[159]

VI 
 
A. FINDINGS 
 
1. The basic assumption of the Rainbow Five War Plan was that the United  
States and her Allies would be at war with the Axis Powers, either  
including or excluding Japan. 
 
2. The Wavy Basic War Plan (Rainbow Five) assigned various offensive  
tasks to the Pacific Fleet, including the capture of positions in the  
Marshalls and raids on enemy sea communications and positions, and  
various defensive tasks, including the task of protecting the territory  
of the Associated Powers in the Pacific area and preventing the  
extension of enemy military power into the Eastern Hemisphere by  
destroying hostile expeditions. 
 
3. The Pacific Fleet Operating Plan (Rainbow Five) assigned to the Fleet  
various initial tasks, including the maintenance of fleet security at  
the bases, at anchorages, and at sea, the protection of the  
communications and territory of the Associated Powers by patrolling with  
light forces and patrol planes, the establishment of defensive submarine  
patrols at Wake and Midway, and guarding against surprise attack by  
Japan. 
 
4. The Pacific Fleet Operating Plan (Rainbow Five) and annexes included  
among the initial tasks to be performed by the patrol planes the  
maintenance of the maximum patrol plane search practicable in the  
approaches to the Hawaiian area. 
 
Page 509 
 
5. The Pacific Fleet Operating Plan was to be put into effect on W-day,  
which, it was stated, might or might not coincide with the day that  
hostilities opened with Japan. W-Day was not fixed prior to the attack.  
 
6. The Joint Coastal Frontier Defense Plan, Hawaiian Theater, was based  
on the Joint Army and Navy Basic War Plans. It constituted the basis of  
subsidiary peace and war projects, joint operating plans, and  
mobilization plans. The method of coordination under the plan was to be  
by mutual cooperation until and unless unity of command were invoked. 
 
7. Under the Joint Coastal Frontier Defense Plan the Army's task was to  
hold Oahu against attacks by sea, land and air forces, and against  
hostile sympathizers, and to support the naval forces. The Navy's task  
was to patrol the coastal zone (which included Oahu and such adjacent  
land and sea areas as were required for the defense of Oahu), and to  
patrol and protect shipping therein, and to support the Army forces. 
 
8. One of the specific tasks assigned to the Navy in the Joint Coastal  
Frontier Defense Plan was that the Commandant, FOURTEENTH Naval  
District, should provide for distant reconnaissance. 
 
9. The Joint Coastal Frontier Defense Plan was placed in effect on 11  
April 1941 by the Commanding General, Hawaiian Department, and by the  
Commandant, FOURTEENTH Naval District. 
 
[160] 10. Annex VII, Section VI, to the Joint Coastal Frontier Defense  
Plan was an agreement between the Commandant, FOURTEENTH Naval District,  
and the Commanding General, Hawaiian Department, as to joint defensive  
measures for the security of the Fleet and for the Pearl Harbor Naval  
Base against hostile raids or air attacks delivered prior to a  
declaration of war. 
 
11. Annex VII, Section VI, to the Joint Coastal Frontier Defense Plan  
provided, among other things, for joint air operations and provided that  
when naval forces were insufficient for long distance patrol and search  
operations and Army aircraft were made available, the latter would be  
under the tactical control of the naval commander directing search  
operations.  
 
12. Annex VII, Section VI, to the Joint Coastal Frontier Defense Plan  
also provided that the Army was to expedite the installation of its  
aircraft warning service, and that prior to the completion of that  
service, the Navy, through the use of radar and other appropriate means,  
would endeavor to give such warning of hostile attacks as might be  
practicable.  
 
13. Annex VII, Section VI, of the Joint Coastal Frontier Defense Plan  
provided that when the Commanding General and ComFOURTEEN agreed that  
the threat of a hostile raid or attack was sufficiently imminent to  
warrant such action, each commander would take steps to make available  
to the other the air forces at his disposal, in order that joint  
operations might be conducted in accordance with the plan. 
 
14. The Commanding General and ComFOURTEEN did not effect any agreement  
prior to the attack that the threat of a hostile raid or attack was  
sufficiently imminent to warrant placing Annex VII, Section VI, in  
operation. 
 
15. The Naval Base Defense Force Operation Plan provided, among other  
things, for a Base Defense Air Force in conjunction with  
 
Page 510 
 
the Army. One of the assumptions was that it was possible that a  
declaration of war might be preceded by a surprise air attack on ships  
in Pearl Harbor, that it was probable that there might be a surprise  
submarine attack on ships in the base area, and that a combination of  
both forms of attack was possible.  
 
16. The joint estimate by Admiral Bellinger and General Martin stated,  
among other things, that the most likely and dangerous form of attack on  
Oahu would be an air attack that would most likely be launched from  
carriers which would probably approach inside of three hundred miles.  
The estimate also stated that any single submarine attack might indicate  
the presence of considerable undiscovered surface forces, probably  
composed of fast ships accompanied by a carrier. This Estimate came to  
the attention of Admiral Kimmel and Admiral Bloch.  
 
17. The Naval Base Defense Air Force Plan was prepared by Admiral  
Bellinger and approved by Admiral Bloch. This plan, which was designated  
Annex "Baker" to the Naval Base Defense Force Operation Plan, made  
specific provision for joint air operations by the Army and Navy. The  
plan was effective upon receipt. It was to become operative without  
signal in the event of a surprise attack, or might be made operative by  
dispatch. In the meantime, conditions of readiness for aircraft were to  
be as directed by the Commanding General, Hawaiian Department, for Army  
units, and by [161] ComFOURTEEN, as Naval Base Defense Officer, for Navy  
units.  
 
18. The Pacific Fleet letter on security of the Fleet at base and in  
operating areas, which was reissued by Admiral Kimmel in revised form on  
14 October 1941, provided that the Fleet's security was predicated on  
several assumptions, one of which was that a declaration of war might be  
preceded by a surprise attack on ships in Pearl Harbor, a surprise  
submarine attack on ships in the operating areas, or a combination of  
the two. This letter also stated that a single submarine attack might  
indicate the presence of a considerable surface force probably composed  
of fast ships accompanied by a carrier. 
 
19. The Pacific Fleet security letter prescribed security measures,  
including provisions for defense against air attack. It provided, among  
other things, that ComFOURTEEN, as Naval Base Defense Officer, should  
exercise with the Army joint supervisory control over the defense  
against air attack and that he should take other action, including  
supervisory control over naval short-based aircraft, and arrange through  
the Commander of Patrol Wing Two for coordination of the joint air  
effort by the Army and the Navy. 
 
20. Under the Pacific Fleet security letter, the security measures were  
to include intermittent patrols to consist of a destroyer offshore  
patrol, and an air patrol. The air patrol was to consist of daily search  
of fleet operating areas as directed by Aircraft Scouting Force, one  
covering the entry or sortie of a fleet or task force, and one during  
the entry or departure of a heavy ship at other times.  
 
