Group to assist Admiral Nagumo in his extremity. They were aware, however, of a report from Melbourne on the 5th that stated that CarDiv 3 "shows slight indication that unit may proceed southward to join forces in Midway area." Fortunately for the American cause, Admiral Yamamoto vacillated for several hours before deciding to cancel his orders and restore the forces diverted from the northern area. 158

In sharp contrast to the voluminous reports from HYPO and his intelligence staff, a more truncated view of events was recorded by the CINCPAC War Plans division. Their daily report to CINCPAC sheds an interesting light on the treatment of information obtained from intelligence sources. While adding nothing positive to the general body of knowledge, their efforts are of interest because they were recorded in the CINCPAC War


Diary; they again demonstrate how, as in Washington, a war plans staff group in a major headquarters experienced difficulty in communicating with its leadership. In the CINCPAC War Diary for 5 June, War Plans summarized the Japanese Order of Battle of the Strike and Occupation Forces only and the results of the battle of 4 June on both sides. Their report did not record losses of a fourth Japanese carrier or the Yorktown, though by 050335Z (041635 Hawaiian War Time) CINCPAC knew of both the Japanese losses and the condition of the Yorktown. The summary ended by documenting the third air attack on Dutch Harbor and the sighting reports of two CVs southwest of that port, information probably received from Admiral Theobald's representative.159

On 6 June, HYPO was aware of and quickly reported the implications of the fact that the flag of the 1st Air Fleet, which was a recognizable communications entity, had moved from the Akagi to the cruiser Nagara. Analysts at HYPO also reported on the 6th that "at 1710 on 5 June CINC Combined began sending tactical traffic thus breaking his silence that began 28 May." Other significant items in COMINT reports for 6 June included the fact that 4AAF was prepared to provide air cover to all retiring elements; a call for CarDiv 5 probably to send the Zuikaku to the area; reflections of a U.S. air attack on Japanese cruisers, possibly the Mogami and the Mikumo; the fact that no carriers had been heard in the Midway area for twenty-four hours; and the startling revelation from radio direction finding that Admiral Yamamoto himself was in the North Pacific possibly in company with two divisions of battleships. This report represented HYPO's discovery of the Japanese Main Body.160

In a War Diary entry for the 6th, War Plans summarized the actions of the 4th and 5th. The Japanese were described as "retiring" as the U.S. search continued. The assessment of Japanese losses did not reflect the by then well-known fact that all four carriers were lost: two CV lost; two CV damaged; two BB damaged; two CA damaged; two AP damaged; and all aircraft either lost or badly damaged. Concerning the Yorktown, which on the 6th was struck by two torpedoes fired by the Japanese submarine I168,161 the War Plans entry noted only that attempts at salvage (from bomb damaged inflicted on the 4th) continued. Finally, the entry also noted that Dutch Harbor experienced its fourth air attack. 162

Admiral Spruance decided that the Battle of Midway ended on 8 June 1942.163 COMINT for 7 and 8 June chronicled the fact that the Japanese were withdrawing in two echelons. One group moved southwest toward Saipan under the protection of the 4AAF and the other, which included Admiral Yamamoto, was withdrawing to the northwest with air support from CarDiv 3.164 All activity was conducted under the direction of Admiral Yamamoto, who was now personally directing the final phases of his Midway operation. Routing of a message for CINC 1st Air Fleet from Ominato via the carrier Ryujo suggested to HYPO that possibly the admiral aboard this carrier from CarDiv 3, Rear Admiral Kakuji Kakuta, was the new senior officer in the 1st Air Fleet. Subsequent communications activity was to negate this suggestion by indicating that Admiral Nagumo was in fact still aboard the Nagara.165 Still sensitive to the fact that a missing Japanese carrier was a potential problem, Layton again sounded the alarm that the carrier Zuikaku could not be


located. His report suggested that it may have been joining the forces withdrawing from Midway. Layton also reported that COMINT indicated no CVs remained among forces that attacked Midway.166

The disparity between current events and War Plans reporting continued for another day. An entry in CINCPAC's War Diary by War Plans on the 7th suggested either that the entry was written before the COMINT report became available or that War Plans analysts were unwilling to accept information from that source. Instead of reporting that all four Japanese carriers had been sunk by American flyers, the entry recorded "incomplete reports" from army bombers and from TF 16 that a possible fourth Japanese CV had been sunk. In the Aleutians, it reported contact with the Japanese was being maintained by PBYs but "no effective attacks by bombers or torpedoes." There was no reflection of the status of the Yorktown, which sank at 0501Z on 7 June 1042.167

By 8 June COMINT from both Melbourne and Hawaii was able to report that the withdrawing Japanese occupation forces under Admiral Kondo appeared to be headed for Saipan. Radio direction finding placed CINC Combined almost due west from Midway, and the remnants of the Strike Force appeared to be heading toward Japan.168 Layton's report for the day once again warned that the Zuikaku appeared to be active and might be en route to join the withdrawing forces.169 HYPO confided to its War Diary that the Japanese in Tokyo had "commenced radio deception and were attempting to give the impression that a large fleet is maneuvering." In its daily report for the 8th, HYPO noted that tactical calls for up to twelve tactical units were traced to Tokyo through the "sloppy communications practices" of the Tokyo operator and DF.170 The 8th was the final day that the CINCPAC War Diary contained any information from War Plans concerning either Midway or the Aleutians. It recorded that the enemy continued to withdraw from Midway and that bad weather in the Aleutians hindered operations. Though the war continued in the Aleutians for several months, the Battle of Midway thus had three endings: on the 6th when Admiral Spruance turned away from his pursuit of the retreating Japanese; on the 7th when Admiral Fletcher's flagship, the Yorktown, finally sank beneath the waves; and for CINCPAC, on the 8th, when his diary no longer reflected an interest in the defeated Japanese forces.


