Additional materials are available for the
Gilberts and Marshalls campaigns.
Central Pacific Operations From 1 June 1943 to 1 March 1944,
Including the Gilbert-Marshall Islands Campaign
The summer of 1943 marked the end of the period in which the United States had been strategically if not tactically on the defensive in the Pacific war. The United States position in the Aleutians was secure, vital supply lines to the South and Southwest Pacific were protected by an adequate system of air and naval bases, and in the Solomon Islands and New Guinea Japanese forces were being slowly forced back in campaigns which cost them heavily in naval and air strength. Japan had lost important advanced bases and had suffered steady attrition of her naval and air forces which prevented her from building up offensive power for further assault. United States forces on the other hand were rapidly increasing to the point which would permit a major offensive. However the Allies lacked advanced positions from which Japan's essential supply lines could be attacked or the homeland threatened. At this stage of the Pacific War, while neither opponent possessed important geographical advantages for attack, the advantage in men and materials was shifting definitely to the United States, and United States initiative shaped the remainder of the war.
United States plans for Central Pacific Operations called for capture of a succession of Japanese positions from which attacks could be launched against Japanese strong points such as Truk and the Marianas and also against essential lines of communication. The several directives issued for these operations defined the purposes as to gain control of the Gilbert Islands and the Marshall Islands, to secure a base area for attack on the Carolines, to improve the security of lines of communications, and to support other operations in the Pacific and Indian Oceans by extending the pressure on the Japanese.
United States and Japanese Plans
The Japanese anticipated an eventual attack on the Gilbert-Marshalls Area and in May 1943, to defend this outer line, had prepared the "Z" plan for employing the Fleet, based at Truk, to assist land-based aircraft and garrison troops in the islands.
During the following summer the Japanese position in the Solomons deteriorated to such an extent that the "Z" plan was modified by eliminating the Bismarcks and Gilbert-Marshalls from the vital areas which would be defended by the Fleet. However, garrisons in the Gilbert-Marshalls were to be reinforced and supplemental plans were made to shift land-based aircraft from adjacent areas to meet an attack as it developed. It was also necessary for Japan to consider the possibility of accelerated Allied attacks in the Solomons or New Guinea Areas where Japanese forces were losing ground slowly. The United States not only held the initiative but the choice of several objectives widely separated in a theater whose geography allowed full employment of superior naval and air power.
The first preparatory operation for capture of the Gilbert Islands was the unopposed occupation of islands in the Ellice group in August 1943 and the reoccupation of Baker Island in September. Construction of airfields commenced immediately and by October aircraft of both the United States Army and Navy, operating from these fields, were harassing Japanese forces on Nauru and the Gilbert Islands and were
obtaining valuable photographic intelligence of the latter group. Carrier Task Force raids on Tarawa and Makin during September and on Wake in October reduced the force of Japanese air attacks on United States positions in the Ellice Islands and destroyed a substantial portion of Japanese reconnaissance aircraft strength in the area. During September 1943, United States ground and naval forces were assembled in the New Hebrides and the Hawaiian Islands where training for amphibious operations was begun in October. By the end of that month United States forces for invasion of the Gilberts were almost completely trained and ready to move.
The Solomons and New Guinea campaigns had increased in tempo during this period of preparation forcing the Japanese to divert more aircraft, personnel and light naval ships to meet the Allied thrusts toward Rabaul, the enemy's key base in the Southwest Pacific. The successful United States landing on Bougainville Island 1 November 1943, convinced the Japanese High Command that the threat in this sector was greater than that of attack in the Central Pacific. A number of the naval vessels which had been held at Truk in conformity with the general plan for defense of the Pacific perimeter were sent via Rabaul to assist in checking the United States advance toward Rabaul. This force of cruisers and destroyers was attacked by carrier aircraft within a few hours of its arrival at Rabaul and retired immediately to Truk leaving one cruiser and one destroyer seriously damaged. Upon arrival at Truk, four cruisers which had been damaged to a lesser extent were sent to Japan for repairs. The Japanese thus lost, at least temporarily, a substantial portion of their cruiser strength in the Pacific.