21. The only local defense plans in effect and operative prior to the  
attack of 7 December 1941 were the Joint Coastal Frontier Defense Plan,  
under which the Navy was obliged to provide distant reconnaissance, and  
the Pacific Fleet security letter, under which the only aircraft patrol  
from Oahu was a daily search of fleet operating areas, a search during  
entry or sortie of a fleet or task force, and during the entry or  
departure of a heavy ship at other times.  
 
Page 511 
 
22. The Pacific Fleet Operating Plan (Rainbow Five), approved by the  
Chief of Naval Operations, in estimating probable enemy (Japanese)  
action, visualized that one of the enemy defensive efforts would be  
"destruction of *threatening* naval forces"; that initial action would  
include "possible raids or stronger attacks on Wake, Midway, and *other  
outlying* United States *positions*"; and that the initial Japanese  
deployment would include raiding and observation forces *widely  
distributed in the Pacific*, and that *submarines* in the *Hawaiian  
area* . . ." [Italics supplied.] The possibility of an attack on Hawaii  
was, therefore, included but in no way emphasized.  
 
23. Admiral Kimmel was of the opinion, throughout his tenure of command  
of the Pacific Fleet, that a surprise air attack on Pearl Harbor was a  
*possibility*. Neither he nor the key members of his staff appear to  
have considered it as a serious *probability*.  
 
24. The method of command established in the local plans was that of  
"mutual cooperation." The relations between the responsible commanders  
were cordial. However, there was not in existence, prior to the attack,  
any permanent operating setup which could insure the constant and timely  
exchange of information, decisions, and intended courses of action so  
essential to the efficient conduct of joint operations, particularly in  
an emergency. A recent proposal looking to the establishment of a Joint  
Command Center had been the subject of adverse recommendations by the  
responsible local commanders, both Army and Navy.  
 
[162] 25. In accordance with "Joint Action," unity of command for the  
defense of Oahu could have been placed in effect by local agreement  
between the Commanding General of the Hawaiian Department and the  
Commandant of the FOURTEENTH Naval District. The latter, however, would  
naturally not make such an agreement without the approval of his  
immediate superior, the Commander-in-Chief, Pacific Fleet. The question  
of unity of command for outlying islands was discussed between Admiral  
Kimmel and General Short in connection with a proposal for reinforcement  
of Wake and Midway by Army planes. General Short's position was that if  
Army forces were involved, the command must be his. Admiral Kimmel  
maintained that the command of naval bases must remain with the Navy.  
The islands were reinforced with Marine planes.  
 
26. Japanese espionage at Pearl Harbor was effective and, particularly  
during the critical period 27 November to 7 December 1941, resulted in  
the frequent transmission to Japan of information of great importance  
concerning the Pacific Fleet, the movements and locations of ships, and  
defense preparations.  
 
27. Certain reports sent by the Japanese Consul General via a commercial  
communications company at Honolulu in the week preceding the attack  
indicated the likelihood of an air attack on Pearl Harbor. 
 
28. It will appear subsequently that various coded messages sent by the  
Japanese Consul General at Honolulu, which did not indicate the  
likelihood of an air attack on Pearl Harbor, were intercepted by Army  
and Navy radio intercept Stations and were decoded in Washington, D. C.  
prior to the attack; that others which were obtained at Honolulu by  
Naval Intelligence prior to the attack were, with the exception of a few  
unimportant messages, in a code which could not be decrypted there  
before December 7th and, that three messages intercepted by  
 
 
 
Page 512 
 
Army radio intercept stations at Hawaii and at San Francisco, which  
indicated the likelihood of an air attack, were forwarded to the War  
Department for decryption but were either not received there prior to  
the attack or were not decrypted prior to the attack. If the United  
States intelligence services had been able to obtain and to decode and  
translate promptly all of the espionage reports sent by the Japanese  
Consul General during the period 27 November to 7 December 1911, the  
information so obtained would have been of inestimable value.  
 
29. Naval Intelligence was effectively organized to acquire information  
from coded diplomatic messages between the Japanese Government and its  
representatives. Through the interception of Japanese diplomatic  
messages and their decryption and translation in Washington, D. C.,  
prior to the attack, knowledge was obtained of the Japanese Government's  
actual views concerning the diplomatic situation, of the Japanese  
Government's intention to wage war, and of the fact that hostilities  
were impending and imminent.  
 
30. The information acquired in Washington through the interception of  
Japanese diplomatic messages was adequately and promptly disseminated at  
Washington by Naval and Military Intelligence to the Chief of Naval  
Operations, to the Army Chief of Staff, to the State Department, and to  
the President. 
 
[163] 31. The Commander-in-Chief, Pacific Fleet, had to rely upon the  
Chief of Naval Operations for information as to the status of the  
diplomatic negotiations with the Japanese, and had requested to be kept  
fully informed on this subject.  
 
32. The Japanese diplomatic messages acquired by Naval Intelligence at  
Washington were not transmitted to the Commander-in-Chief, Pacific  
Fleet, as such. Reasons advanced for this course of action were that the  
Japanese might intercept the naval messages and learn of the Navy's  
success in decrypting Japanese codes; that the volume of intercepted  
messages was so great that the transmission of them, particularly during  
the critical period, would have overtaxed the Navy's communications  
facilities; and, that it was the duty of the Chief of Naval Operations  
to evaluate such information and to advise CincPac of the important  
facts learned.  
 
33. Various of the warning messages sent by the Chief of Naval  
Operations to the Commander-in-Chief, Pacific Fleet, were based on the  
information obtained from intercepted Japanese messages.  
 
34. The warnings sent to the Commander-in-Chief, Pacific Fleet, during  
November (particularly the "war warning" of the 27th) and early  
December, 1941, indicated in unmistakable language that the diplomatic  
negotiations had ceased, that war with Japan was imminent, and that  
Japanese attacks might occur at any moment.  
 
35. The Chief of Naval Operations did not advise the Commander-in-Chief,  
Pacific Fleet, of certain intercepted Japanese messages indicating  
interest in the location of ships in Pearl Harbor. These were more  
specific than other intercepted messages indicating Japanese interest in  
the movements of ships to or from other ports.  
 
36. The Commander-in-Chief, Pacific Fleet, was not fully advised of  
certain other information obtained from intercepted Japanese messages  
after the November 27th "war warning," which made further evidence the  
termination in fact of the diplomatic negotiations and the Japanese  
intention to wage war. 
 
Page 513 
 
37. On the morning of 7 December 1941, there was brought to the  
attention of the Chief of Naval Operations an intercepted message in  
which the Japanese Government instructed its representatives to present  
to the State Department at 1 p. m. the Japanese Government's final reply  
terminating the diplomatic negotiations. Mention was made of the fact  
that 1 p. m. Washington time was about dawn at Honolulu and about the  
middle of the night in the Far East. No one stated that this indicated  
an air attack at Pearl Harbor  
 
38. This so-called "1 p. m. delivery message," which consisted of one  
sentence, had been intercepted at a naval radio intercept station at  
Bainbridge Island in the State of Washington and forwarded to the Navy  
Department by teletype. It was decrypted and available in the Navy  
Department at about 0700 on December 7th. It was sent to the Army for  
translation because there was no Japanese translator on duty in the Navy  
Department at that time. The translation, which could have been done by  
a qualified translator in a few minutes, was not received from the Army  
until after 0900.  
 