After the battles of Coral Sea, Midway, and the Aleutians, the invaluable contributions made by communications intelligence were recognized by senior naval officials in Washington and Honolulu. In their words, communications intelligence had given the United States a "priceless advantage" over the Japanese.171 In few battles before or since would the navy possess an enemy's order of battle, their plan of attack, and their timetable, all of which had been provided to the naval high command by the communications intelligence units in Hawaii and Australia under the direction of Commander Joseph J. Rochefort and Lieutenant Rudolph Fabian, respectively.


With their performance during this period, both centers reclaimed the synergism that had marked their efforts before Pearl Harbor. There is no doubt that, had he lived to receive the Distinguished Service Medal -- that was eventually posthumously awarded by the secretary of the navy in 1986 for his efforts to support CINCPAC prior to Midway - Commander Rochefort would have said that the medal truly belonged to the entire communications intelligence effort in the Pacific.172 (Fabian too was recommended for a DSM by MacArthur. Like Rochefort's, it too was not approved.)

On the eve of each of the battles fought in May and June 1942, Japanese communications security attempted to prevent U.S. monitors from penetrating the navy's intentions. It was not until the end of May, however, that radio silence effectively eliminated access by HYPO, Melbourne, and Washington to even those few messages related to the impending operations that were exchanged outside the confines of a new cipher and a new call-sign system. Fortunately, the Japanese efforts to protect their secrets came too late to prevent what the world now knows was a major U.S. intelligence achievement.

Armed with the support of excellent communications intelligence and of his superiors in Washington, CINCPAC was able to satisfy all three of Clausewitz's "principles of warfare": decision, concentration, and offensive action. Prior to the invasion of Port Moresby, his fast carrier task forces successfully turned aside the Japanese strike force, virtually eliminated the effectiveness of Carrier Division Five originally scheduled to participate in the Midway operation, and forced postponement of the Japanese strikes on Ocean and Nauru by the judicious placement of CTF 16 when it was certain that the carriers Hornet and Enterprise would be spotted by Japanese patrols.

The same support from communications intelligence also allowed CINCPAC to deploy submarines, ships, B17s, B26s, fighters and observation planes to defend Midway and the Aleutians. By knowing the approximate dates for the planned attacks on the Aleutians and Midway, CINCPAC successfully disengaged his carrier task forces from the South Pacific after Coral Sea without being observed; he successfully redeployed them precisely where they could surprise the unsuspecting Japanese Strike Forces.

Without doubt these were major contributions to a truly decisive American victory, a victory of the magnitude of Salamis in 480 B.C. and Jutland in 1915. As a result of the Battle of Midway, the U.S. Pacific Fleet permanently frustrated all Japanese ambitions to establish a defensive perimeter anchored east of the Marshalls. Most importantly, however, the victory exposed to U.S. Navy planners Japan's incapability to wage effective carrier warfare in the central Pacific. Amidst its unrivaled success, however, this story of the contribution of communications intelligence is not quite complete.

Of the mobile detachments on the Lexington, the Yorktown, and the Enterprise, which accompanied the U.S. task forces (the Hornet had no detachment at Midway), we know in detail from the post-action recollections of Captain Forrest Biard, USN (ret) - who served under Admiral Fletcher, CTF 17, on the Yorktown - the type of contribution probably made to the commanders' tactical decision-making process during Coral Sea. At Midway,


however, we know only that they "provided valuable information after contact was made, through interception of Japanese plain language reports."173 Thus until survivors reveal the detailed contributions made by communications intelligence to the tactical decisions of Admirals Fletcher and Spruance, CTF 17 and 16, respectively, the COMINT chronicle will be missing that part of the story. (Admiral Fullenwider, who supported Admiral Fletcher, is dead. Admiral Spruance was supported by a COMINT detachment for which the linguist was Captain Gilven Slonim, USN (ret). On 16 May 1989, Slonim advised the author that he was preparing a book about his experiences in the "RI" detachments that he plans to have published "in time for the 50th anniversary of the Battle of Midway.")


The Battle of Midway continued long after the combatants retired. Because of the confusion that surrounded the nascent and relatively unfamiliar U.S. Navy policies governing secrecy and need to know in 1942, the Battle of Midway was refought in the newspapers and courthouses of three major U.S. cities -- New York, Chicago, and Washington -- for several weeks after the battle actually ended. At issue was how the Navy knew of Japanese plans, how that knowledge came into the possession of a newspaper reporter, and how the government should handle a serious security violation. In the end no one was ever formally punished for revealing to the public the role communications intelligence played in the Japanese defeat. Whether the Japanese ever discovered that U.S. cryptologists had successfully penetrated their most secret operational code, or even suspected the magnitude of the warning provided by COMINT, remains a matter of conjecture to this day. At the time, however, officials within OP-20-G were certain that subsequent almost draconian corrections in Japanese communications procedures and cryptography were traceable directly to the following events.

