TOKYO 12 October 1945
Interrogation of: Commander OKUMIYA, Masatake, IJN, Class 1927, I.J.N.A. On Air Staff and Commander RABAUL Air Group 1942 - 1943.
Interrogated by: Captain C. Shands, USN.
Allied Officers Present: Commander T. H. Moorer, USN.
SANTA CRUZ: Composition of Japanese Second and Third Fleets, which were operating just north of the SOLOMONS to (1) support Japanese landing on GUADALCANAL, 13-23 October 1942, and (2) to intercept U.S. troop convoys to GUADALCANAL and U. S. Carrier Task Force. In carrier duel on 26 October, SHOKAKU, ZUIHO and CHIKUMA were damaged. Heavy Japanese air losses contributed to weakening defense of SOLOMONS.
SOLOMONS: GUADALCANAL an intermediate step in southern movement. Main action in SOLOMONS Campaign considered (1) GUADALCANAL (2) MUNDA (3) VELLA LAVELLA (4) EMPRESS AUGUSTA BAY. Inability to hold SOLOMONS attributed to U.S. Navy sea and air action in SOLOMONS Area and lack of landing barges. Heavy-bomber raid on airfield more effective than carrier raid. Carrier raid most effective on aircraft and shipping. RABAUL and TRUK neutralized due to inability to supply. Employment of submarines to supply isolated garrisons considered poor policy. Mining of RABAUL a deterrent to submarine supply operation. Aircraft pilot reports of damage inflicted on enemy always optimistic and only used for newspaper publicity. Staff planning used pessimistic estimate.
Q. Do you know how the RYUJO was sunk in the battle of 23-25 August 1942?
A. It was by carrier dive-bomber and torpedo planes about 25 August. The SHOKOKU, ZUIKAKU and RYUJO were in the SOLOMONS at this time. About the 24th, the carrier RYUJO, the heavy cruiser TONE, and 3 DDs were attacked near GUADALCANAL. They didn't know the source of the dive-bombers and torpedo planes but they were carrier type and came from the direction of GUADALCANAL. Perhaps one destroyer was also sunk.
Q. Are you familiar with the Battle off SANTA CRUZ, 25-26 October 1942?
A. I was there and am familiar with it. I was on the Air Staff of the 2nd Flying Squadron.
Q. What ships were involved?
A. Composition of Japanese Fleet at SANTA CRUZ, 25-26 October. 1942
Second Fleet Vice Admiral KONDO, N., Commander in Chief 1 (CV) JUNYO 2nd Flying Squadron 2 (BB) KONGO, HARUNA 3rd Flying Squadron 4 (CA) ATAGO, TAKAO, CHOKAI, MAYA 4th Flying Squadron 2 (CA) MYOKO, HAGURO 1 (CL) JINTSU (?) 12 (DDs) Third Fleet Vice Admiral NAGUMO, C., Commander in Chief, and commanding whole fleet. 3 (CVs) SHOKAKU (F), ZUIKAKU, ZUIHO 1st Flying Squadron 2 (BBs) HIEI, KIRISHIMA 11th Squadron 2 (CAs) SUZUYA, KUMANO 7th Squadron 2 (CAs) TONE, CHIKUMA 8th Squadron 1 (CL) 12(DDs)
Q. Was the HIYO in the action?
A. No. HIYO had engine trouble at TRUK. The JUNYO was alone in Second Fleet, but I don't believe it was near enough to get in any action.
Q. Did any of the pilots and planes that survived the Battle of MIDWAY come down into the SOLOMONS?
A. In the MIDWAY Battle there were a great many survivors. Because our pilots were in the air when carrier sank, they were rescued by destroyers. Most of the MIDWAY flyers were put on the carriers SHOKAKU, ZUIKAKU and RYUJO. The pilots left from MIDWAY were familiar with carrier operations so put them on these carriers.
Q. What was the mission of the Task Force that was operating in that area?
A. It was a support for the landing operations on GUADALCANAL, scheduled for between 13th and 23rd October.
Q. Did the action of the SANTA CRUZ Battle have any effect upon the landing date?
A. I heard landing was completed on the 25th but that the results were not as successful as expected.
Q. Did that action have any effect on the 14 November night battle?
A. No. The Task Force went back to TRUK on 30 October after SANTA CRUZ Battle, reorganized, then came the 14 November action. Do not know if it affected the plans. Only the 2nd Flying Squadron's planes engaged at SANTA CRUZ, so they had planes during the time of the November action.