[164] 39. Although he was in possession of this highly significant  
information several hours before the attack, and there were available  
means whereby the information could have been transmitted to Admiral  
Kimmel immediately, including a "scrambler" telephone maintained by the  
Army, Admiral Stark initially was not disposed to, and did not, send any  
message to Admiral Kimmel. Instead he relied on the transmission of a  
message by the War Department to General Short, which was to be  
furnished also to Admiral Kimmel.  
 
40. Admiral Stark has previously testified that he did not consider it  
necessary to telephone to Admiral Kimmel on the morning of 7 December  
and that he had not telephoned at any time previous to the attack, but  
that one regret which he had was that he had not telephoned a message  
that morning to Admiral Kimmel or paralleled the Army message on the  
naval radio system. 
 
41. The message sent by General Marshall on 7 December 1941, which was  
received after the attack, advised that the Japanese were presenting an  
ultimatum at 1 p. m., that they were under orders to destroy their code  
machine, that it was not known just what significance the hour set might  
have but that the addressees were to be on the alert accordingly, and  
that the naval authorities were to be informed.  
 
42. The warnings which were sent to the Commander-in-Chief, Pacific  
Fleet, indicated, as to the possible places of Japanese attack, on  
November 24th, that "a surprise aggressive movement in any direction,  
including attack on the Philippines or Guam, is a possibility," and, on  
November 27th, that "an aggressive movement by the Japanese is expected  
within the next few days. The number and equipment of Japanese troops  
and organization of naval task forces indicate an amphibious expedition  
against either the Philippines, Thai or Kra Peninsula, or possibly  
Borneo."  
 
43. Although the warnings which were sent by the Chief of Naval  
Operations to the Commander-in-Chief, Pacific Fleet, drew attention to  
probable Japanese objectives to the southward and southeastward of  
Japan, and did not specifically mention Pearl Harbor, both the Chief of  
Naval Operations and the Commander-in-Chief, Pacific  
 
 
 
Page 514 
 
Fleet, were aware of the possibility of a Japanese attack on Pearl  
Harbor. They did not regard such an attack as probable.  
 
44. The Japanese established several codes in November, 1941, which were  
to be used in radio transmissions to convey to their representatives  
information concerning the status of relations between Japan and the  
United States, and other countries. These were known as the "winds" code  
and the "hidden word" code. The "winds" code was designed to indicate a  
break in diplomatic relations, or possibly war, with England or the  
United States or Russia by the use in weather broadcasts of certain  
Japanese words signifying wind directions.  
 
45. The interception of a "winds" message relating to the United States  
during the first week of December, 1941, would not have conveyed any  
information of significance which the Chief of Naval Operations and the  
Commander-in-Chief, Pacific Fleet, did not already have.  
 
[165] 46. No message in the "winds" code relating to the United States  
was received by any of the watch officers in the Navy Department to whom  
such a message would have come had it been received in the Navy  
Department. No such message was intercepted by the radio intelligence  
units at Pearl Harbor or in the Philippines, although intensive efforts  
were made by those organizations to intercept such a message. The  
evidence indicates further that no such message was intercepted by the  
British or the Dutch, despite their efforts to intercept such a message.  
Neither the Fleet Intelligence Officer of the Asiatic Fleet nor the  
Fleet Intelligence Officer of the Pacific Fleet nor the Intelligence  
Officer of the Far Eastern Section of the Office of Naval Intelligence,  
recalled any such message. The Chief of Naval Operations, the Director  
of Naval Communications, and the Director of Naval Intelligence recalled  
no such message. Testimony to the effect that a "winds" code message was  
received prior to the attack was given by Captain Safford, in charge of  
Op-20-G, a communications security section at the Navy Department, who  
stated that such a message was received on December 3rd or 4th, that it  
related to the United States, and that no copy could be found in the  
Navy or Army files. In his testimony before Admiral Hart, Captain  
Safford named, in addition to himself, three other officers who, he  
stated, recalled having seen and read the "winds" message. Each of these  
officers testified that he had never seen such a message. The only other  
testimony to the effect that a "winds" message was received was by  
Captain Kramer, an intelligence officer assigned to OP-20-G, who said  
that he recalled that there was a message but that he could not recall  
whether or not it related to the United States or England or Russia. It  
may be noted that until he testified in this investigation, Captain  
Kramer erroneously thought that a "hidden word" message intercepted on  
the morning of December 7th had been a "winds" message. 
 
47. On the morning of December 7th, the intercepted "hidden word" code  
message was translated by Kramer. In his haste, due to the necessity of  
delivering other messages, including the "1 p. m. delivery message," he  
overlooked a code word relating to the United States and translated the  
message as meaning only that "relations between Japan and England are  
not in accordance with expectations. He testified that he later  
discovered the error and a few  
 
Page 515 
 
minutes before 1 p. m. on December 7th, he telephoned the correction to  
his superior officer in the Office of Naval Intelligence and to an  
officer of Army Military Intelligence.  
 
48. Except for the omission of the United States, the "hidden word" code  
message was literally translated and did not sufficiently reflect  
previous diplomatic interceptions which indicated that the message was  
to convey the idea of a crisis involving the countries in question.  
 
49. The sources of intelligence as to the Japanese which the Commander- 
in-Chief, Pacific Fleet, had prior to the attack included, in addition  
to the Chief of Naval Operations, the District Intelligence Officer of  
the FOURTEENTH Naval District, and the Fleet Intelligence Officer of the  
Pacific Fleet. 
 
[166] 50. Under the supervision of the District Intelligence Officer of  
the FOURTEENTH Naval District, the telephone lines of the Japanese  
Consul General and the Japanese Vice Consul at Honolulu were tapped for  
some months prior to the attack. These were discontinued on 2 December  
1941 because the District Intelligence Officer feared that the existence  
of such taps might be discovered, resulting in undesirable  
complications. No information of military or naval significance was  
obtained by means of the telephone taps.  
 
51. On 6 December 1941 the local representatives of the Federal Bureau  
of Investigation at Honolulu delivered to the District Intelligence  
Officer a transcript of a trans-Pacific radio telephone conversation  
between a person in Honolulu named "Mori" and a person in Japan. This  
was examined by the District Intelligence Officer. It was decided that  
the conversation should be further studied by a Japanese linguist of the  
District Intelligence Office who was to listen to the recording of the  
conversation. This was not done until after the attack. The transcript  
furnished on December 6th indicated that the person in Japan was  
interested, among other things in the daily flights of airplanes from  
Honolulu and in the number of ships present. During the conversation,  
references were made to flowers, which, it now appears, may have been  
code words signifying the presence or absence of ships and a method of  
conveying information to the approaching Japanese ships, which  
presumably would have been listening in on the conversation. Prior  
investigations indicate that the "Mori conversation" was also brought to  
the attention of General Short on 6 December 1941. 
 