On 17 May 1942, the survivors of the Lexington were en route to San Diego and San Francisco aboard the USS Barnett and the USS Elliot. (One account said that Admiral Fitch and Captain Sherman were aboard the transport Chester.) Anticipating their arrival in the United States, CINCPAC sent the following message to Admiral Fletcher, CTF 17, with information copies to COMINCH and the Commandants of the 11th and 12th Naval Districts:

It is imperative that all survivors Coral Sea action being returned Mainland be instructed that they are to refrain from any mention of the action upon their arrival west coast port. Com 11 is requested berth transports where debarkation can be conducted without contact with newsmen. All personnel will probably require reoutfitting. There will be no publicity regarding this matter until Navy Department release. Barnett and Elliot will stop at San Diego to discharge excess personnel en route San Francisco. 174

Despite these precautions by CINCPAC, events aboard the Barnett resulted in even more damaging revelations than those CINCPAC had hoped to prevent. In ancillary actions, CINCPAC learned that medical reports filed in Navy Bureau of Medicine channels revealed the status of American carriers after the battle. In a hasty message on 3 June 1942,


CINCPAC notified COMINCH and requested immediate action to suppress the errant reports.175 At 2050 on 8 June 1942, COMINCH sent the following message to CINCPAC:

Contents of your 311221 May were published almost verbatim in several newspapers yesterday. Article originated with correspondent Stanley Johnson [sic] embarked on [USS] Barnett until June 2d. While your despatch was addressed Task Force Commanders it was sent in channel available to nearly all ships which emphasizes need of care in using channels para. Cominch investigating on Barnett and at San Diego. 176

CINCPAC's message of 311221 May contained his final appreciation of the Japanese order of battle prior to Midway.

True to his word, COMINCH immediately convened several formal inquiry panels, which began gathering depositions from witnesses. The panels inquired into the circumstances aboard the Barnett, which, in addition to most of the crew, carried the executive officer of the Lexington, Commander Morton T. Seligman, and a newspaper correspondent, Mr. Stanley Johnston, back to the United States, and in Chicago in the headquarters Colonel R.R. McCormick's newspaper, the Chicago Tribune, where the story had originated.177 According to Admiral King's biographer, Thomas B. Buell in Master of Seapower, Admiral King "was in a white fury at his headquarters while his staff frantically tried to discover the source of the leak."

By 11 June all of the principals had been interviewed. Those aboard the Barnett were interviewed more than once. Out of this work emerged a very unpleasant picture of official neglect and confusion concerning the safeguarding of communications intelligence both on the Barnett and in the newspapers. Because of the perception that newsmen accompanying U.S. forces were sworn to secrecy, indictments of the principal employees of the Chicago Tribune were sought on 9 June, even before the inquiries were completed. They were returned on 7 July by a Chicago grand jury. At this point serious snags appeared at every turn, and the matter lay in the hands of the grand jury and a special prosecutor for several weeks while the navy added depositions to a record that increasingly showed that Johnston, a British subject, had, with the help or negligence of others, betrayed the trust placed in him.

While many in the navy focused on finding a suitable punishment for Johnston, COMINCH issued another memorandum on 20 June 1942 similar to those he had originated in March and April. It was sent to CINCLANT, CINCPAC, and CDR- SWPACFORCE bearing the subject "Control of Dissemination and Use of Radio Intelligence." Within the navy this would prove to be the only remedial action to come out of the Johnston case.178

On 24 June the New York newspaper PM published a story without attribution announcing that the Justice Department did not plan to prosecute anyone, either in the newspapers or in the U.S. Navy,179 as a result of their role in the revelations. Ironically, three days later the navy discovered that Johnston's own government had earlier declared him "unreliable" as a correspondent.180 It was the same government, however, that subsequently forged the ultimate solution by addressing the correlation between the Johnston revelations and safeguarding communications intelligence.181


On 14 July, the special prosecutor, Mr. William D. Mitchell, transmitted his comprehensive "Report on the Chicago Tribune Case" to Attorney General Francis Biddle and Secretary of the Navy Frank Knox. His conclusion, after he had reviewed the law, the evidence, and the circumstances surrounding the "leak," ended by suggesting that "the game may not be worth the candle" and that the national effort would be better served if the case were dropped.182

In the mind of the special prosecutor, none of his major reasons for dropping the case concerned the safeguarding of communications intelligence. Three salient points concerning the merits of the government's case were cited instead. All were related to the personal behavior of the principals: "1) Johnston said (on 8 June) that he got the information from a paper he found on his desk; 2) Two officers testified seeing Seligman working at a table in his quarters and that before him was a 'writing on Navy paper' giving a list of Jap vessels divided into a 'striking force, support force, etc.'; 3) If, as appears likely, some officer left a copy of that dispatch lying around, it may fairly be said there was as much carelessness on the ship as the Tribune was guilty of, and the Jury may think so." 183

No further action was taken until 15 August 1942, when the British Admiralty delegation in Washington sent a letter to Admiral King expressing concern that the Hearst revelations posed a danger to special intelligence methods, that a trial would further compromise this source, and that "preservation of this invaluable weapon outweighs almost any other consideration." King's reply reassured the British that the U.S. Navy would not do anything to increase the harm already inflicted by the original news story. 184 Five days later, the Chicago Daily Tribune carried the front page story, "U.S. Jury Clears Tribune." This story signaled the end of the grand jury investigation, though no reasons were ever given to the press by Mr. Mitchell, the special prosecutor.

What were the facts in the strange case of Stanley Johnston? As noted above, CINCPAC 311221Z May 42, was the message that passed CINCPAC's final appreciation of the Japanese order of battle for the Battle of Midway to the commanders of Task Forces 16 and 17, Admirals Spruance and Fletcher, respectively. The message was passed in communications channels available to other ships. Contrary to normal practices, which expected communicators to ignore traffic not addressed to their ship or commander, it was probably decoded by communications officers from the Lexington en route home from the loss of their ship at Coral Sea, who were acting as watchstanders aboard the transport USS Barnett (AP-11). Their reason for doing so may have been the presence of the Lexington's executive officer, Commander Morton Seligman. The message was given to Commander Seligman, who, apparently under the impression that he was authorized to do so, showed the message to Johnston, who had been aboard the Lexington during the battle and was being evacuated with the crew. Johnston and Seligman may have shared the same quarters aboard the Barnett. 185