Initial landings on Tarawa and Makin Islands of the Gilbert group were scheduled for 20 November 1943. All United States Forces engaged in these operations were enroute to their objectives by 12 November and on 13 November aircraft based on the Ellice and Baker Islands commenced heavy day and night attacks on the Gilberts. Japanese reaction to the approach and subsequent operations of the attack groups and carrier task forces was limited to air and submarine action. Neither interfered seriously with the landings. Japanese air reinforcements which were flown in from Rabaul and the Empire were not sufficient to maintain aircraft strength in the Marshalls in the face of frequent strikes by United States carrier aircraft and heavy losses suffered by the Japanese in futile attacks on United States surface forces. A small Japanese naval force sortied from Truk on 24 November and remained in the Western Marshalls until 4 December but made no move to interfere with the operations in progress. A few troops were hurriedly despatched from Truk to reinforce certain island garrisons of the Marshalls group.
Occupation of the Gilberts
Despite the failure of the Japanese to reinforce the Gilberts as planned the garrison troops of Tarawa and Makin put up a bitter defense. At Tarawa preliminary bombardment by surface vessels and strikes by carrier aircraft were effective in destroying above-ground installations on the island. However, the time interval between the lifting of the final bombardment and the arrival of the first assault wave was too great. This was caused by unexpected current, slowness of the assault boats, and difficulty with depth of water at the outer reef. The lack of covering fire at the critical time of landing resulted in heavy losses during the first phase of assault. United States Marines sustained 20 percent casualties among the 15,000 combat troops employed during the assault and the ensuing 2 1/2 days of hand-to-hand fighting required to eliminate the garrison force. Only 146 prisoners were taken of an estimated 4,800 Japanese garrison and labor troops.
Makin Island, attacked at the same time, was garrisoned by a Japanese force estimated to be 600-800 men. The 27th United States Army Division landed 6,500 troops during the assault and met determined resistance until the evening of the second day when the island was brought under complete control. United States casualties numbered 186. 104 prisoners were taken, principally Korean laborers. Apamama island, which was undefended except by a small group of lookouts, was captured by a United States force of 78 men landed from a submarine on the night of 20 November.
Occupation of the Gilbert Islands was supported by approximately 900 carrier-based aircraft which flew 2,278 action sorties in a wide variety of missions, the more important of which were neutralization of enemy air bases, direct support of the landing and subsequent ground operations, interception of enemy air raids and diversionary raids such as the strike on Nauru Island which preceded the landings. These aggressive air operations supplemented by the activities of Army and Navy land-based air from southern bases neutralized Japanese air power in the Gilberts-Marshalls area. The only serious damage from air attack suffered by United States Forces was a torpedo hit on the light carrier Independence which necessitated her withdrawal for repairs. The only serious naval loss was the sinking of the escort carrier Liscome Bay by Japanese submarine torpedo.
United States garrison forces which relieved the assault troops on Tarawa, Makin and Apamama commenced immediate development of these islands for further operations against the Marshalls. By the end of December four airfields were operational, three of which were suitable for heavy bombers. Pressure was maintained on the Japanese bases in the Marshalls, Wake, Nauru and Kusaie by air raids from the steadily increasing force of land-based aircraft and by carrier air strikes on the most important of these bases. The inadequate Japanese land-based air forces in the Marshalls, although reinforced by more than 100 percent, were unable to prevent United States development of strong bases only 300 miles distant, and by December had lost a complete air flotilla, approximately 100 planes, in the attempt.
Build Up And Subsequent Planning
Planning and assembly of forces for invasion of the Marshalls commenced during consolidation of the Gilberts. The Marshall Islands offered at least two alternative objectives, either of which might be chosen in accordance with the directive to seize one advance fleet anchorage and two supporting positions. The Japanese realized that, having determined not to commit their fleet in defense of these islands, they must anticipate the point of United States attack and reinforce it before the attack was launched. One Japanese staff officer when recounting the discussions among members of the Combined Fleet Staff stated: "There was divided opinion as to whether you would land at Jaluit or Mille. Some thought you would land at Wotje but few thought you would go right to the heart of the Marshalls and take Kwajalein." Mille, Wotje and Maloelap garrisons were reinforced. United States Pacific Fleet planners decided to employ superiority in mobile and air forces to strike boldly at the heart of the new area which was to be brought under control.
Forces for invasion of the Marshalls were assembled on the Pacific Coast and in the Hawaiian Islands with a few elements being brought from the Ellice and Samoan Areas. The Fourth Marine Division was lifted from the West Coast between 6 and 13 January and passed through staging points in the Hawaiian Islands. The Seventh Infantry Division, United States Army, mounted in Hawaii. All attack forces left those islands about 22 January in order to arrive at their objectives in early morning of 31 January. Three initial objectives were to be attacked simultaneously: Kwajalein Island and Roi-Namur Islands in Kwajalein Atoll and Majuro Atoll roughly 270 miles to the southeast. Three attack groups composed of 217 ships carrying 63,735 troops were assigned to these objectives. A neutralization group of 7 cruisers and destroyers was employed to bombard Japan's most threatening bases at Wotje and Taroa.
