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Interrogation Nav 50, Commander J. Fukamizu

31 Oct 1945


FUKAMIZU, J. Commander, I.J.N.

FUKAMIZU served 17 years in the regular Navy. From December 1941 until June 1942 he was a supply officer on the staff of the 21st Air Flotilla. For the next six month, FUKAMIZU was attached to the staff of the Southwest Area Fleet also as a supply officer. Thereafter until the end of the war, he was in charge of the 1st Section of the 1st Department of Naval Air Headquarters, TOKYO, which was charged with the allocation of aircraft to tactical and training commands at the direction of the Naval General Staff. FUKAMIZU answered questions frankly and directly, and was considered a very reliable source of information.

Supply Officer, Staff 21st Air FlotillaDecember 1941-June 1942
Supply Officer, Staff Southwest Area FleetJuly 1942-December 1943
Chief, 1st Section, 1st Department, Naval Air HeadquartersTOKYOJanuary 1943-August 1945



31 OCTOBER 1945-1 NOVEMBER 1945

Interrogation of: Commander FUKAMIZU, IJN, who was in charge of the First Section of the First Department of the Koku Hombu, concerned with aircraft distribution records from January 1943 until the end of the war.

Interrogated by: Lt. Cmdr. R. P. Aikin, USNR.

Allied Officer Present: Lieut. R. C. Garred, USNR.


Commander FUKAMIZU had prepared a graph on which were plotted: (1) Annual overall naval aircraft production and wastage totals from December 1941 to August 1945. (2) Annual naval aircraft production and wastage totals by plane type, i.e. fighters, bombers (torpedo and dive), medium-bombers, Baka, float planes, flying boats, land-based reconnaissance planes, trainers and transports. (See Annex A) Commander FUKAMIZU also had prepared a chart breaking down wastage totals by (1) Months from December 1941 to August 1945. (2) Cause, i.e. combat and non-combat losses and (3) Principal campaigns. The monthly totals coincide with those plotted on the graph. (See Annex B) The attached interrogation conducted over a two day period established the basis on which the graph and chart were prepared.


Q. Did you assemble the reports yourself?
A. Yes. An assistant helped me prepare the chart on monthly losses, but the production and loss graph I made myself.

Q. Is the monthly loss chart the official reply to Nav. Memo. No. 18 submitted through the Navy Liaison Office?
A. No. I understand that is being prepared by officers in the GUNREIBU.

Q. Are you familiar with aircraft production figures as well as losses?
A. No. I accepted Capt. TERAI's (GUNREIBU) figures on production. (Note: Aircraft production totals graphed coincide exactly with data furnished FEAF by GUNREIBU officers and published in FEAF Intelligence Memorandum No. 22; the production totals also are the same as those furnished FEAF -- see Intelligence Memorandum No. 28 -- by General Endo, former head of Air Ordnance Bureau of the Ministry of Munitions. The latter figures are the same as those given to Comdr. Paul Johnson.)

Q. How did you prepare the loss reports?
A. On the basis of periodic plane availability reports received at least monthly and occasionally more often, from the Air Fleets and their subordinate commands.

Q. Do you have these reports?
A. No, they were burned.

Q. Then, how could you construct the graph and chart of losses?
A. I know the exact strength by plane types of the Japanese Naval Air Force at the beginning of each fiscal year (April) and also the exact monthly production as well as the approximate losses during each campaign and major action.

Q. What was the purpose of the Air Fleets and their subordinate commands sending by dispatch and mail-plane availability and loss reports to the First Section of the First Department of KOKU HOMBU?
A. They were sent to my department for two reasons: (1) To make the figures of losses available to the Minister of the Navy, and (2) in order to carry out my duties. When the GUNREIBU directed the General Affairs Department (SOMU BU) of the KOKU HOMBU to supply tactical and training units with aircraft, it was the function of my department to determine from what source such additional aircraft were to be obtained, i.e. civilian factories and/or naval arsenals, depots or other tactical or training commands. Accordingly, to accomplish its mission, my section was furnished with monthly and other periodic plane availability reports of all tactical and training commands. This was necessary so that we could know from what source aircraft would be available for supply to tactical commands.