On 7 June 1942, five days after Johnston's arrival in San Diego and one day after CINCPAC's "POA Communique #3" appeared announcing "a momentous U.S. victory," Johnston's story of U.S. foreknowledge of Japanese forces and their plans appeared in the


Chicago Tribune and other newspapers in Washington and New York.186 The headlines that introduced the story on page 4A in the Washington Times Herald for 7 June 1942 revealed without a doubt that the author had been privy to secret material concerning Japanese intentions and strategy: "U.S. KNEW ALL ABOUT JAP FLEET. GUESSED THERE WOULD BE A FEINT AT ONE BASE, REAL ATTACK AT ANOTHER."187

Though he could not know the extent of the duplicity involved, Walter Winchell, in his column in the New York Daily Mirror, characterized the Tribune as having "tossed security out the window." Understandably, Johnston's repeated denials that he had ever seen CINCPAC's message were received with cynical disbelief in Washington. Even his media superiors readily admitted they could not otherwise account for the similarities. 188

On 8 June, following an inconclusive meeting between high naval and newspaper officials, Johnston and his editor in Washington, Arthur Henning, met privately with Vice Admiral Russell Willson, Admiral King's chief of staff. It was during this meeting, as noted by the special prosecutor, that Johnston may have contradicted himself (Admiral Willson was to say that Johnston "confessed") and admitted seeing a list of Japanese vessels. 189 With the concurrence of the secretary of the navy and the president, Admiral King barred Seligman from promotion forever. Seligman retired in 1944. 190

OP-20-G's assessment of the damage done by the Johnston revelations took a long time to develop primarily because the Japanese themselves were slow to change their procedures. Nevertheless, OP-20-G maintained it was no mere coincidence that within a few weeks of the Johnston expose drastic changes were made in virtually all Japanese codes and ciphers including the Japanese Fleet General-Purpose System, which changed on 15 August, only two months into the current cipher. Consistent with these changes, navy monitors also noted the omission of message serial numbers beginning on 15 August and a major change in the Japanese call-sign system on 1 October 1942. 191

All of the Japanese refinements were justifiably described by OP-20-G analysts as serious threats to their capability to produce current intelligence. 192 Thus, it is difficult to say at this point that a single event occurred that prompted Admiral King to decide what course of action he would take. It may have been OP-20-G's concern that a jury trial would have even more painful consequences than those already experienced, or Admiral Willson's reading of the meeting he had had with Johnston, or the trauma of preparing highly classified testimony to be given before a Chicago grand jury. Clearly, Admiral King had decided not to implement the 7 July grand jury indictment when he responded to the British letter in August; and the evidence suggests, albeit weakly, that as early as 20 June he had begun to regret even seeking the indictment.

Throughout the Johnston affair, OP-20-G consistently sought a plausible cover story to minimize the damage already done. They appealed to King for future safeguards to prevent the loss of a vital advantage to the navy. King's reiteration of his restrictions on distribution on 20 June, while perhaps not all that OP-20-G wanted, strongly suggested that these appeals were heard.193


Questions concerning the appropriate applications of communications intelligence to wartime emergencies of all types continued to arise. One problem addressed in December 1942 affected how newspapermen and radio broadcasters treated information they knew originated from enemy communications. A new paragraph was prepared for insertion in the "Code of Wartime Practices for the American Press" by the secretaries of war and navy and sent to the director of censorship for implementation:


To the end that the enemy may not have information concerning any success the U.S. may attain in deciphering his encoded or enciphered communications, no mention should be made of available or captured enemy codes or enemy ciphers, or about the intelligence gained from intercepting and studying enemy radio messages.

A prestigious trade journal gave immediate approval to the addition while at the same time registering the idea that after the war censorship should not continue. After citing a post-Pearl Harbor report that "monstrously exaggerated" U.S. losses as an example of irresponsible behavior, the editorial concluded with some ideas that are still relevant:

As between an ethical professional requirement that a journalist hold nothing back and a patriotic duty not to shoot one's own soldiers in the back, we have found no difficulty in making a choice. Freedom of the press does not carry with it a general license to reveal our secret strengths and weaknesses to the enemy. 194

It was not until 1985 that anyone from the Pacific COMINT centers received any formal recognition for his contribution to either the Coral Sea or Midway victories. In 1985, in response to a massive outpouring of affection from his friends, Joseph Rochefort received the Distinguished Service Medal posthumously from the secretary of the navy. For the rest, their epitaph was most fittingly expressed by a perfect stranger many years later:

History, with its flickering lamp, stumbles along the trail of the past, trying to reconstruct its scenes, to revive its echoes, and kindle with pale gleams the passion of former days. What is the worth of all this? The only guide to man is his conscience. The only shield to his memory is the rectitude and sincerity of his actions. It is very imprudent to walk through life without this shield, because we are so often mocked by the failure of our hopes and the upsetting of our calculations, but with this shield, however the fates may play, we march always in the ranks of honour. 195


Table of Contents
Previous Section* Bibliography


[See the Bibliography for complete citations to the items listed below. For example: "Morison" refers to "Morison, Samuel Eliot. History of U.S. Naval Operations in World War II. (Boston: Little, Brown and Company)"]

1. Hattori, Vol. 11, 131, recorded that Admiral Yamamoto had initially issued an order on 5 November 1941, directing that Midway be captured during the second phase of the war.

2. Morison, Vol. III, 58; Willmott, 116.

3. Willmott, 116.

4. Morison, Vol. III, 59; Fuchida, 66-71, 76; Willmott, 8-9, 16, 33. Willmott records passage of the Naval Expansion Act in June 1940; Morison records the Two-Ocean Navy Act in July 1940. The first bill authorized an expansion of 11 percent. The second bill authorized a 70 percent increase. Rear Admiral Julius Augustus Furer, USN (ret), Administration of the Navy Department in WWII (Washington, 1959), 57.