Q. What carriers were damaged at SANTA CRUZ?
A. SHOKAKU received four bomb hits on port side amidships and two at the after elevator. The ZUIHO received one bomb hit near the after elevator. The cruiser GHIKUMA got five bomb hits. The destroyer TERUTSUKI got a near miss by a United States flying boat about midnight after the battle. When TERUTSUKI was bombed, the Japanese knew American planes were near the fleet so the Japanese carriers continued to retire northward. Some cruisers and battleships stayed near scene of battle and saw your carrier burning. I saw it from the air. They proceeded to Truk.
Q. Do you know how long after sunrise the first hits were made?
A. The ZUIKAKU was hit about two hours after daylight, about 0830. The SHOKAKU was hit later, about 40 minutes after the raid of Japanese airplanes had departed.
Q. Were any airplanes aboard the carrier when hit?
A. No, all off in attack group except about 16 planes in the fighter cover.
Q. Did those planes come back to the SHOKAKU later?
A. No, they couldn't land on board. They went to the ZUIKAKU and ZUIHO.
Q. How many planes did the aircraft carrier normally carry?
SHOKAKU ZUIKAKU ZUIHO JUNYO VF 27 27 21 18 VB 27 18 18 VT 18 18 6 9 72 63 27 45
About 2/3 were lost. Total lost about 100.
Q. How many planes were involved in the operation from the carriers?
A. About 176. There were three waves. They all went out in the first wave; fewer planes in the second raid, about 60; then in the third wave about 30.
Q. Was the MYOKO or TONE hit by bombs?
A. I think not, but there were near misses. I am not certain. An awful lot of torpedoes came but no hits. In my opinion it was a heavy attack.
Q. Were any horizontal-bombers involved in this attack?
A. About ten B-24s, but the Japanese fighters drove them away so were not attacked. Late at night we received a torpedo attack from possibly, a B-24, but we were able to avoid it by evasive action.
Q. Where did the damaged ships go?
A. All went to TRUK. Then the SHOKAKU, ZUIHO and CHIKUMA returned to JAPAN for repair. It took about 3-4 months to repair the SHOKAKU.
Q. Were any other cruisers or battleships hit?
A. I didn't hear that they were.
Q. When did you receive first information of our carrier Task Force?
A. When south of the GILBERTS, north of HEBRIDES. The Japanese headquarters at TRUK knew of a convoy of transports and battleships approaching GUADALCANAL from the southeast about the middle of October. They believed United States Navy convoy would be about lat. 14ƒS, 191ƒE on chart, south of GUADALCANAL. The Japanese carrier force didn't think so since they knew our search planes from GILBERTS had sighted an American carrier approaching from the east. Japanese carrier force was supposed to attack south convoy but hesitated to do so. Because of radio silence this information was not sent to TRUK. Communication difficulties. TRUK did not know of American carriers. So the Second and Third Fleets waited north of GUADALCANAL while your carriers approached. Our carriers were familiar with position of your carrier force the entire time although TRUK did not have the information regarding position of our carrier force. Our force hesitated about how far south to go. The thing that decided it was your approach. One of our scout planes, scouting on bearing 098ƒT, saw your carrier force in the morning of the 26th. He was supposed to scout 260 miles southeast and 100 miles north.
Q. Did you have submarines in the vicinity?
A. I think they were farther south.
Q. Did you have any report that your planes had damaged or sunk our carriers?
A. There was a report from the planes that an ENTERPRISE class carrier was hit, maybe two. The reports did not come in clearly. We were sure that one was sunk because we saw it, but we didn't get complete reports on the second carrier. Became less certain while waiting for reports that did not come in.
Q. Were any of your pilots instructed to carry out suicide attacks on our carriers?
A. No orders were given; but two of them, on their own initiative, did so. The commander of one wing was one of those that made a suicide dive-bombing attack.
Q. You say a large formation of bombers attacked in the afternoon of the 26th, but no hits were made; is that correct?
A. The statement is correct.
Q. Did the Second and Third Flying Fleets come down the night of the 26th to pursue our ships?
A. Some of our fast ships approached scene of battle but turned back when your burning carrier was sighted.
Q. What were the plans for establishing bases in the SOLOMONS? Where were your principal bases to be located?
A. RABAUL was principal base. GUADALCANAL was an intermediate step for going south.
Q. What interrupted the completion of that plan?
A. I think that sea and air force of the United States Navy. The fact that Americans landed and were able to hold at GUADALCANAL.