Q. Regarding your loss and production chart, how were the exact loss figures, shown on the graph, obtained?
A. We know the exact annual production figures throughout the war and the exact strength of the IJNAF at the end of each fiscal year (31 March). By subtracting the total strength at the end of the fiscal year from the sum of the same figure for the start of the preceding year and the total year's production, we arrive at an exact annual loss figure.

Q. Do the production figures represent actual acceptances by the Navy?
A. I don't know. However, it is my opinion that only planes actually accepted by the Navy are included in the production figures. During the first part of the war, all planes produced were considered Navy acceptances. This practice was found to be unsatisfactory and was abandoned in 1944 -- August, I believe. From then on, only accepted aircraft are used in the production figures.

Q. Why did you change your system of figuring production totals?
A. There was approximately a 30-50 percent discrepancy between the monthly aircraft factory production figures and the actual number of aircraft the Navy accepted.

Q. What were the reasons for the rejections?
A. Aircraft were not accepted when they failed to meet Navy specifications. There were some minor defects, modifications, adjustments, additional equipment to be added (belly tanks for over-water ferrying) etc. Some of the aircraft had to be returned to the factory for as long as a month to correct these deficiencies.

Q. How were these rejections listed in your availability reports?
A. Such aircraft were not subsequently included in the following month's factory production figures. However, at the end of the fiscal year in March, rejected aircraft were deducted from that month's aircraft production figure in order to close the yearly records and carried over into the following fiscal year.

Q. Do production figures include both aircraft produced by Navy arsenals and civilian factories?
A. Yes, both are included.

Q. The 1944 production is graphed at 14,178 aircraft, whereas previous information obtained from the GUNREIBU and Munitions Ministry shows a total of 13,418. Which is correct?
A. The lower figure does not include the OKA (BAKA Bomb).

Q. Were aircraft requirements, established by GUNREIBU, generally met?
A. In the majority of cases, the factory orders were not fulfilled in the specified time limit. After U. S. bombings became intensive, this situation worsened. Generally speaking, orders for standard aircraft models (ZEKES, KATES etc.) were more easily met. Orders for the newer types, (FRANCES, MYRT etc.) were often 30 to 50 percent incomplete by the time specified in the contract.

Q. What is your estimate of in-transit losses of aircraft being ferried from depots to tactical units?
A. Approximately 3 to 5 percent throughout the war. In the early part of the war, the great distances to outlying bases was the main factor in ferrying losses. Toward the end of the war the distances to bases were shortened but flight personnel were less experienced. The percentage of losses remained fairly constant.

Annex "A"

[See image]

Annex "B"