5. Fuchida, 71.

6. Hattori, Vol. II, 132.

7. Hattori, Vol. II, 133.

8. Fuchida, 48; Hattori, Vol. II, 133

9. Fuchida, 78-84.

10. Fuchida, 91-3; Morison, Vol. IV, 169-75.

11. Fuchida, 72, 95.

12. SRMN012/L and H, 2, 4, and 5 March 1942, RG457, NA.

13. SRMN012/H and L, RG457, NA, 11 March 1942.

14. Dyer, 255.

15. SRH272, RG457, NA.

16. Com 14 14070OZ, CINCPAC Message File, RG38, NA and SRMN012/L, RG457, NA, each 14 May 1942.

17. HC IV W.3.25, 15 May 1942, letter from Redman to Murphy.

18. CINCPAC 130131Z, CINCPAC Message Files, RG38, NA.

19. Fuchida, 120.

20. SRH012, 4 March, and SRNM0123, 0126, 23 March 1942. All RG457, NA.

21. SRNM0473/B, 17 April 1942; SRMN005; and SRNM0697, 24 April 42. All RG457, NA.

22. SRH180 and SRH207, both RG457, NA.

23. Letter of 23 April 1942 to War Plans, HC IV W 111.25.

24. SRNM0643, 0668, and 0673; and SRNS1517 (all of 27 April 1942), and all RG457, NA.

25. SRMN012/L, 27 April 1942, RG457, NA.

26. SRNS1517, 1 May 1942, RG457, NA; Com 14 011108Z, May 1942, CINCPAC Message File, RG38, NA.

27. SRH012, 2 May 1942, RG457, NA.

28. Morison, IV, 88.

29. SRH012 and SRNSI517, 4 May 1942, RG457, NA.

30. SRMN012/H, SRH272/H, 8 May 1942, both RG457, NA.

31. SRNS1517, 9 May 1942, RG457, NA.

32. SRMN012/L, SRH272/H, 9 May 1942; RG457, NA.

33. COMINCH 121945Z May 1942, CINCPAC Message File, RG38, NA.

34. SRNS1517, 13 May 1942, RG457, NA.

35. SRMN005, OP-20G message dated 15 May; SRMN012/H, messages translated and published 14-20 May. All RG457, NA. See also OPNAV 151745Z, CINCPAC Message File, RG38, NA.

36. SRMN012/H, SRNS1517, 13 May 1942, RG457, NA.

37. COMINCH 141627 May, found in Nimitz Command Summary entry for this date. HC IV W 112.2.

38. SRMN012/L, 14 May 1942, RG457, NA.

39. 140639, May Nimitz Command Summary.

40. Morison, Vol. IV, 80; COMINCH 141527Z, May 1942, CINCPAC Message File, RG38, NA.


41. Prange, 46-47.

42. Potter, 79-80; and Layton interview, 221-24 and 231-32.

43. COMGENHAWDEPT to CINCPAC 25193OZ May 1942, CINCPAC Message File, RG38, NA.

44. Potter, 101.

45. Nimitz Command Summary, 16 May 1942, compared to COMINCH 141527Z May 1943 in the same document. For evidence of how closely Hawaii and Melbourne agreed on the Japanese threat to Midway, see also 121945Z May 1942, Nimitz Command summary, HCIVWII.2.2. See also SRMN012/H and SRNS1517, both 13 May, and SRMN012/L 15 May 1942, all RG457, NA.

46. COMINCH to CINCPAC, 15213OZ May 1942, Nimitz Command Summary, Book 1, HCIVWII.2.2.

47. Ibid.

48. Morison, Vol. IV, 80.

49. CINCPAC 160307Z to CTF16, CINCPAC Message file, RG38, NA.

50. Nimitz Command Summary, 16 May 1942, HC IV W 11.2.2.

51. Ibid.

52. CINCPAC 160325Z May 1942, Nimitz Command Summary, Book 1, HCIVWII.2.2 and CINCPAC Message File, RG38, NA.

53. COMINCH to CINCPAC, 172220Z May 1942, Nimitz Command Summary, Book 1, HCIVWII.2.2.

54. COMINCH 172221 Z May 1942, Nimitz Command Summary, Book 1, HCIVWII.2.2.

55. SRNS1517, 18 May 1942, RG457, NA.

56. Com 14 18190OZ May; Com 14 to COMB 020934Z June 1942; all CINCPAC Message File, RG38, NA; SRH272, 18 May 1942, and SRNS1517, 18 May 1942; both RG457, NA.

57. CINCPAC 180403Z, 180357Z and 182145Z May 1942, respectively; Nimitz Command Summary, Book 1, HCIVWII.2.2 and CINCPAC Message File, RG38, NA. CTF 16 was originally ordered to return to Hawaii after Halsey was sighted by Admiral Inouye's patrols. CINCPAC 150023Z May to All TF Cmdrs Pac, and Com 14 152316Z to COMB reflect Japanese reactions; CINCPAC to CTF16 160307Z May 1942. All messages are in the CINCPAC Message File, RG38, NA.

58. Radio Intelligence Passed Outside OP-20-G, HC IV W.3.25; and SRMN005, RG457, NA.

59. 15 May 1942 memo for Commander Murphy from Commander John R. Redman, Chief OP- 20-G, HC IV W.3.25.

60. Such a confrontation can be inferred from the 20 May 1942 letter to OP-20-GI signed by Commander G. W. Daisley in SRMN005, RG457, NA.

61. Ibid.

62. Lord, 21; Morison, Vol. IV, 167-168; both address this issue, and the various alternative identities are seen in the formal and informal correspondence in HCIVWIII.2.25 and SRMN005, RG457, NA.