Occupation of the Marshalls
Four fast carrier task groups of Task Force 58, which included 12 carriers, commenced supporting air operations on D-minus-2-day, 29 January 1944. These groups could bring 700 aircraft to bear against the estimated 130 Japanese aircraft distributed among bases in the Marshalls. Simultaneous attacks by this force on fields at Roi, Kwajalein, Wotje and Taroa were so successful in achieving surprise and destroying their targets that by evening on 29 January there was not an operational Japanese aircraft east of Eniwetok.
The Japanese air and submarine efforts to oppose the invasion were negligible, and enemy plans for garrison reinforcement and strengthening of fixed defenses could not be accomplished quickly enough to meet invasion at all points. Simultaneous heavily supported landings well inside the reinforced perimeter islands overwhelmed the defenses within a few days. Roi-Namur Islands were completely in United States hands by noon of D-plus-2-day and 2 days later on 4 February the occupation of Kwajalein Island was completed. Majuro Atoll, the third primary objective was occupied without opposition, the small group of Japanese defenders having abandoned the atoll prior to the United States landing.
The Gilbert and Marshall Islands, extending through an area one thousand miles long and including at least seven Japanese strong points, had been brought under United States control. Continuous operation of United States carrier task forces in the area, unchecked by Japanese land-based aircraft, forced the Japanese Fleet to abandon Truk as a major base. Between 3 and 10 February 1944 all units of that fleet except a few cruisers and destroyers of the Area Defense Forces withdrew to Palau and the Empire leaving United States forces in the Central Pacific unopposed except by garrison troops and a decimated Japanese air force.
It had been planned to seize and develop the strategically located atoll of Eniwetok on 10 May to provide the United States Fleet with an anchorage which would complete the neutralization of Truk and from which large-scale operations against the Marianas could be initiated. The outstanding success of the Marshalls operation and the fact that reserve troops assigned thereto were not needed, allowed rapid preparation for the next offensive. These factors, together with the flexibility of United States planning and fleet organization, permitted the Eniwetok assault to be scheduled for 17 February, 3 months prior to the date originally planned.
Seizure of Eniwetok
An assault force and the necessary supporting forces for the now familiar pattern of amphibious attack were rapidly organized at Kwajalein and sortied for Eniwetok on 15 February 1944. To insure freedom from interference by Japanese air strength at Truk a carrier air strike on that stronghold was planned to coincide with the operations against Eniwetok. The success of this supporting strike is attested by the total absence of any enemy air attacks on our forces operating against Eniwetok.
The amphibious operations against the three most important islands of the atoll, Engebi, Eniwetok and Parry, proceeded smoothly as they were attacked in that order by the experienced air, ship, and assault troop team. Engebi was captured on 18 February after one day of preliminary bombardment from ships and by guns landed on small islands nearby. The capture of Eniwetok and Parry Islands required 5 days, 19 to 23 February. The other less important islands of the atoll were captured during these seven days of operations against the three principal islands. United States fighters were operated from the field at Engebi by 27 February. The total Japanese force present in Eniwetok Atoll was 3,400 men. In its capture United States forces suffered 716 casualties.
Part of the success of this operation can be attributed to the rapidity with which advantage was taken of previous successes at Kwajalein and Majuro. There were many evidences that hasty preparations were in progress for greatly increasing the strength of the defenses at Eniwetok. Many guns ready for emplacement and materials for fortification and beach defenses were found at each objective.
During the operations against Eniwetok, United States carrier task groups struck Truk on 16 and 17 February, Jaluit on the 20th, and the Marianas on the 22d. At Truk the sustained two-day attack by carrier aircraft destroyed 26 merchant vessels, 6 combatant ships, and 270 aircraft, damaged 6 more naval vessels, and inflicted severe damage on fuel and provision storage. It had been planned to strike Ponape and Jaluit next but in view of the success of the Truk operation a carrier strike on the Marianas was substituted.