Q. While the Americans held GUADALCANAL, were Japanese naval pilots or Army pilots employed in the raids at GUADALCANAL?
A. Almost entirely naval. Few scout planes of the Army. Attacking was done by Navy planes. Navy personnel came first and were land-based. After the sinking of the RYUJO, they added more Navy to them. They also came to BUKA in September.
Q. Why were the reinforcements of GUADALCANAL sent down in small units instead of one mass attack?
A. Didn't have enough landing barges to make a landing. The main point of difficulty in our landing operations was the lack of landing barges. Boats and destroyers were used for landings. But we didn't have enough barges to begin with. Had plenty of big ships but not enough landing craft. Damage from American planes made it worse.
Q. What battles did you consider the principal action in that SOLOMONS Campaign?
A. We considered it all the same thing, but most important was GUADALCANAL, MUNDA, VELLA LAVELLA, EMPRESS AUGUSTA Bay.
Q. Did the bombing of the SOLOMONS airfield effect operations?
A. They got our field completely at MUNDA. We had about 20 planes there which did a very good job in the first battle; but when they landed one day to refuel, they were done in by American fighters. Because of bombing and strafing we couldn't repair or develop the field afterwards. We had only one site at MUNDA. We could only use KOLOMBANGARA for communication. I was at BUIN the toughest part of the time. At BUIN, at the beginning, the Americans used too small bombs. Even at the worst we were still able in the early days to continue to use the field because the bombs used were too small.
Q. What type planes dropped the bombs?
A. B-24, B-25, B-17, and dive-bombers. From August 1943 the big bombers came over from RUSSEL Island. Some times we received five attacks in one day. Because of the damage of BUIN at the end of August 1943, we alternated between BALLALE and BUKA; and by September despite building of an auxiliary field, at BUIN, the BOUGANVILLE Area became impractical for air operations. All planes and personnel retired to RABAUL. After the fighter planes had left BUIN, all resupply was practically impossible.
Q. Did the ground troops remain on BOUGAINVILLE?
A. Yes, the troops brought from GUADALCANAL went up to BOUGAINVILLE Island from all the SOLOMON ISLANDS. Remaining infantry troops gathered at BUIN.
Q. How did they travel between the islands?
A. January 1943 by destroyer. They evacuated GUADALCANAL with 20 destroyers. MUNDA, RENDOVA and VELLA LAVELLA troops were also evacuated by destroyer. The closer islands were evacuated by submarine and very small boats.
Q. Do you know about any losses of any ships; for instance, KINUGASA and KIRISHIMA?
A. In November the HIEI (BB) received a PT boat torpedo, damaged rudder and after completing circumnavigation of SAVO Island, was bombarded by an American destroyer or cruiser. A Japanese destroyer contributed to sinking the HIEI. Also she received damage from American destroyer and cruiser bombardment and by bombing from American planes. KIRISHIMA also sunk.
Q. Did the HIEI go on to GUADALCANAL to continue bombardment even though damaged?
A. Before she sank she was still shooting. The KIRISHIMA was sunk due west of SAVO Island. Due to no air support the cruiser YURA was also sunk about 25 October. It was near RABAUL, I think.
Q. Following the loss of the SOLOMONS Chain what were your new plans?
A. After the loss of the SOLOMON ISLANDS, the Americans were able to attack RABAUL with all types of planes. Because we had difficulty in supplying RABAUL, we took all the planes out of RABAUL to TRUK, about 21 February 1944. Following the first carrier Task Force attack upon TRUK, about 17 February 1944 by the Americans, the airplane losses were heavy; so we flew all but six planes to TRUK for reinforcements. Later about June or July, five or six planes at a time were flown from TRUK to KAVIENG and the ADMIRALTY ISLANDS. In August and September 1943 I was engaged in flight training near SINGAPORE, therefore I did not know what happened in the SOLOMONS at that time. I am not sure of any other plans but I think we were looking for some other area in which to make a defense.