52. Under the supervision of the District Intelligence Officer of the  
FOURTEENTH Naval District. Copies of various cable messages from and to  
the Japanese Consul General at Honolulu, via a commercial communications  
company, were obtained during the first week of December, 1941. This was  
the first time that such messages had been obtained. The messages were  
in code and efforts were made immediately to decrypt and translate them.  
Some messages were decrypted before the attack. These contained no  
information of particular significance.  
 
53. No information secured at Oahu prior to the attack by means of the  
telephone taps or through the interception of messages of the Japanese  
Consul General indicated the likelihood of war or of an attack on Pearl  
Harbor.  
 
54 One of the Japanese Consul General's messages, which was obtained by  
the District Intelligence Officer and turned over on 5  
 
 
 
Page 516 
 
December 1941 to the Radio Intelligence Unit for decryption and  
translation, was a message dated December 3rd. This message was in  
Japanese code known as the "PA-K2." It was decrypted and translated by  
the Radio Intelligence Unit at Pearl Harbor after the attack. The  
message was one in which the Japanese Consul General advised of a change  
in a method which had been established for communication by visual  
signals from Oahu, whereby lights in houses on the beach, the use of a  
sailboat, certain want ads to be broadcast over a local radio station,  
and bonfires, would convey information as to the presence or absence of  
various types of warships of the Pacific Fleet. Although the Radio  
Intelligence Unit at Pearl Harbor was unable to decrypt this message  
prior to the attack, the message was decrypted and translated in rough  
form on 6 December 1941 by a civilian translator in Op-20-G of the Navy  
Department in Washington. That section had received the message from an  
Army radio intercept station at Fort Hunt, Virginia. Captain Kramer  
testified he had no specific recollection of having seen this  
translation prior to the [167] attack, but the evidence indicates that  
the rough translation was shown to him on the afternoon of December 6th  
and that due to the pressure of work on other important Japanese  
diplomatic messages, no action was taken on the translation until 8  
December 1941. 
 
55. On 2 December 1941, the Japanese Consul General at Honolulu received  
a coded message from Tokyo which stated that in view of the existing  
situation, the presence of ships in port was of utmost importance, that  
daily reports were to be submitted, that the reports should advise  
whether or not there were observation balloons at Pearl Harbor, and  
whether or not the warships were provided with anti-torpedo nets. This  
message was intercepted by an Army radio intercept station at Fort  
Shafter, Hawaii, and apparently was forwarded by mail to the War  
Department for decryption and translation. The translation supplied by  
the Army indicates that the message was translated on 30 December 1941.  
 
56. On the afternoon of 6 December 1941, the Japanese Consul General at  
Honolulu sent two messages in the "PA-K2" code which indicated the  
likelihood of an air attack. The first reported that there were no signs  
of barrage balloon equipment at Pearl Harbor, that in all probability  
there was considerable opportunity left to take advantage for a surprise  
attack against Pearl Harbor, Hickam, Ford, and Ewa, and that the  
battleships did not have torpedo nets. The second message reported on  
the ships at anchor on December 6th, and stated that it appeared that no  
air reconnaissance was being conducted by the Fleet air arm. These  
messages were not obtained by Naval Intelligence at Honolulu prior to  
the attack. They were, however, both intercepted by an Army intercept  
station at San Francisco and were forwarded by teletype to the Army. The  
translations of these messages furnished by the Army indicate that they  
were translated on December 8th. They could have been decrypted and  
translated in the Navy Department in about an hour and a half.  
 
57. There were no formal arrangements whereby the Navy communicated to  
the Army estimates of the location and movements of Japanese naval  
forces. Officers of the Far Eastern Section of Military Intelligence at  
Washington had access to charts maintained in the Far Eastern Division  
of the Office of Naval Intelligence showing 
 
Page 517 
 
such information, and had access to radio intelligence information  
available in the Navy Department, and the situation was discussed with  
them. At Pearl Harbor, an intelligence officer of the Hawaiian Air Force  
received some general information concerning Japanese movements from the  
Fleet Intelligence Officer. 
 
58. The War Department had information which led that Department to  
believe that Japanese naval forces were in the Marshalls in November,  
1941. This appears from a War Department dispatch of 26 November 1941 to  
General Short, information to Admiral Kimmel, concerning a special  
photographic reconnaissance to be flown over Truk and Jaluit, in order  
to obtain information, among other things, as to the number and location  
of naval vessels. The reconnaissance was not flown because the special  
Army planes were not made ready.  
 
59. On 27 November 1941, a Pacific Fleet Intelligence Bulletin was  
distributed by the Commander-in-Chief, Pacific Fleet, to his command.  
[168] This bulletin set forth the available information concerning the  
composition of the Japanese Navy. It revised an earlier bulletin on the  
same subject and pointed out that the principal change was a further  
increase in the number of fleet commands. This arose from the regrouping  
of aircraft carriers and seaplane tenders into separate forces. The  
bulletin stated, among other things, that the Japanese Carrier Fleet  
consisted of ten carriers which were organized into five divisions, each  
having two carriers. 
 
60. Current information, derived from traffic analyses, concerning the  
location and movements of Japanese naval forces was obtained by the  
Commander-in-Chief, Pacific Fleet, from the Fleet Intelligence Officer,  
who received it primarily from the Radio Intelligence Unit at Pearl  
Harbor. Such information also was contained in dispatches from the Radio  
Intelligence Unit in the Philippines and from the Far Eastern Section of  
Naval Intelligence in Washington, D. C.  
 
61. Fortnightly Intelligence bulletins were issued by the Office of  
Naval Intelligence and mailed to the Pacific Fleet, among others. These  
included summaries of the information concerning Japanese naval forces  
which had been received from the Radio Intelligence Units at Pearl  
Harbor and at the Philippines. 
 
62. On November 26th, ComFOURTEEN sent a dispatch to OpNav, information  
to CincPac, CincAF, and ComSIXTEEN, which summarized the information as  
to Japanese naval movements obtained by the Radio Intelligence Unit at  
Pearl Harbor during the preceding month. The dispatch indicated that the  
Commander Second Fleet had been organizing a task force comprising units  
of various fleets. This dispatch stated that there was believed to be a  
strong concentration of submarines and air groups in the Marshalls,  
which included at least one carrier division unit (not necessarily a  
carrier), plus probably one-third of the submarine fleet. The estimate  
was that a strong force might be preparing to operate in southeastern  
Asia while component parts might operate from Paleo and the Marshalls.  
 
