Interrogation of: Lieutenant (junior grade) OKUNO, Y., IJN; naval aviator in a squadron responsible for convoy escort and anti-submarine operations.

Interrogated by: Captain Steadman TELLER, U.S.N.

Allied Officers Present: None.


OKUNO received 70 to 80 hours flight training then was ordered to an operational squadron engaged in protecting convoys from submarine and air attack in FORMOSA vicinity and along the ASIATIC Coast. He had limited experience in the use of radar and magnetic detector. Increasing severity of air attacks by land based aircraft reduced the strength of his squadron and finally forced its withdrawal from the area in April 1945. In May 1945 all air crews of his squadron were incorporated in the Fifth Air Fleet and their aircraft were prepared for Kamikaze attacks.

Q. What was your experience in FORMOSA between December 1944 and February 1945?
A. There were many air raids particularly by B-24's. The most effective weapon used was the anti-personnel fragmentation cluster which caused many casualties among military and civilian personnel and damaged a number of aircraft at the TOKO Base. I was engaged in flying a seaplane for anti-submarine coverage for convoys between FORMOSA and PHILIPPINES. We would use both radar and the magnetic detector. Usually the radar plane was sent out first to search the area and if any indication of a submarine was found, the MAD plane would be called out. I think we had some success with the MAD and damaged two or three submarines in this area, but it was not my own personal experience. On one occasion at night time; the MAD in my plane indicated a submarine, I dropped the float light and on the second pass bombed the float light. On return to base I was told that a sunken hulk was bombed which must have been the one sunk by a U. S. submarine near the BATAN Islands.

Q. How were anti-submarine operations conducted by your squadron along the South CHINA and INDO-CHINA Coast?
A. The squadron was divided among bases stretching from TANSUI, FORMOSA to SAIGON, INDO-CHINA Coast. This coast line was divided into five areas of responsibility, each of which was covered from a base by one unit. The unit at TANSUI covered the area north of FORMOSA. Each day, the unit assigned an area of responsibility would patrol that area if a convoy was scheduled to move through. If no convoy was scheduled, no patrol was flown but training of flying was held. The procedure in searching was to use radar because after autumn of 1944 practically all Navy planes were so equipped. The MAD equipment was not normally used for search, but was used after radar or some other method had located a submarine. Furthermore the supply of MAD was limited and the installation in airplanes required the removal of all machine guns and other large steel objects. The MAD equipment was heavy and caused the plane to be overloaded. There were a few fighters, Type Zero, Navy, assigned to the First Escort Fleet Air Squadron. Five or six were stationed at HONGKONG and six or eight at SANA, HAINAN. Army fighters were not called on for help principally because communication between Army and Navy air units was poor and also because of poor cooperation between the services and the poor performance of Army fighters when flying on sea missions. There was, however, one principal method of cooperation between the armed forces and that was supplying fuel and some repair at each others' bases. By April 1945 all the fighters of this group were either lost or out of commission.

Q. What type of aircraft were you qualified to fly?
A. All single-engine Navy planes except fighters.

Q. What was your experience in aircraft losses in this convoy escort?
A. We lost quite a number of pilots, both on the ground and in the air, to B-24 attacks. Some of these B-24 attacks were formation attacks and others were single search planes from the PHILIPPINES. We could usually tell the time of day that the single plane would come over and would not fly at that time. The single B-24, however, if they caught us over the convoys was very dangerous because it was very maneuverable. We examined the B-24 search plane which was shot down at AMOY in March 1945 and rescued equipment, code books, emergency radio and supplies by diving for them.

We found none of the crew. We thought that the equipment in this B-24 was particularly fine and that the pilots had very good preparation for their work. We noticed that B-24 single planes would sometimes call for help from


their fighters. Our voice radio set was not powerful enough to call for help from the base. We could talk direct by voice radio to the flagship of the convoy if preparation had been made, but only for a distance of five or six miles. Beyond that distance we would have to send by key.

Q. Do you know of air attacks on convoys in your area?
A. On about 4 April 1945 a convoy consisting of the KINE MARU a 5,000 ton transport, escorts vessels Nos. 1, 5, 36, 130 and 134 and two subchasers left HONGKONG for the north. This was called the 11th Convoy Group. Off SWATOW the convoy was attacked for a long time by many B-24's coming from the PHILIPPINES and protected by P-51's from CHINA. The Kine Maru which was carrying civilian personnel from SINGAPORE and military personnel from HONGKONG was sunk. 70 were saved and 240 military personnel lost. Escort vessels Nos. 1, 5, 130 and 134 and one subchaser were sunk at this time.

The most famous sinking in our area was the Asama Maru (large ex-NYK liner). She was sunk in January or February 1945 near PRATAS Reef by a submarine after two days chase. The weather was bad and none of our planes could be sent out in response to her calls for help.

On PRATAS Reef a 30-40 man communication and weather observation unit was maintained. In February or March 1945 a submarine shelled the station and killed the senior officer. Shortly afterward the station was abandoned and personnel evacuated.

Q. To what organization did you go when you returned to KYUSHU?
A. I went to the Fifth Air Fleet in May 1945 and was stationed at OMURA and FUKUOKA. I believe that all the pilots of the First Escort Squadron returned to KYUSHU about this time. This change was the result of an order by the General Headquarters of the Combined Navy Force, the Supreme Headquarters of the Navy. While at KYUSHU our planes and pilots were used on anti-submarine patrol between KYUSHU and KOREA, particularly to prevent American submarines from entering the JAPAN SEA. However, about June we knew that two of your submarines finally entered the JAPAN SEA. During this period, also, our planes were being converted to take 800 k.g. bombs for Special Attack Corps purposes. This was a difficult conversion and about 1/3 of the seaplanes had been completed in conversion at the time the war ended.


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