63. Layton, 421-422.

64. Belconnen to COMB 212245Z May, CINCPAC Message File, RG38, NA; SRNS1517, 22 May 1942. RG457, NA. The quoted extract can be found in HC IV W VII.19. Another version of this text will also be seen in SRH012, Vol. I and SRMN005, RG457, NA.


65. Com 14 to COMB 220732Z, CINCPAC Message File, RG38, NA; See also Layton, 421-22; and Reminiscences, HCIV W X.1, in which Rochefort noted that HYPO was very impatient with those who would not accept the definition of AF as Midway, particularly when they had the same information.

Admiral Turner was relieved as Chief of War Plans on or about 25 May 1942. He was later given command of an amphibious force that subsequently assaulted Guadalcanal. His relief on the eve of a great naval battle is difficult to explain in a positive context, particularly in light of his tense relationships with the Navy's Communications Directorate and others and his apparent isolation from Admiral King. There is some confusion over when his relief actually occurred. His biographer, Dyer (263) said 25 May, but SRMN005 (RG457, NA), a collection of papers related to Midway, contains a situation report signed by Turner dated 29 May. Larrabee (201) indicated reasons outside the navy for his dismissal. According to Larrabee, he was removed at the insistence of General George C. Marshall, COS U.S. Army. In March 1942, according to Larrabee, General Marshall convinced the president that Turner, as a member of the Joint Planning Staff, was too difficult to work with. Larrabee (190) also asserted that in 1942 King shifted Pacific war planning functions to Nimitz after Turner was relieved.

66. Com 14 to COMB 190346Z; Belconnen to COMB 190840Z; COM 14 to COMB 190948Z; Belconnen to COME 191610Z; all May 1942 and all in CINCPAC Message File, RG38, NA; SRH272, 18 May 42; SRMN012/H, 20 May 42; SRMN012/H&L, 21 May 1942; and SRNS1517, 21 May 1942, all RG457, NA; and CINCPAC OPPlan 29-42, 20 May 1942, "Survey of Opposing Strengths," HCIVWVII. 18.

67. CINCPAC to CTG2.1, 222345Z May 1942; CINCPAC 230235Z, May 1942; both in CINCPAC Message File, RG38, NA; Morison, Vol. IV, 166 and 170; Willmott, 327; Lundstrom, 175. For Nimitz' estimates and the influence of COMINT, see Com 14 231922Z May 1942, CINCPAC Message File, RG38, NA; SRMN012/L 24 May 1942, RG457, NA; Nimitz' Command Summary 23 May 1942, HCIVWII.2.2; SRH012, 23 May 1942, RG457, NA; CINCPAC Bulletin #74, 280067Z May 1942; CINCPAC to CTF8, 280245Z May 1942 and 282153Z May 1942, all in CINCPAC Message File, RG38, NA. For Theobald's treatment of COMINT, see CTF8 "Estimate of the Situation," paragraph 14, found in U.S. Navy War College Study of Midway, HCIV W VII 6.

68. SRNS1517, 21 May 1942, RG457, NA.

69. NEGAT predicted the impending departure of this fleet's two battleship divisions, 1 and 2, from Kure in a message on the 21st, but the significance of this information was not emphasized. OPNAV 211639Z to CINCPAC and COMSWPACFOR, CINCPAC Message File, RG38, NA; Hoyt (286) discusses the role of Yamamoto and the Main Body during this campaign, as do Morison and Fuchida.

70. CINCPAC 220135Z, CINCPAC Message File, RG38, NA.

71. CINCPAC 220219Z, CINCPAC Message File, RG38, NA.

72. COMSOWESPAC 230725Z May 1942, CINCPAC Message File, RG38, NA.

73. Com 14 220338Z May 1942 to COMB, CINCPAC Message File, RG38, NA.

74. COMSOWESPAC 240549Z, CINCPAC Message File, RG38, NA.

75. COMINCH to Spenavo London, 181255Z May 1942, info COMSOWESPACFOR and CINCPAC, CINCPAC Message File, RG38, NA.

76. Potter, 88; Willmott, 342.

77. Instructions for the Tangier can be found in 280333Z, May 1942 CINCPAC to the Tangier and COMSOWESPAC, CINCPAC Message File.

78. Fuchida, 130-33.

79. SRNS1517, 24 May 1942, RG457, NA.

80. SRH012, 24 May 1942, RG457, NA; Com 14 to COMB 252126Z May 42, CINCPAC Message File.

81. CINCPAC to CTFs 4, 9, 17, 16, 022319Z June 1942, CINCPAC Message File, RG38, NA.

82. The date of the discovery can be inferred in Potter (82) when he described a meeting on 25 May between Nimitz and Rochefort to which the latter arrived late and in a disheveled condition ostensibly because he was waiting for the cipher solution. This is probably the same meeting Layton places on the 26th. In Com 14 to COMB, 272118Z and 272158Z May 1942, the solution was shared with other COMB addressees (CINCPAC Message File, RG38, NA). It would have been unusual for one center to withhold important information for two days.

83. Layton, 427-28; Com 14 to COMB 272058Z May 1942, CINCPAC Message File, RG38, NA.

84. Potter, 82, 83, 87.


85. SRNS1517, 25 May 1942, RG457, NA.

86. CINCPAC to COMINCH 270209Z May 1942, CINCPAC Message File, RG38, NA.

87. CTF7 to Gudgeon, 260015Z, May 1942; CINCPAC Message File, RG38, NA.

88. CINCPAC 260345Z, CINCPAC Message File.

89. Com 14 to COMB 262244Z May 42, CINCPAC Message File, RG38, NA.

90. Lundstrom, 171.

91. Morison, Vol. IV, 81.

92. OPNAV to COMB 262240Z May 1942, CINCPAC Message File, RG38, NA.; See also Belconnen to COMB 280428Z, May 1942, in same file.