63. The radio intercepts by the radio intelligence unit located in the  
Philippines were considered by OpNav to be the most reliable because of  
the location of the unit. On 26 November 1941, the radio intelligence  
unit in the Philippines, in a dispatch to CincPac, OpNav and others,  
commented on the above dispatch of ComFOURTEEN and stated that traffic  
analysis for the past few days had indicated that  
 
 
 
Page 518 
 
the Commander-in-Chief Second Fleet, was directing the various fleet  
units in a loose-knit task force that apparently would be divided into  
two sections. The first section was expected to operate in the South  
China area. The second section was expected to operate in the Mandates.  
It was estimated that the second section included "CarDiv 3, RYUJO, and  
one MARU." This dispatch also stated that the ComSIXTEEN unit could not  
confirm the supposition that carriers and submarines in force were in  
the Mandates, and that their best indications were that all known  
carriers were still in the Sasebo-Kure area. It was stated that this  
evaluation was considered to be reliable.  
 
64. From time to time after November 27th, there were sighting reports  
from the Asiatic Fleet and other observers, copies of which were  
received by Admiral Kimmel, which confirmed the movement of important  
Japanese naval forces to the southward of Japan. These, however, did not  
report the movement of carriers.  
 
[169] 65. After November 27th, the Radio Intelligence Unit at Pearl  
Harbor continued the practice of preparing daily summaries of the  
information received through their traffic analysis of Japanese naval  
communications, which were submitted to Layton, the Fleet Intelligence  
Officer, for transmittal to Admiral Kimmel on the following morning.  
Admiral Kimmel received and initialed these summaries daily on and after  
27 November. On December 6th, he initialed the summary dated December  
5th, which was the last one he received prior to the attack.  
 
66. On November 28th, Admiral Kimmel received a communication  
intelligence summary dated November 27th, which stated, among other  
things, that there was no further information on the presence of a  
carrier division in the Mandates and that "carriers were still located  
in home waters." The next day, he received the November 28th summary  
which indicated, among other things, the view that the Japanese radio  
intelligence net was operating at full strength upon U. S. Naval  
communications and "IS GETTING RESULTS." There was no information set  
forth in the summary as to carriers. On the following day, Admiral  
Kimmel received the summary dated November 29th, which, among other  
things, indicated that Carrier Division 3 was under the immediate  
command of the Commander-in-Chief, Second Fleet. On December 1st,  
Admiral Kimmel received the previous day's summary which stated as to  
carriers that the presence of a unit of plane guard destroyers indicated  
the presence of at least one carrier in the Mandates, although this had  
not been confirmed. 
 
67. The December 1st summary, which Admiral Kimmel received, stated that  
all Japanese service radio calls of forces afloat had charged promptly  
at 0000 on 1 December; that previously service calls had been changed  
after a period of six months or more and that calls had been last  
changed on 1 November 1941. This summary stated, and was underscored by  
Admiral Kimmel, that "The fact that service calls lasted only one month  
indicates an additional progressive step in preparing for operations on  
a large scale." It also stated, among other things, that a large number  
of submarines were believed to be east of Yokosuka-Chichijima and  
Saipan, and as to carriers that there was "no change."  
 
68. On 2 December 1941, Admiral Kimmel examined a memorandum which  
Layton had prepared on December 1st at his request. 
 
Page 519 
 
This contained Layton's estimate, on the basis of all available  
information, of the location of Japanese naval forces. This estimate  
placed in the Bako-Takao area Carrier Division 4 and Carrier Division 3,  
which included four carriers, and the "KASUGA MARU" (believed to have  
been a converted carrier). The estimate placed one carrier "KORYU (?)  
plus plane guards" in the Marshalls area. 
 
69. Layton's written estimate made no mention of Japanese carrier  
Divisions 1 and 2, consisting of four carriers. This omission was  
deliberate. The reason was that Layton considered that the information  
as to the location of those carriers was not sufficient to warrant a  
reliable estimate of their whereabouts. 
 
70. On 2 December 1941, Admiral Kimmel and Layton had the following  
conversation:  
 
"[170] Captain LAYTON. AS best I recall it, Admiral Kimmel said, "What!  
You don't know where Carrier Division 1 and Carrier Division 2 are?" and  
I replied, "No. Sir, I do not. I think they are in home waters, but I do  
not know where they are. The rest of these units, I feel pretty  
confident of their location." Then Admiral Kimmel looked at me, as  
sometimes he would, with some what a stern countenance and yet partially  
with a twinkle in his eye and said "Do you mean to say that they could  
be rounding Diamond Head and you wouldtn't know it?" or words to that  
effect. My reply was that, "I hope they would be sighted before now" or  
words to that effect." . . .  
 
"Captain LAYTON. His question was absolutely serious. But when said,  
"Where are Cardivs 1 and 2?" and I said, "I do not know precisely, but  
if I must estimate, I would say that they are probably in the Kure area  
since we haven't heard from them in a long time and they may be  
refitting as they finished operations only a month and a half ago," and  
it was then when he, with a twinkle in his eye, said, "Do you mean to  
say they could be rounding Diamond Head?" or words to that effect. In  
other words, he was impressing me on my complete ignorance as to their  
exact location.... 
 
"Captain LAYTON. This incident has been impressed on my mind. I do not  
say that I quote him exactly, but I do know that he made such a  
statement to me in the way to point out to me that I should know where  
they are but hadn't so indicated their location." 
 
71. The December 2nd radio intelligence summary, which was delivered to  
Admiral Kimmel on December 3rd, stated as to carriers:  
 
"Almost a complete blank of information on the carriers today. Lack of  
identification has somewhat promoted this lack of information. However,  
since over 200 service calls have been partially identified since the  
change on the 1st of December and not one carrier call has been  
recovered, it is evident that carrier traffic is at a low ebb." 
 
72. The radio intelligence summary delivered to Admiral Kimmel on  
December 4th stated, in part, "No information on submarines or  
carriers." The summary delivered on December 5th made no mention of  
carriers. The summary delivered on December 6th stated, in part, "No  
traffic from the Commander Carriers or Submarine Force has been seen  
either." 
 
73. Other than radio intelligence and sighting reports from other  
sources, the only practicable way by which the Commander-in-Chief.  
Pacific Fleet, could have obtained information as to the location or  
movements of Japanese naval forces from 27 November to 7 December 1941  
was by long distance air reconnaissance.  
 
[171] 74. Under the Joint Coastal Frontier Defense Plan, the Navy had  
the obligation, through ComFOURTEEN, to conduct distant reconnaissance,  
and under Annex VII, Section VI, to the Joint Coastal Frontier Defense  
Plan, naval forces were to be supplemented by available Army aircraft if  
the naval aircraft were insufficient for long distance patrol and search  
operations. As previously pointed  
 
out, the latter plan was not in operation because an agreement between t  
the Commanding General and ComFOURTEEN that threat of a hostile attack  
was imminent was a prerequisite and no such agreement had been made  
prior to the attack. The Naval Base Defense Air Force Plan, which  
implemented the agreements for joint Army-Navy air action, similarly was  
not operative prior to the attack.  
 
75. No patrol planes were under the command of Admiral Bloch. The only  
Navy planes suitable for long distance reconnaissance were the Pacific  
Fleet patrol planes. 
 