Carrier Task Force Raids
The carrier task force which attacked the Marianas on 22 February struck this center of the new Japanese defense line in the Pacific at the very time the enemy was making strenuous efforts to reinforce it. Although detected by reconnaissance aircraft 420 miles east of Saipan, the task force fought its way through a night-long series of attacks by land-based aircraft without significant damage and commenced launching the first of a day's strikes next morning. One hundred twenty aircraft, the entire strength of that portion of the Japanese First Air Fleet in the Marianas, were destroyed. The destruction of the advanced echelon of the First Air Fleet was a severe blow to the air organization upon which Japan was depending heavily for the defense of the Marianas and Western Carolines. It was the first of several strikes by carrier task forces which were to prevent the First Air Fleet from ever reaching its full strength and fighting efficiency.
Preparation and execution of the Gilbert-Marshalls Campaign covered the period between August 1943 and March 1944. In that time the United States air-amphibious team, spearheaded by carrier task forces, shattered the Japanese defensive perimeter and brought under United States control an area of 800,000 square miles including numerous islands which provided several large fleet anchorages and many airfields. United States carrier task forces and land-based aircraft had destroyed or rendered impotent all Japanese air power east of the Marianas. The threat of attack by carrier task forces had forced the Japanese Fleet to the extreme western Pacific Ocean. This campaign eliminated Truk and the eastern Caroline Islands as an effective part of the Japanese Pacific defense system. The rapid establishment of advanced operating bases for the United States Fleet made possible the repeated carrier air strikes upon the Carolines and provided the support vital to the Southwest Pacific Forces in New Guinea. It was an essential preliminary to the occupation of the Marianas soon to follow.
United States Sources:
- Commander in Chief, United States Pacific Fleet and Pacific Ocean Areas monthly reports to Commander in Chief, United States Fleet, "Operations in the Pacific Ocean Areas," June 1943 to February 1944, inclusive.
- Headquarter, United States Fleet, reports on Amphibious Operations Gilbert Islands and the Marshall Islands (Cominch P-002).
- Office of Naval Intelligence Statistical Section reports of losses and damage to Japanese naval and merchant ships.
- Reports of the Joint Army-Navy Committee on Assessment of Loss or Damage Inflicted on Enemy Naval and Merchant Vessels.
- Military Intelligence Section, War Department, estimates of disposition and strength of Japanese Forces.
- U.S.S.B.S. Island Studies of Rabaul, Truk, Wake, and the Marshall Islands.
- United States Strategic Bombing Survey Interrogations of:
Nav No. U.S.S.B.S. No. Lt. Comdr. Tokuno (Mille Air Campaign) 18 93 Comdr. Matsuura (Gilbert-Marshalls Shore-Based Air) 30 123 Comdr. Nakajima (Gilbert-Marshalls) 34 139 Capt. Ohmae (Defense Plans, Gilberts and Marshalls) 38 160 Capt. Ohmae (Overall Planning) 43 192 Capt. Shiki (Movements of Japanese 2d Fleet in Central Pacific) 82 396 Admiral Nabeshima (4th Fleet Operations) 96 445 Comdr. Fujimuri (Submarine Operations) 108 466
- Liaison Committee (Tokyo) for the Imperial Japanese Army and Navy replies to U.S.S.B.S. Questionnaires Nav-0, 12 October 1945, Nav-2, 18 October 1945 and Nav-9, 31 October 1945.
- Imperial Headquarters directives.
- War Diary of 22d and 24th Air Flotillas.
Strength of Opposing Ground Forces, Casualties and Japanese Garrison
Strength in the Central Pacific
United States Japan Assult Garrison Location Troops Casualties Troops Killed Prisoners Tarawa 1 15,545 1 3,024 2 4,800 4,654 1 146 Makin 1 6,507 1 186 2 800 696 1 104 Apamama 1 78 1 5 1 20 1 20 0 Total 22,130 3,215 5,620 5,370 250
Strength of the most important Japanese garrisons in
the Central Pacific, 15 January 1944
Garrison Garrison Location Troops Location Troops Eniwetok Atoll 2 1,000 Nauru Island 2 6,000 Jaluit Atoll 2 3,500 Ponape Island 2 5,000 Kwajalein Atoll 2 8,000 Truk Atoll 2 20,000 Maloelap Atoll 2 3,300 Wake Island 2 6,700 Kusae Island 2 4,000 Wotje Atoll 2 3,500 Mille Atoll 2 5,500 Unknown 2 6,000 Total 72,500