Japanese Naval Aircraft Losses
Dec '41 to Aug '45

Aircraft Expended in Greater East Asia War
Plane TypeFiscal 1941Fiscal 1942Fiscal 1943Fiscal 1944Fiscal 1945Grand
Fighters 44/3235/3431/3826/60136/16436/3557/47137/70103/05104/6136/54120/5784/6648/7047/6425/7325/76822/76865/9540/10173/11493/132108/113134/125112/184149/155124/13080/183102/15490/1871170/167350/12360/206370/16546/8634/19070/220210/275295/297110/34095/23085/200148/2451593/2577335/260175/220140/230180/320160/400990/14304691/6612
Torpedo & Dive Bombers19/2411/2315/268/2053/9319/1090/8189/1249/1123/1213/8103/1258/1210/107/938/1532/12631/13113/1523/2526/4130/4830/7160/8240/3670/8125/7710/8622/12118/81367/82420/7260/190220/10520/13140/13530/104120/80100/16050/11520/9533/10080/70793/1357105/9535/10081/11040/12050/200311/6252155/3030
Medium Bombers 25/1111/2140/255/3781/10111/1421/169/1842/1046/1624/1425/1330/1718/1523/1321/1621/12291/1748/2726/3628/5720/5115/5130/4124/7852/5820/6423/814-/5320/66306/66325/8525/7098/4425/7514/7044/8091/6080/7244/8026/9024/7749/88545/89140/7530/5045/9060/9050/110225/4151448/2244
Recce              1/0  1/0   1/30/20/01/30/20/00/00/00/02/102/35/612/84/94/66/819/916/88/67/85/69/797/8418/1113/168/1411/1515/2965/85165/179
Transports 0/40/50/50/60/203/20/22/41/32/31/41/43/31/41/33/32/220/374/31/20/32/43/12/42/34/43/32/42/50/325/394/88/85/94/106/73/814/710/416/67/58/59/794/8412/711/614/77/108/1052/40191/220
Float Planes 2/1115/913/1513/1543/506/1038/1311/1434/1732/1739/1439/1726/137/1210/1313/1620/14275/1015/1925/219/1715/3217/2416/2212/3615/325/328/2715/3212/34164/32815/1632/6770/2815/3220/3121/4735/5976/4725/2728/3215/5822/52374/49620/7624/7635/8056/9064/89199/4111055/1455
Flying Boats 1/50/50/61/42/201/21/12/00/411/20/20/21/20/00/32/42/320/252/30/01/52/52/43/51/43/31/50/54/50/519/492/37/514/51/22/34/88/59/53/31/32/24/457/484/93/84/107/118/1026/48124/190
Trainers 0/180/210/270/260/920/240/200/210/220/270/270/300/300/360/362/342/394/3401/303/451/500/400/330/600/550/610/670/720/800/975/6900/700/800/850/820/1000/10025/11015/10510/877/10015/9550/124122/113880/11060/10070/110120/14080/100410/560541/2820
Total 91/11272/11899/14253/168315/54076/97207/107350/139229/162214/138113/123288/135202/14384/14189/141104/161104/1582064/1645108/192118/230138/287163/315175/299245/339192/459293/396178/378123/458185/450140/4732058/4276118/380197/632789/632115/427120/542178/575522/605601/690266/664191/563187/543371/5973655/6675614/643351/576397/651481/796435/9482278/361410,370/16,750
Notes: 1234 56789101112 131415 16 17181920212223 24    2526 27282930  31 32 33   

NOTE: Number of Planes Expended = Combat Losses/Operational Losses


1. Malaya, Philippines, Hawaii.
2. Malaya, Philippines.
3. Java, Singapore.
4. Ceylon, Surabaya, Batavia.
5. Port Darwin, Bataan.
6. Darwin, Coral Sea.
7. Midway, Aleutians.
8. Attack of Port Headland.
9. Guadalcanal, 1st & 2nd phase Solomons.
10. Guadalcanal Operation.
11. South Pacific Naval Battle.
12. 3rd phase Solomons
13. 1st phase Rennel.
14. Off Isabella, 2nd phase Rennel.
15. Attack on Oro Bay.
16. New Guinea, Oro Bay, Florida Islands.
17. Air battle off Lunga.
18. Kula GUlf, Kolombangara, Rendova.
19. Defense of Munda, Vella Lavella battles.
20. Attacks on Rabaul.
21. Attacks on Rabaul.
22. 1st to 4th attack on Gilberts, Rabaul and Bougainville air battles.
23. Attack on Marshalls, 6th air battle at Bougainville.
24. Landings on Kwajalein and RUDT attacks on Marshalls.
25. Saipan operations.
26. Attack by China-based planes, Tinian landing.
27. Landings on Peleliu and Morotai.
28. Air battles of Taiwan.
29. Defense of Leyte, Battle off Philippines.
30. Defense of Philippines.
31. Defense of Okinawa & Iwo Jima, attack on homeland by Task Force.
32. Defense of Okinawa.
33. Losses to B-29's and shipboard planes. ww2dbase

Source: United States Strategic Bombing Survey (Pacific) Interrogation of Japanese Officials [OPNAV-P-03-100], courtesy of ibilio Hyperwar Project
Added By: C. Peter Chen


Annex A of the interrogation of J. Fukamizu, 31 Oct 1945; Japanese aircraft production and wastage during Pacific War

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Annex A of the interrogation of J. Fukamizu, 31 Oct 1945; Japanese aircraft production and wastage during Pacific War

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