76. The Pacific Fleet patrol planes were under the control of Admiral  
Kimmel, and he had the responsibility for their utilization. They were  
operated after 22 November 1941 in accordance with schedules approved by  
him at that time, which were not revised prior to the attack. The  
schedules stressed training operations. They did not provide for distant  
reconnaissance from Oahu.  
 
77. Admiral Kimmel testified before the Naval Court of Inquiry that he  
decided on November 27th that there should be no distant reconnaissance.  
 
78. There is no evidence of any specific discussion between Admiral  
Kimmel and members of his staff on or after the receipt of the "war  
warning," as to the advisability or practicability of long range  
reconnaissance from Oahu. The War Plans Officer thought that the subject  
must have been discussed, but could recall no specific discussion. The  
Commander of the Fleet patrol planes, who had not been informed of any  
of the significant warning messages, testified that Admiral Kimmel had  
no such discussion with him. 
 
79. The joint estimate by Admiral Bellinger, Commander, Fleet Patrol  
Planes, and General Martin, Commanding General, Hawaiian Air Force,  
which was used as a basis for the joint Army-Navy agreements, was  
prophetic in its estimate that in the event of attack on Hawaii, the  
most likely and dangerous form of attack would be an air attack to be  
launched at dawn from carriers about 200 miles from Oahu. This estimate  
stated that the action open as a counter-measure included daily patrols  
as far as possible from Oahu, to sectors through 360 degrees, to reduce  
the possibilities of surface or air surprise. It further stated that  
such patrols could be effectively maintained with the personnel and  
materiel available at the time (March, 1941) for a very short period and  
that such patrols were not practicable unless other intelligence  
indicated that surface raid was probable within narrow limits of time.  
According to Admiral Bellinger, it was realized by the responsible  
officers of the Pacific Fleet that another course of action which was  
always open was to fly a patrol of less than 360 degrees, with the  
available aircraft, covering the more dangerous sectors.  
 
[172] 80. A daily search of the Fleet operating areas to the southward  
of Oahu was being carried out prior to the attack, in accordance with  
the provisions of the Pacific Fleet letter on security of the Fleet at  
base and in operating areas.  
 
81. No distant reconnaissance was flown from Oahu during the critical  
period 27 November to 7 December 1941. The last previous distant  
reconnaissance flown from Oahu appears to have been for several days  
during the summer of 1941 on a sector toward Jaluit. This reconnaissance  
had been directed by Admiral Kimmel at Admiral Bloch's request. 
 
82. Late in November, 1941, the Army planned to conduct a reconnaissance  
flight from Oahu to Jaluit and Truk, with the Navy assisting by  
providing intelligence. The reconnaissance was not flown because the  
Army planes were not made ready prior to the attack. 
 
83. The Navy Basic War Plan assigned to the Pacific Fleet the task of  
protecting the territory of the Associated Powers in the Pacific area by  
destroying hostile expeditions and by supporting land and air forces in  
denying the enemy the use of land positions in that hemisphere. Under  
the provisions of Pacific Fleet Operating Plan Rainbow Five, when that  
plan became effective, the Pacific Fleet patrol planes were to maintain  
maximum patrol plane search against enemy forces in the approaches to  
the Hawaiian area, having due regard for time required for overhaul and  
repair of planes and for conservation of personnel.  
 
84. In the war warning of November 27th, which advised that negotiations  
with Japan had ceased and that an aggressive move by Japan was expected  
within a few days, the Chief of Naval Operations directed that Admiral  
Kimmel "execute an appropriate defensive deployment preparatory to  
carrying out the tasks assigned in WPL-46." 
 
85. The dispatch of November 28th repeated an Army dispatch, which,  
among other things, advised General Short that Japanese future action  
was unpredictable but that hostile action was possible at any moment.  
The Navy dispatch directed that Admiral Kimmel as to undertake no  
offensive action until Japan had committed an overt act and that he was  
to "be prepared to carry out tasks assigned in WPL-46 so far as they  
apply to Japan in case hostilities occur."  
 
86. The establishment of long distance air reconnaissance from Oahu  
would have been an "appropriate defensive deployment preparatory to  
carrying out the tasks assigned in WPL 46."  
 
87. The Fleet patrol planes available at Oahu in the week preceding the  
attack sere not sufficient to have conducted 360 degree reconnaissance  
daily for more than a few days. 
 
88. Prior to the attack. Requests had been made by the Pacific Fleet the  
Navy Department to increase the number of patrol planes assigned to the  
Fleet. Some new replacement planes had been sent to the Fleet during  
October and November, 1941. Additional planes, evidenced by the prompt  
arrival of reinforcements after December 7th, could have been made  
available by the Navy Department, but the expense of defenses in other  
areas. The [173] Navy Department presumably knew that the number of  
planes available Oahu were not sufficient to conduct 360 degree  
reconnaissance daily for more than a few days. The evidence in prior  
investigations indicates that after November 27th, responsible officers  
in the Navy Department thought that reconnaissance was being conducted  
from Oahu to the extent practicable with the planes available there.  
 
89. There were sufficient Fleet patrol planes and crews in fact  
available at Oahu during the week preceding the attack to have flown,  
for least several weeks, a daily reconnaissance covering 128 degrees to  
distance of about 700 miles.  
 
90. The sectors north of Oahu were generally recognized as being the  
most likely sectors from which a Japanese attack would come, if the  
Japanese were to attack Pearl Harbor.  
 
 
 
Page 522 
 
91. If a daily distant reconnaissance had been flown from Oahu after 27  
November 1941, with the available patrol planes, the northern sectors  
probably would have been searched. 
 
92. On the morning of 7 December 1941, shortly before the air attack on  
Pearl Harbor, there were reports of suspected and actual hostile  
submarine activity. The second advised of a surface and depth charge  
attack on a submarine. Only the latter report reached responsible  
officers. Due to reports on previous days of sound contacts with  
submarines, confirmation was sought. The action initiated by ComFOURTEEN  
in dispatching the ready duty destroyer, was in accord with the  
provisions of the Fleet's security letter.  
 
93. Confirmation of the report of the sinking of a submarine was not  
received by Admiral Kimmel or by Admiral Bloch prior to the air attack.  
 
94. There is no evidence warranting the conclusion that a Japanese  
submarine entered Pearl Harbor prior to December 7th. The only midget  
submarine known to have been in Pearl Harbor on the morning of December  
7th was sunk after making an ineffectual attack.  
 
95. Evidence of the approach of a large flight of planes from the  
northward, obtained by Army enlisted men operating a radar installation  
for instruction purposes, was not communicated either to the Navy or to  
responsible Army commanders.  
 
96. The Commander-in-Chief, Pacific Fleet, and ComFOURTEEN had no  
previous warning of the air attack, which was initiated by the enemy at  
0755. The attack was skillfully executed, and resulted in serious losses  
of life and damage. 
 