1 CINCPOA monthly reports to COMINCH "Operations in Pacific Ocean Areas."
2 MIS, War Department
3 Action Reports, United States Pacific Fleet.
United States Japan KWAJALEIN ATOLL Assult Garrison Location Troops Casualties Troops Killed Prisoners Roi Island 2 3,000 Kwajalein Island 2 3,000 Other Islands 3 2,000 Totals for Kwajalein Atoll 3 42,546 1 1,516 2 8,000 7,710 1 290 ENIWETOK ATOLL Engebi Island 1 251 1 1,200 1 16 Eniwetok Island 1 131 1 900 1 25 Parry Island 1 334 1 1,300 1 25 Totals for Eniwetok Atoll 1 7,997 716 1 3,400 3,334 1 66 Grand Totals MARSHALLS CAMPAIGN 50,543 2,232 11,400 11,044 356
1 CINCPOA monthly reports to COMINCH "Operations in Pacific Ocean Areas."
2 MIS, War Department
3 Action Reports, United States Pacific Fleet.
Extracts from official reports of the Imperial Japanese Government
concerning the Gilbert-Marshalls Campaign
The material contained herein was extracted from the following Japanese reports of the Liaison Committee (Tokyo) for the Imperial Japanese Army and Navy:
(a) Reply to U.S.S.B.S. questionnaire NAV-2, 18 October 1945.
(b) Reply to U.S.S.B.S. questionnaire NAV-9, 31 October 1945.
In some instances the original replies were corrected by the Japanese Government as additional information became available. Questions and answers are indicated by Q. and A.
Q. Make chart or table showing the command organization of Japanese forces, (Army, Navy and Air forces) in Central Pacific, (east of longitude 150° E,) as of 1 November 1943.
(a) Include names of senior commanders and their chiefs of staff.
(b) Show relationship of command between the services (Army, Navy, Air Forces).
A. Organization chart of Japanese Naval Forces in the Central Pacific, east of longitude 150° E., as of 1 November 1943.
Commander in Chief Combined Fleet, Truk
1st Bat Div 2d Fleet 3d Fleet Commandant Commander in Chief Commander in Chief 4th Squadron Commandant 3d Squadron Commandant 5th Squadron Commandant 7th Squadron Commandant 2d Destroyer Squadron
l0th Squadron Commandant
4th Fleet Commander in Chief, Truk 2 14th Squadron Commandant, Truk 1 4th Minor Base Force Commandant, Truk 1 Nagara, Naka 1, 41st Naval Guards, Truk1 Isuzu 3, 42d Naval Guards, Ponape 1 22d Air Squadron Commandant, Ruotto 1 6th Base Force Commandant, Kwajalein 1 22d Air Squadron 61st Naval Guards, Kwajalein 1 3d Minor Base Force Commandant, Tarawa 1 62d Naval Guards, Jaluit 1 67th Naval Guards, Nauru 1 63d Naval Guards, Wotie 1 64th Naval Guards, Moloelap 1 65th Naval Guards, Wake 1 66th Naval Guards, Mille 1
1 Indicates permanent location.
6th Fleet Commander in Chief, Truk 2 SubRon 1 1
2 Indicates the location 1 November 1943.
3 Indicates a warship.
(a) Roster of each commandant, chief of staff, and senior staff officer:
|4th Fleet||Commandant:||Vice Admiral Kobayashi, Hiroshi|
|Chief of Staff:||Rear Admiral Nabeshima, Shunsaku|
|Senior Staff Officer:||Capt. Inouye, Kenichi|
|14th Squadron||Commandant:||Rear Admiral Ito, Kenzo|
|Chief of Staff:||Commander Fupita, Isamu|
|Senior Staff Officer:||Commander Hori Yoshifusa after 4th Nov.|
|3d Minor Base Force||Commandant:||Rear Admiral Shibazaki, Keiji|
|Chief of Staff:||Commander Hori, Yoshifusa|
|Senior Staff Officer:||------|
|4th Minor Base Force||Commandant:||Rear Admiral Wakabayashi, Seisaku|
|Chief of Staff:||Commander Hori, Yoshifusa|
|Senior Staff Officer:||Commander Higuchi, Nobuo after 4 Nov.|
|6th Base Force||Commandant:||Rear Admiral Akiyama, Monzo|
|Chief of Staff:||Capt. Hayashi, Koichi|
|Senior Staff Officer:||Date unknown. Capt. Hirata, Taro.|
|22d Air Squadron||Commandant:||Rear Admiral Kira, Shunichi|
|Chief of Staff:||Commander Matsuura, Goro|
|Senior Staff Officer:||------|
(b) Relationship of Command between Land, Sea and Air Forces:The Naval Commandant (Commander in Chief, 4th Fleet) was responsible for integration of command.
The senior commandants exercised the authority of integrating command in their respective islands. However, as far as air operations were concerned, the air forces took direct orders from Combined 22d Air Squadron; while only in case of cooperating with defensive operations on land, were they subjected to integration of command by the Senior Commandant present on the spot.