93. SRMN012H, 27 May 1942, RG457, NA.

94. Com 14 280040Z, May 1942, CINCPAC Message File, RG38, NA.

95. Com 14 to COMB 282020Z May 1942; OPNAV to COMB 281650Z May 42, CINCPAC Message File, RG38, NA.

96. SRNS1517, 28 May 1942 RG457, NA; Com 14 to COMB 282009Z May 1942, CINCPAC Message File, RG38, NA; and SRH012, RG457, NA, same day.

97. Com 14 282132Z, May 1942, CINCPAC Message File, RG38, NA.

98. CINCPAC Bulletin 74, 280057Z May 42, CINCPAC Message File, RG38, NA.

99. See CINCPAC to CTF8 280245Z and 282153Z May 42, CINCPAC Message File, RG38, NA.

100. Morison, Vol. IV, 170; and CTF 8 Estimate of the Situation, para. 14, USNWC.

101. Deployment of forces from Morison, Vol. IV, 170; arrival of Theobald in Alaska from Nimitz Command Summary, HCIVWII.2.2, May 22 when he departed from Hawaii.

102. OPNAV to COMB 292045Z May 1942, CINCPAC Message File, RG38, NA.

103. OPNAV to COMB 290415Z May 1942, CINCPAC Message File, RG38, NA.

104. Com 14 to COMB 290214Z, 290216Z and 291142Z May 1942, CINCPAC Message File, RG38, NA. Corregidor ended operation on 6 May 1942.

105. Com 14 to COMB, 292008Z May 1942, CINCPAC Message File, RG38, NA.

106. Bulletin Number 75, CINCPAC 290231Z May 1942, CINCPAC Message File, RG38, NA.

107. CINCPAC to COMINCH 290419Z May 1942 and CINCPAC to all TFs 291409Z May 1942, both CINCPAC Message File, RG38, NA.

108. Com 14 to COMB 292226Z May 1942, CINCPAC Message File, RG38, NA.

109. Com 14 to COMB 292234Z May 1942, CINCPAC Message File, RG38, NA.

110. CINCPAC to CTF8 292029Z May 1942, CINCPAC Message File, RG38, NA.

111. CINCPAC 282151Z May 1942, CINCPAC Message File, RG38, NA.

112. 282123Z May 1942, CINCPAC Message File, RG38, NA.

113. 291621Z May 1942, CINCPAC Message File, RG38, NA.

114. COMNORWESSEAFRON to CTF8 311429Z May 1942, CINCPAC Message File, RG38, NA.

115. 292002Z May 1942, CINCPAC Message File, RG38, NA.

116. Fuchida, 119.

117. Ibid., 122.

118. Ibid., 119.

119. Ibid., 123-24.

120. Ibid., 119-120; Deployment of TF 17 under Admiral Frank Jack Fletcher, was ordered for 1830 local time 30 May 1942 in CINCPAC 290205Z May 1942, CINCPAC Message File, RG38, NA.

121. CINCPAC OpOrder 29-42, 27 May 1942, gave the Japanese rendezvous point at 27N, 170E. See also CINCPAC to CTF 16, 300227Z May 1942; and CINCPAC Bulletin Number 76 sent to all TF Cmdrs, etc., 300241Z May 1942, all CINCPAC Message File, RG38, NA.


122. Belconnen to COMB 300440Z May 1942, CINCPAC Message File, RG38, NA.

123. Operations Plan 29-42 published on 2 June. CINCPAC to CTFs 4, 9, 17, 16, 022319Z, June 1942, CINCPAC Message File, RG38, NA.

124. OPNAV to COMB 302025Z, May 1942, CINCPAC Message File, RG38, NA.

125. Com 14 to COMB 310545Z, May 1942, CINCPAC Message File, RG38, NA.

126. Com 14 to COMB 310934Z, May 1942, CINCPAC Message File, RG38, NA.

127. Com 14 to COMB 312154Z, May 1942, CINCPAC Message File, RG38, NA.

128. COMALSEC to CINCPAC, CTF8 022130Z, CINCPAC Message File, RG38, NA.

129. CINCPAC to CTFs, etc., 020347Z, CINCPAC Message File, RG38, NA.

130. Dutch Harbor to CTF 8, 021430Z June 1942, CINCPAC Message File, RG38, NA.

131. Com 14 to COMB 020024Z June 1942, CINCPAC Message File, RG38, NA.

132. Com 14 to COMB 020024Z June 1942 and Belconnen 020335Z, 020426Z and 020630Z June 1942, all CINCPAC Message File, RG38, NA.

133. Ibid.

134. Ibid.

135. Morison, Vol. IV, see map after p. 94.

136. OPNAV to CINCPAC, etc., 022231Z June 42, CINCPAC Message File, RG38, NA.

137. CINCPAC to All CTFs, 031637Z; CINCPAC to Midway, information to all CTFs 031855Z, repeated 031927Z; COMNOWESTSEAFRON to CINCPAC, COMINCH 031941Z; NAS Dutch Harbor to CTF8, Com Alaskan Sector, Casco 032215Z and to CTF8, 040030Z; all June 42, all CINCPAC Message File, RG38, NA.

138. Midway to CINCPAC, 032135Z, June 1942, CINCPAC Message File, RG38, NA.

139. CINCPAC to CTFs, info COMINCH and COMGENHAWDEPT 032153Z, June 1942, CINCPAC Message File, RG38, NA.

140. CINCPAC to CTFs, info COMINCH, 032207Z and 040017Z June 1942, CINCPAC Message File, RG38, NA.

141. CINCPAC 0401OIZ June 1942, CINCPAC message rile, RG38, NA. Daylight in Hawaii in June occurs roughly between 1700Z and 0500Z. Allowing for Daylight Saving Time, i.e., War Time, there would have been a twelve- instead of an eleven-hour difference between GMT and the time at Midway and an eleven-hour difference in Hawaii.