97. The battleships each had two 5" anti-aircraft guns ready and two  
machine guns manned, which was in excess of the requirements of  
Condition III as prescribed in the Fleet Security Letter. As to Fleet  
aircraft based at Oahu, seven were in the air (3 on morning security  
patrol armed with depth charged [sic] and 4 engaged in tactics with  
submarines); ten were on 30 minutes notice: and the balance of forty- 
four on four hours notice.  
 
[174] 98. As a result of adherence to Fleet schedules which had been  
issued in September, 1941, the Pacific Fleet battleships, with one  
exception, were all in port and were either sunk or damaged. Due to the  
fortunate coincidence which resulted in the aircraft carriers being at  
sea, they were uninjured.  
 
99. It has been learned since 7 December 1941, that the Japanese task  
force which attacked Pearl Harbor left Saiki Anchorage, near the Bongo  
Channel, sometime between 20 and 22 November 1941, East Longitude Time  
and proceeded to Tankan Bay, Etorofu Island, in the Kuriles. The force  
then assembled and fueled. It departed on or about 28 November 1941,  
East Longitude Time, and proceeded in an easterly direction to about  
170  West Longitude, then southeast to a point about 200 miles from  
Oahu.  
 
100. The Japanese striking force included three Carrier Divisions, among  
which were Carrier Divisions 1 and 2. Five days before the attack, the  
Fleet Intelligence Officer had advised Admiral Kimmel that he could not  
reliably estimate the location of Carrier Divisions 1 and 2.  
 
101. The Japanese carriers launched their planes from a position 200  
miles due north of Oahu. 
 
Page 523 
 
[175]

CONCLUSIONS 
 
1. The basic war plans and the local defense plans were sound and were  
designed to meet, with the available means, various types of attack,  
including an attack such as the one which was delivered. The basic war  
plans and the local air defense plans were not operative in time to meet  
that attack. The Rainbow Five war plans presupposed the existence of a  
state of war. The local air defense plans presupposed agreement between  
the local commanders that an attack was imminent. Neither of these was  
the case prior to the attack.  
 
2. The system of command in effect in the Hawaiian area was that of  
mutual cooperation and not unity of command. Cooperation between the  
local Army and Navy commanders required agreement as to the imminence of  
attack, which presupposed the possession and exchange of information  
concerning Japanese intentions and movements of Japanese naval forces.  
 
3. A full exchange of information is necessary to the effective exercise  
of Joint Command. While there was a considerable exchange of information  
between various Army and Navy intelligence agencies there was no  
organized system to ensure such exchange. 
 
4. Current and detailed information which was obtained by the Japanese  
as to the location and movements of American naval forces and as to the  
preparations being made for defense against an attack on Pearl Harbor  
contributed to the success of their attack.  
 
5. Information was promptly and efficiently obtained by the United  
States Navy and Army intelligence organizations in Washington,  
concerning the Japanese Government's actual views as to the diplomatic  
negotiations and its intentions to wage war, by means of interception,  
decryption, and translation of Japanese diplomatic messages. 
 
6. The information which was obtained in Washington by the War and Navy  
Departments from Japanese diplomatic messages was fully exchanged. The  
information which was obtained by the Navy Department as to Japanese  
naval movements was available to intelligence officers of the War  
Department in Washington. The War Department had information which led  
that Department to believe that Japanese naval forces were in the  
Marshalls in November, 1941. This appears from a War Department dispatch  
of 26 November 1941 to General Short, information to Admiral Kimmel,  
concerning a special photographic reconnaissance to be flown over Truk  
and Jaluit, in order to obtain information, among other things, as to  
the number and location of naval vessels. The reconnaissance was not  
down because the special Army planes were not made ready. 
 
7. Although the Japanese Government established in their diplomatic  
messages a code, known as the "winds" code, to be used in radio  
broadcasts in order to convey information to its representatives as to  
the status of relations between Japan and other countries, no message  
was intercepted prior to the attack which used the code words relating  
to the United States. 
 
[176] 8. The information obtained by the Navy Department from  
intercepted Japanese diplomatic messages was adequately disseminated  
within the Navy Department. 
 
9. Although Admiral Kimmel some months before had made requests that  
that he be kept fully informed on subjects of interest to the Fleet and  
as to all important developments, the Chief of Naval Op- 
 
 
 
Page 524 
 
erations did not communicate to him important information which would  
have aided him materially in fully evaluating the seriousness of the  
situation. In particular, the failure to transmit the State Department  
message of November 26th and to send, by telephone or other expeditious  
means, information of the "1. p. m." message and its possible import,  
were unfortunate. 
 
10. Admiral Kimmel, nevertheless, did have sufficient information in his  
possession to indicate that the situation was unusually serious, and  
that important developments with respect to the outbreak of war were  
imminent. This included the "war warning" message and similar important  
messages which were sent by the Chief of Naval Operations.  
 
11. The available information in the possession of the Commander-in- 
Chief, Pacific Fleet, as to the existing situation, particularly the  
"war warning" message, was not disseminated to all of his important  
subordinate commanders whose cognizance thereof was desirable. Thus  
Admiral Bellinger, who commanded the patrol planes, and Admiral Newton,  
who was at sea with a carrier and other units, were not informed of this  
and other important messages.  
 
12. Despite the fact that prior to the attack the telephone lines of the  
Japanese Consul General at Honolulu were tapped and that various of his  
cable messages were secured at Honolulu, no information was obtained  
prior to December 7th which indicated the likelihood of a Japanese  
attack. The legal restrictions which denied access to such cable  
messages were a definite handicap to the intelligence agencies in the  
Hawaiian area.  
 
13. Although various messages of the Japanese Consul General at  
Honolulu, which indicated Japanese interest in specific locations of  
ships in Pearl Harbor, were intercepted by radio intercept stations of  
the Army and Navy and decrypted prior to the attack, this information  
was not transmitted by the Navy Department to Admiral Kimmel. Certain  
other messages which were intercepted by the Army prior to 7 December  
1941, indicated the likelihood of attack on Pearl Harbor but were not  
decrypted or brought to the attention of the Navy prior to the attack,  
apparently because the Army did not have sufficient personnel for such  
work.  
 
14. The only practicable sources from which Admiral Kimmel could have  
secured information, after the receipt of the "war warning," as to the  
approach of the attacking force, were the aircraft warning service,  
traffic analyses of Japanese naval communications, and distant air  
reconnaissance from Oahu.  
 
[177] 15. The aircraft warning system was being operated by the Army  
during certain periods of the day primarily for training purposes, and,  
although not fully developed, could have served to give some warning of  
the approach of Japanese aircraft.  
 
16. The principal basis for estimates of the location of Japanese naval  
forces was the intelligence obtained by the Navy from traffic analysis  
of Japanese naval communications.  
 
17. A carrier attack could not, with certainty, have been prevented, for  
the following reasons:  
 
(a) Certain prevention of such an attack requires interception and  
destruction of the carriers before attack planes can be launched. 
 
Page 525 
 
(b) The forces necessary to insure such interception and destruction,  
anywhere in the vast area which would have had to be covered, were not  
available, and could not have been expected to be available. 
 