Q. Give the Order of Battle as of 1 November 1943 for Japanese forces in Central Pacific as follows:(a) Troops in each island garrison of Makin, Tarawa, and Apamama.A. Order of Battle as of 1 November 1943:
(b) Disposition of aircraft east of longitude 150° E.
(c) Disposition of naval vessels east of longitude 150° E.(a) Garrison strength of respective islands:Makin, about 300;(b) Disposition of aircraft, east of longitude 150° E.:
Tarawa, about 2,000;
Apamama, about 20 (only lookouts).Headquarters:
755th Flying Corps "Chuko" 25
252d Flying Corps Fighter 21
552d Flying Corps "Suisei" 18 (Mille). 801st Flying Corps "Daitei" 8 (Jaluit). 6th Base Force: 952d Flying Corps Patrol seaplane 3
4th Base Force: 902d Flying Corps Patrol seaplane 9 (Truk). (Minor) 3 (Saipan). Total 120
NOTE:--" " indicates the type of aircraft in Japanese name.(c) Disposition of naval vessels, east of longitude 150° E.:Truk:
(Headquarters of Combined Fleet): 1st Bat Div Yamtato, Musashi (Headquarters of 2d Fleet): 4th Squadron Atago, Takao, Maya, Chokai. 5th Squadron Myoko, Haguro. 2d Destroyer Division Noshiro, unknown number of destroyers. (Headquarters of 3d Fleet): 3d Squadron Kongo, Haruna. 7th Squadron Kumano, Suzuya, Tone, Chikuma. l0th destroyer Squadron, a part Yakagi, unknown number of destroyers. (Headquarters of 4th Fleet): 14th Squadron Naka, Isuzu, Nagara. Some other vessels attached to 4th Fleet. (Headquarters 6th Fleet) SubRon 1 18 submarines, approximately. Several subchasers attached to 4th Base Force.
Marshall Islands:1 Mine sweeping Corps, 2 subchaser Corps of 6th Base Force.
Q. Copies or gist of principal operation orders, plans, or directives for defense of Gilbert and Marshall Islands. What were the instructions in effect on 1 November which guided the senior navy, army, and air commanders in their operations in the Central Pacific, (east of longitude 150° E.)?
A. Gist of Operation Plans for Defense of Gilberts and Marshalls effective on 1 November.Q. What were total aircraft losses in Gilbert-Marshall Islands between 1 November - 31 December 1943? Give approximate proportions of combat and noncombat losses?
(a) To detect the foe movement at an early stage by utilizing the lookout organization. (b) By suitable reconnaissance air patrol, to detect the approaching movement of the foe. (c) Should an approaching foe be detected, to destroy the foe on the sea, by repeated counterattacks of all aircraft on the spot. (d) Should foe commence landing, to use every possible means to destroy him at the beach; and preparing for such a situation to complete fortification as soon as possible. (It was almost hopeless to build permanent fortifications because of difficulties in transporting the necessary materials). (e) When the enemy attacked the Gilberts, our operational plans, which had been drawn up in complete form on about 8 September, were as follows: 1. Large submarines in the Rabaul area (and, if possible, small submarines) were to move up and operate in the vicinity of the Gilberts. 2. 2d Fleet was to advance to sea area from west to north of Nauru and decoy the enemy fleet. Then, after 36 land-based attack planes from Rabaul had carried out attacks on the enemy, it (2d Fleet) was to move up to Mille area and continue operations. 3. If necessary, a destroyer squadron was to come up from the Rabaul area and participate in the operations. 4. Planes of 3d Fleet were undergoing training, but even those elements of a low degree of training were to join in these operations depending on the time of the enemy's attack. (f) In spite of the above plans, when the United States forces attacked the Gilberts the 2d Fleet had already suffered great damage at Rabaul on 5 November. Further, due to the increased tempo of operations in the Solomons, the land-based attack plane units and the destroyer squadron which were to have been diverted from that area could not be employed in accordance with plans. There was nothing else to do but get along with the strength then in the Gilberts and Marshalls. Successive reinforcements of air strength from other areas were either not on time or were insufficient in number and we never got back on our feet.
A. Total aircraft losses in the Gilbert-Marshall Islands area between 1 November and 31 December:There are estimated to be about 80 planes, broken down as follows:Q. What aircraft reinforcements were sent into Gilbert-Marshall Islands area between 1 November and 31 December 1943?