142. Com 14 to COMB 030046Z June 1942, CINCPAC Message File, RG38, NA.

143. Ibid. See also CINCPAC Message File, RG38, NA, 030047Z June 1942.

144. CINCPAC to Midway, CTFs 4, 7, 9, 16, 17 030325Z, June 1942, CINCPAC Message File and CTF 7 to TF 7 030619Z June 1942, CINCPAC Message File, RG38, NA.

145. CINCPAC Message File, RG38, NA, 040801Z June 1942 [032301W June 1942].

146. OPNAV/COMINCH to COMB Adees, 042000Z June 1942, CINCPAC Message File, RG38, NA.

147. CINCPAC to all CTFs 041035Z, June 1942, CINCPAC Message File, RG38, NA.

148. CINCPAC 041809Z June 1942/0609 on Midway, 0709 in Hawaii, CINCPAC Message File, RG38, NA, An 1804Z sighting report gave the distance from Midway as 180 miles. CINCPAC Message File RG38, NA, 041857Z June 1942.


150. Fuchida, 86; Willmott, 343; and Morison, Vol. IV, 84.

151. SRMN012/H, 4 June 1942, RG457, NA.

152. Com 14 to COMB 042136Z June 1942; CINCPAC to TFs 11, 16, 17, 042349Z; Com 14 to COMB 042358Z; Com 14 to NAVAIRSTA Midway 050059Z [041459HWT]; and CINCPAC to CTF 16, CTF 17, 050233Z [041733HWT] all June 1942 and all CINCPAC Message File, RG38, NA.

153. See, for example, CINCPAC to Midway 042340Z [1440HWT]; CINCPAC to all CTFs 050045Z [041545HWT], all June 1942 and all CINCPAC Message File, RG38, NA.


154. See CTF 16 to CINCPAC 050204Z June 1942 [1604 MWT, 4 June 19421; CINCPAC to Midway 050335Z June 1942 [1835 HWT, 4 June 19421 and; CINCPAC to all CTFs COMGENHAWDEPT, COMINCH, and COMSOUPAC 050355Z June 1942 [1855HWT, 4 June 19421, all in CINCPAC Message File, RG38, NA.

155. SRMN012/H, 6 June 1942, RG457, NA.

156. SRNS1517, 6 June 1942, RG457, NA.

157. CINCPAC Message File, RG38, NA, 051915Z [061015W] June 1942.

158. Morison, Vol. IV, 178-79.

159. Morison, Vol. IV, 179, describes how Admiral Nimitz was kept abreast of developments by these reports.

160. SRMN012/H 6 June 1942, RG457, NA.

161. Willmott, 508.

162. CINCPAC War Diary, 6 June 1942, ONI Review, May 1947.

163. Buell, 146-47.

164. SRNS1517/RI, 7 June 1942, RG457, NA.

165. SRMN012/H 7 June 1942, RG457, NA.

166. SRMN012/L, 7 June 1942, RG457, NA.

167. CINCPAC War Diary, 7 June 1942, ONI Review, May 1947; and Willmott, 510.

168. SRNS1517/Rl, 8 June 1942; SRMN0112/H, 8 June 1942, both RG457, NA.

169. SRMN012/L, 8 June 1942, RG457, NA.

170. SRMN012/H, 8 June 1942, RG457, NA.

171. Potter.

172. Fabian interview, NSA Oral History, OH 09-8.3

173. SRH289, RG457, NA.

174. CINCPAC 170335Z May 1942, CINCPAC Message File.

175. CINCPAC to COMINCH 032043Z June 1942, CINCPAC Message File.

176. HC IV W 11.2.2 CINCPAC's message of 311221 May contained his final appreciation of the Japanese order of battle prior to the Battle of Midway.

177. Ibid.

178. SRH012, Vol. II and accretion to Vol. II, RG457, NA.

179. HCIV W VII.

180. Ibid.

181. Ibid.

182. HC IV W VII.2. Hereafter, Mitchell report. (U)

183. Ibid.

184. Ibid.

185. Mitchell report.

186. Potter, 82, 103, and SRH012, Vol. II and accretion to Vol. II, show several points of view concerning the situation on the Barnett. This characterization of the role of Commander Seligman is also based on the eyewitness account of Rear Admiral Robert E. Dixon. As CO of the Lexington's Scout-Bomber Squadron Lieutenant Commander Dixon told the FBI on 8 or 9 June 1942 that he had witnessed Johnston taking extensive notes from CINCPAC's 31 May 1942 message. Robert Mason, "Eyewitness," U.S. Naval Institute Proceedings, June 1982,40-45.)

187. HCIV W VII.2.

188. New York Daily Mirror, 7 July 1942, and Mitchell report.

189. HC. IV W VII.2.

190. Mason, Eyewitness.

191. SRH012, Vol. II, Chapter V, 286, and Appendix, 392, RG457, NA.


192. Ibid.

193. SRH012, Vol. II, RG457, NA.

194. Whaley-Eaton American Letter, 12/26/42. These quotations are also in SRH012 Vol. II, Chap. V, 288-91. The Whaley-Eaton American Letter was a business-oriented newsletter published by a company founded in 1918 by Huntington Whaley. Dallas Magazine, March 1986, NEXUS Database.

195. John Colville, Fringes of Power. 10 Downing Street Diaries 1939-1955, New York: W.W. Norton and Co., 1985.


Transcribed and formatted by Patrick Clancey