Q. What happened to ground personnel at RABAUL and TRUK?
A. A good many had to stay. As many as possible were taken out by planes, flying boats and submarines to PALAU and DAVAO. A lot of them were killed by American bombing operations at RABAUL. Many aircraft maintenance personnel killed from that reason. Later operations were hampered because too many skilled personnel stuck at RABAUL unable to get out.
Q. What type of bombing do you consider the most effective?
A. B-24s were most effective on land bases. Because our fields were few, it was the size of bombs that did the harm. Little ones didn't do much harm. The number of crashes attempting to land on damaged fields was very great after B-24 raids. In a place like RABAUL where there were many fields, big bombs were not such a determining factor because we could land on an auxiliary field. Bombing effectiveness depends upon the target. The main thing that bothered us in operation was having several fields hit at the same time, leaving nothing to be used as auxiliary. Carrier planes on a small island with small targets or against ships were most dangerous. In an isolated place like TRUK with its many fields, carrier planes were most feared due to accuracy and repeated attacks. Whereas the heavy-bombers could only come one flight a day, carrier planes would keep coming all day for several days. Carrier planes always destroyed many of our planes and shipping which could not be easily replaced, whereas heavy-bombers mostly damaged airfields which were repairable. Also some supplies.
Q. Was the shipping in RABAUL Harbor damaged by bombing?
A. The big bombers did very little damage but the dive-bombers did whatever damage was done to the shipping. There were many ships sunk in the harbor by dive-bombers.
Q. Were we wise in attacking the RABAUL airfields?
A. Most distressing thing for us in a place like RABAUL was to have the shipping bombed. However, that depends on the target. The worst was attacking the shipping approaching RABAUL full of supplies.
Q. Were the American night bombing attacks effective on your shore bases?
A. The men became fatigued. Cut down fighting power. Didn't hit much.
Q. Were you present at any ports where American planes mined the harbors?
A. I was at RABAUL when that was done. At first they were not much of a nuisance and damage was minor. Later they were serious because they interfered with the supply submarines coming in.
Q. Do you know why submarines were used to supply instead of attack?
A. The use of submarines was not well done. Due to the loss of air control and shipping, the great length of supply lines committed our submarines to a policy of supply. The point is that there was no area fully consolidated enough to take care of itself. None of the points were self dependent. The use of submarines came from high authority, but I think the Army insisted upon their use.
Q. Do you know if airplanes were scouting for submarines which sank the WASP in September 1942?
A. I don't know much about that. I was on my way home, but plans were for that. In practice, communication between them was very bad.
Q. In early March 1943, our air forces pressed an attack on a large Japanese convoy in the BISMARK SEA. Do you know what losses the Japanese sustained?
A. It is being made upon FEAF report. If you will excuse me I would rather not talk about it until later.
Q. In the two battles of KULA Gulf, 6 and 13 July 1943, what were the losses?
A. Four destroyers were sunk, but I was at RABAUL. Didn't hear full details. The main thing that showed up for us was our bad radar.
Q. When was the radar first used on the airplanes?
A. First on planes at the beginning of 1943. After MIDWAY first on ships.
Q. When was the first on shore?
A. Little before July 1942. They were experimenting with it before the war.
Q. Did you have any plans to go back to BOUGAINVILLE after withdrawing?
A. No, We couldn't supply it.
Q. What were your duties in September-October 1945?
A. Came back to the Navy General Staff on 20 August last year, on action reports, current operations.
Q. What damage was thought inflicted on the United States Third Fleet off FORMOSA, on 14, 15 October?
A. Not very accurate reports. Most of the reports were from flight personnel who couldn't see very well. They said they thought they had caused damage to or sunk ten carriers. We thought back in the office that they probably had done serious damage to only four. Pilots report optimistically. We put that stuff in the paper. We thought in the office, and made plans accordingly, that the damage inflicted was less and that they had only seriously damaged four or five carriers.
Q. Did you feel that you had seriously affected American strength?
A. We took the pessimistic view when making plans, but made public the optimistic reports.
Q. Did you receive any information about American damage through radio despatches?
A. Yes. During operations, some of the ships we thought had been sunk began sending out radio, signals, so we knew they were not sunk.
Q. Was this done by traffic analysis, breakdown of code signs, or breakdown of the message?
A. We figured that certain very valuable ships have a particular wave length, and therefore we learned what the wave lengths were. When communicating with your own planes, we figured out what carrier it was.
Transcribed and formatted for HTML by Charles Hall, HyperWar Foundation