"Chuko" About 50 planes. Fighters About 15 planes. Flying boats About 5 planes. Patrol seaplanes About 5 planes. "Suisei" About 5 planes. TOTAL 80
A. Aircraft reinforced to the Gilbert-Marshall Islands area between 1 November and 31 December are as follows:
24 November: 21 land-based attack planes. 25 November: 3 land-based attack planes. 26 November: 12 land-based attack planes. 28 November: 4 land-based attack planes (moved up to H.Q. AirFlot 24). 2 December: 46 (approx.) land-based attack planes. 12 "Tenzans." 37 fighters. Total 135
Q. What changes in disposition of naval vessels in the Central Pacific area east of longitude 150° E. were made and when during period 1 November and 31 December?
A. Changes of disposition of naval vessels in Central Pacific area of longitude 150° E., and the date of the changes:
(a) A surface force, formed around the 2d Fleet for participation in operations in the Solomons and Bismarck Areas, departed Truk on 3 November arriving Rabaul 5 November. On that date, however, it underwent an air attack by a United States carrier task force and sustained serious damage. It departed Rabaul the same day, returning to Truk. Subsequently a considerable number oŁ ships required repairs. From that time on, surface strength at Truk was seriously weakened. (b) There was a plan in existence to reinforce the garrison strength of Makin by transporting about 1,500 Army troops to that island. The troops were loaded on 4th Fleet's Nagara, Isuzu, and 2 destroyers, which departed Truk about 19 November. Due, however, to the commencement of strikes on the Gilberts by United States carrier task forces, the troops were eventually diverted to reinforcement of the Marshalls although the possibility of making counterlandings on Makin had once been under consideration. The ships arrived at Mille about the 22d or 23d, and landed the troops there. (c) On about 24 November, 2d Fleet (participating elements unknown) sortied from Truk and proceeded to Kwajalein, subsequently moving to Ruotto, where items of cargo were landed. They then sailed on the night of 3 December and returned to Truk. (d) No sortie of fleet in strength was made in connection with United States raids on the Gilberts. Q. Give the disposition of air strength in the area to the east of longitude 150° E. on 25 January 1944.
Answers to U.S.S.B.S. questionnaire NAV-9 dated 15 October 1945.
A. Marshals Area: Ruotto HDQ Air Flot 24
Air Group 752
Air Group 753
Air Group 281
12 land-based attack.
3 land-based attack.
Taroa Air Group 252
Air Group 752
9 land-based attack.
Wotje Air Group 531
Comdr. of Air Group 80
Kwajalein Group 952 10 float reconnaissance. Eniwetok Air Group 753
Air Group 752
9 land-based attack.
6 land-based attack.
Truk Air Group 204
Air Group 902
Air Group 755
About 50 fighters.
About 10 float reconnaissance.
About 8 land-based attack.
Marianas: Saipan Air Group 201
Air Group 802
Air Group 902
HDQ. of 4th Fleet and of Air Flot 26.
About 30 fighters.
About 5 flying boats.
About 4 float reconnaissance.
Tinian HDQ. of Air Flot 22.
Air Group 755
18 land-based attack.
Q. List naval vessels in waters to the east of longitude 150° E. on 25 January 1944.
A. Truk: Bat Div 1 Musashi 2d Fleet: CruDiv 4 Atago, Takao, Maya, Chokai CruDiv 5 Myoko, Haguro DesRon 2 Noshiro, several destroyers. 3d Fleet: BatDiv 3 Kongo, Haruna CruDiv 7 Kumano, Suzuya, Tone, Chikuma CarDiv 2 Junyo, Hayataka, Hiyo, Ryuho l0th Div Yahagi, several destroyers. 4th Fleet: 14th Div. Naka, Isuzu, Nagara Several ships and boats attached to 4th Fleet. Several subchasers attached to 4th Minor Base Force. 6th Fleet: Katori, SubRon 1 and SubRon 8 Marshall Islands: 1 mine sweep unit and 2 subchaser units attached to 6th Base Force.
NOTE--Of the above listed ships, a considerable number should have been in home waters undergoing repairs.
Q. Give gist of principal operation orders, plans or directives for defense of the Marshall Islands.
A. (1) Make every effort to prevent enemy invasions and occupations, at least to the extent of inflicting the maximum damage on him. (2) Dispose air strength in depth and concentrate air attack strength at rear bases. By doing this it will obviate being surprised even though information gained from patrols is scanty. Plan to use bases at Eniwetok and Wake as much as possible. (3) Plan to use surface craft at Truk in urgent transportation operations and do not expend them in decisive naval actions.