(c) If the Japanese task force had been detected at nightfall, the  
probability of its successful interception and destruction prior to the  
following dawn would have been small.  
 
18. Prior warning of an impending air attack, even as little as one half  
hour, would have served considerably to reduce the effectiveness of the  
attack, for the following reasons: 
 
(a) Ships' anti-aircraft batteries would have been fully manned and  
ready. It is to be noted that the anti-aircraft fire was more effective  
against the subsequent attacks than the initial air attack. 
 
(b) Enemy character of the approaching planes would have been  
immediately appreciated and they would have been engaged at once. 
 
(c) The maximum condition of damage control readiness would have been  
set, thus facilitating the isolation of damage received. 
 
(d) Many planes could have been in the air, in readiness. 
 
(e) Ground dispersal of planes could have been improved. 
 
19. The only adequate means of assuring detection of an approaching  
carrier attack was by 360 degree distant air search from Oahu.  
Sufficient planes were not available to carry out an all-around distant  
air reconnaissance daily for more than a few days. 
 
[178] 20. A thorough appreciation of the danger, the capabilities of the  
available planes, and the importance of the defense of Pearl Harbor  
might have justified the allotment by the Chief of Naval Operations of  
additional patrol planes to the Pacific Fleet. Although the additional  
planes, if assigned, would not have been sufficient for a 360 degree  
daily search, they would have increased the area which could have been  
effectively covered and might have acted as an inducement to such  
employment. Admittedly, in making over-all plane assignments, it was  
necessary for the Chief of Naval Operations to weigh the prospective  
needs of the Pacific and the Atlantic, where hostilities with Axis  
submarines were already in progress. 
 
21. Partial air reconnaissance, covering a sector of some 120 degrees,  
could have been maintained daily from Oahu for a considerable period of  
time with the Fleet patrol planes controlled by Admiral Kimmel and could  
have been designed to cover the most probable approach bearings from  
which an attack might have been expected. Such reconnaissance would have  
had a reasonable chance of success. 
 
22. Neither the Chief of Naval Operations, the Commander-in-Chief,  
Pacific Fleet, nor the key members of the latter's staff, seem to have  
given serious consideration after 27 November 1941 to the possibility or  
probability of an air attack on Pearl Harbor or of its possible effect.  
 
23. The information as to Japanese naval forces which was available to  
the Commander-in-Chief, Pacific Fleet, emphasizing the movement of  
forces to the southward, tended to concentrate his attention on the  
probability of Japanese attacks on the Philippines and Malaysia. The  
information which was received by Admiral Kimmel during the first week  
of December 1941 indicated, however, that on December 1st there was an  
unusual change in Japanese radio call signs; that, on the basis of all  
information up to December 2nd, no 
 
 
 
Page 256 
 
reliable estimate could be made of the whereabouts of four of Japan's  
ten carriers, and that there was no information as to any of the  
carriers thereafter. The absence of positive information as to the  
location of the Japanese carriers, a study of the movement which was  
possible to them, under radio silence, through the unguarded areas of  
the Pacific, and a due appreciation of the possible effects of an air  
attack should have induced Admiral Kimmel to take all practicable  
precautions to reduce the effectiveness of such an attack. The measures  
which reasonably were open to him were:  
 
(a) Establishment of long distance air reconnaissance, covering the most  
probable approach sectors to the extent possible, on a reasonably  
permanent basis, with available planes and crews.  
 
(b) Establishment of a higher condition of anti-aircraft readiness, at  
least during the dangerous dawn hours.  
 
(c) Establishment of a higher degree of damage control readiness by  
ships in port, particularly during the dangerous dawn hours.  
 
(d) Installation of anti-torpedo nets to protect the larger vessels in  
port.  
 
[179] (e) Maintenance of a striking force at sea in readiness to  
intercept possible attack forces. 
 
(f) Maintenance of the maximum force of the Fleet at sea, with entry  
into port at irregular intervals.  
 
(g Checking with Army as to readiness of anti-aircraft defense and  
aircraft warning installations.  
 
24. Admiral Kimmel's estimate as to the probability of submarine attack  
in the Hawaiian area was justified by subsequent events.  
 
25. Throughout his incumbency as Commander-in-Chief, Pacific Fleet,  
Admiral Kimmel was energetic, indefatigable, resourceful, and positive  
in his efforts to prepare the Fleet for war. In considering the action  
which he could have taken, it should be noted that:  
 
(a) Establishment of the maximum plane reconnaissance would have meant  
the stoppage of aircraft training which was of great importance to the  
naval expansion program, and might have resulted in wear and tear on  
planes and crews which would have reduced their later effectiveness.  
 
(b) Higher conditions of readiness would have interfered with the rest  
and relaxation desirable in port for the maintenance of personnel  
efficiency.  
 
(c) Failure to install anti-torpedo nets was influenced (i) by  
information from CNO which made it appear that effective drops of  
aircraft torpedoes with the depths of water and length of run available  
in Pearl Harbor were not probable; (ii) the interference such nets would  
have caused in harbor operations due to crowded conditions.  
 
(d) The presence of two carrier task forces at sea at the time on  
necessary ferry trips did, in a way, provide striking forces and some  
reconnaissance.  
 
(e) In view of the submarine menace and the concentration of  
antiaircraft batteries, it was questionable whether ships were safer in  
port or at sea. 
 
26. The attempt to obtain confirmation of the reported submarine attack  
off Pearl Harbor was proper, although it should have been effected in  
plain language. Adequate naval action was taken in sending out the ready  
destroyer. This information was of no immediate 
 
Page 527 
 
interest to the Army unless it is [sic] fact indicated imminency of an  
air attack, an assumption which was not necessarily logical. In any  
event, confirmation was not received until the air attack had commenced.  
 
[180]   27. More effective action would have been taken both before and  
after the attack on Pearl Harbor had there been in existence in the  
Hawaiian area a suitable operating agency for the adequate exercise of  
joint command functions. This omission was the fault of no one person,  
but of the existing system.  
 
28. War experience has shown that:  
 
(a) The responsibility for final major decisions must devolve on one  
person; that is, there must be "unity of command."  
 
(b) In planning and executing joint operations, responsible commanders  
of the different services, who are to act jointly, and the principal  
members of their staffs, must be in close physical touch, and not  
entirely dependent on telephonic, radio, or similar communications. In  
no other way can a full exchange of information and ideas be assured nor  
the possibility of misunderstanding be prevented.  
 
(c) Command organizations which are to function effectively in an  
emergency must be in active operation prior to such emergency.  
 
29. Based on the foregoing, military command of outlying stations, such  
as Hawaii, should, even in peacetime, be established under the principle  
of "Unity of Command." The commander exercising such joint command  
should be assisted by a joint staff, capable of advising him in the  
functions of both services concerned 
 
EOF


Page maintained by Larry W. Jewell, lwjewell@omni.cc.purdue.edu. Created: 12/13/96 Updated: 12/13/96