Q. What aircraft losses were sustained in the Inner South Seas Area east of longitude 150° E. between 1 January and 1 March 1944?
A. (1) January, about 100 planes. (2) February, about 430 planes. (3) About 340 planes were damaged at Truk on 16-17 February.
Q. What aircraft reinforcements were sent to the Inner South Seas Area between 1 January and 1 March 1944?
A. 1st Air Fleet, about 600 planes. 25th Air Flotilla, about 160 planes. 26th Air Flotilla, about 150 planes. Air Group 551, about 24 "Tenzan" planes. Air Group 851, about 6 flying boats. Total about 940 planes.
Q. What losses or severe damage to naval and merchant vessels occurred in the Inner South Seas Area between 1 January and 1 March 1944?
A. (a) Naval Vessels: 13 Jan.: Wotje: Patrol vessel Sunk by B-25 strafing attack. 17 Feb.: Truk: Naka (CL 17) Sunk during carrier air strike. Katori (CL(T)1) Oikaze (DD-2) Tachikaz (DD-11) Fumitsuki (DD-30) Maikaze (DD-103) Shigure (DD-60) Severely damaged--carrier air strike. Harusame (DD-70) Akikaze (DD-7) Nowake (DD-100) Akashi (AR-2) Hakachi (Target Ship) (b) Merchant Vessels: 11 Jan., Kwajalein: Ikuta M. Sunk by 10 B-24s, low level attack. 13 Jan, Wotje: Transport Sevely damaged by B-25's strafing. 17 Feb., Truk: 26 MVs Following "Maru's" sunk during carrier air attack: Hoki, Aikoku, Shojin, Reiyo, Heian, Riyo, Seiko, Hoyo, Seicho, Teikichi, Soko, Nagano, Amagisan, Fujisan, Zuikai, Rio De Janeiro, Dai San Tonan, Yamashimo and Akagi, plus 5 other unidentified ships.
Q. What changes in plans were made as result of carrier task force strike on Truk, 16-17 February?
A. Truk became unsuitable as a fleet anchorage. Because of this and also because of heavy losses to supply ships, the Combined Fleet decided to fall back. Since it had lost much of its mobility, it became exceedingly difficult to make use of the fleet in an aggressive manner during the defensive operations of the Marianas.
Q. Give the disposition of Japanese air strength in the Marianas on 20 February 1944.
A. Saipan: 30 Type 0 ship-based fighters; 10 Suiseis. Tinian: 40 Type 1 land-based attack planes; 10 Gekkos. Guam: 5 Type 0 land-based transports.
Q. What were the losses of Japanese aircraft during the carrier task force strike on the Marianas, 22 February 1944?
A. (1) From United States carrier based air attacks 40 (2) From aerial engagements 20 (3) Destroyed on the ground 30 (4) From other causes (Chiefly from faulty landings and take-offs at night) 5
Q. What damages to land installations and personnel casualties resulted from this carrier aircraft strike?
A. (1) Majority of hangars and part of the living quarters were destroyed by fire. (2) Personnel casualties numbered about 300 (of which about 250 were airplane crews).
Q. What was the effect of this attack on operations in defense of the Marshalls and the Inner South Seas Area.
A. As a result of the strikes on Truk by the United States task force, it was decided that the 1st Air Fleet, which at the time was undergoing training in the homeland, be put in the Marianas. The advance echelon had arrived in the Marianas on 20 February, just in time to have its protruding nose flattened. This became the weak point in the disposition of the 1st Air Fleet and before its strength could be brought up to a point where some confidence could be placed in it, the various units in the Inner South Seas Area were subjected to separate attacks.
Q. What changes were made in plans of operations orders for defense of Inner South Seas Area between 1 January and 1 March?
A. (1) After about 10 February the standby area for the main strength of the Combined Fleet was changed to Palau Area. (2) After about 21 February all the air strength in Rabaul Area was transferred to Truk to assist in defense of that area. (3) Gist of orders to the various commanders on 1 March 1944: (a) With the forces available defend the Marshalls and Truk to the death. (b) Endeavor to destroy the enemy forces by using air forces of the remaining bases at Truk, Wake, Nauru, and Marshalls. (c) Regard Truk as the outpost of the Marianas and Palau and always keep a strong aircraft patrol force there so as to be able to reconnoiter the enemy.
Significant Movements of Major Japanese Naval Units
In Central Pacific Between 1 NOV 1943 and 10 FEB 1944