(Document reprinted as received from Alan Matthews)

COPY Australian War Memorial (AWM) 423/6/30
(Extract from files of G-2 W.D. Intelligence, S.C.A.P.)
                                    (NAV NO 77)                       DATE: 14 November 1945
          Time: 1330 – 1700
Division of origin:       Naval Analysis Division
Subject:                        22nd Air Flotilla Operations on Malaya
Personnel interrogated and background of each:
Captain Sonokawa, Kameo, IJN was Flight Leader of Genzan Air Corps, in Genzan Korea from 1 September, 1941 to 1 April, 1942: Flight Leader of Takao Air Corps in Takao, Formosa from 1 April, 1942 to 1 February, 1943; Staff of Naval Air Headquarters Tokyo from 1 February, 1943 to 1 August, 1944; Staff of 23rd Air Flotilla, Kendari from 1 August, 1944 to 20 February, 1945; Attached to the Yokosuka Naval Station in Yokosuka from 20 February, 1945 to 15 April, 1945; Commander of 210 Air Corps in Nagoya from 15 April, 1945 to 3 August, 1945; Staff of 32nd Air Flotilla on Oita from 3 August, 1945 to 30 September 1945. 
Where interviewed;                           Meiji Building Room 238
Interrogator;                                       Commander T.H. Moorer, USN
Interpreter;                                         Lieutenant Commander S, Millstein, USNR
Allied officers present;                      None.
This interrogation is concerned with the operations of the Japanese naval land-based aircraft during the occupation of British MALAYA. Captain SONOKAWA was commanding officer of the Genzan Air Group and has furnished a detailed and interesting account of the sinking of HMS REPULSE and HMS PRINCE OF WALES.
Q- What naval air forces were based in SAIGON area at the beginning of the war?
A-    There were three units comprising the 22nd Air Flotilla:
Genzan        36 BETTYS         12 in reserve
Mihoro      -      36 BETTYS         12 in reserve
Kanoya      -      27 BETTYS           9 in reserve
Also attached directly to the 22nd Air Flotilla were 18 fighter planes, six in reserve, six reconnaissance planes, Genzan was situated at Saigon, Mihoro located about 20 miles north of Saigon, Kanoya Force established about 60 miles southwest of Saigon.
Q- During the invasion of the PHILIPPINES and the NETHERLAND EAST
INDIES what was the mission of the 22nd Air Flotilla based in SAIGON?
A-    We had no participation in the PHILIPPINES Operations. We acted in direct support of the MALAYAN invasion and gave slight support in the BORNEO and JAVA Operations. For operations in the PHILIPPINES and NETHERLAND EAST INDIES, the 11th Air Fleet less than the 22nd Air Flotilla was responsible. The GENZAN Air Group which I commanded later became the 775th Air Squadron.
Q- Was the GENZAN Air Group controlled by the 11th Air Fleet?
A-     Yes, all naval air forces at SAIGON were under the 11th Air Fleet at TAKAO.
Q- What was the state of training of GENZAN Air Group?
A-    It was the best unit in the 11th Air Fleet, which was manned with very experienced and competent pilots.
Q- What type of attack did you specialise in?
A-    Bombing and torpedo attacks against ships; also night operations.
Q-Was special torpedo attack training given?
A-    Yes, each pilot was trained with live torpedoes.
Q- Explain the basic torpedo tactics used by you.
A-    Although the ordnance department claimed that the torpedoes could be dropped at an altitude of 500-metres, we found by experience that only 10 per cent would run properly at 200 meters and 50 per cent at 100 meters. Consequently, an effort was made to drop at from 20-30 meters. Since the aircraft torpedo was dropped at short range the low altitude afforded protection because of depressing limit of AA guns. Pilots were instructed to attempt to drop the torpedo in such a manner that it struck the ship immediately after it levelled off at set depth. Of course conditions varied but a standard drop was made from a range of 600 to 400 meters, at a speed of 160-170 knots and at altitude of from 20 to 50 meters. The aircraft torpedo was armed immediately after striking the water. It weighed 800 Kg and had a 145 Kg warhead. The above tactics were used by our carrier planes against your LEXINGTON. After the battle of the CORAL SEA the size of the warhead was increased to 220Kg.
NOTE:-The interview now moves directly onto issues surrounding the sinking of HMS Repulse & HMS Prince of Wales.
Q-How were the two ships located?
A-    We had previous intelligence reports that the British battleships were probably in the area but did not know for sure. On 8 December the ships were photographed in SINGAPORE Harbor. There were no air searches on 9 December because of bad weather. However, on afternoon of 9 December the ships were sighted by a submarine which gave their position (approximately 7 degrees North – 105 degrees East, course 000 degrees).
Q- Upon learning of the position of the two ships, what action was taken?
A-     We received the first sighting report from a submarine at 1600, 9 December. The message was originated at 1400 but not received at the 22nd Air Flotilla Headquarters until two hours later. At that time we were in the process of loading bombs for an attack on SINGAPORE Harbor. We re-armed with torpedoes as quickly as possible. This was not finished until 1800 and although it was getting dark we decided that in spite of difficulties we would attempt a night torpedo attack because it was feared that the REPULSE and PRINCE OF WALES would attack our invasion transports. In order to cooperate with the aircraft and sink any damaged enemy ships, the HARUNA and KONGO were also ordered to make contact if possible. Due to bad weather the aircraft were unable to locate the enemy ships and returned without mishap about midnight. At 0315, 10 December a contact report was received from a second submarine which gave a new position indicating that the ships were heading South and returning to SINGAPORE. At 0600, 10 planes (GENZAN 260 kg bombs) were launched to conduct a sector search for enemy ships. About one hour later the striking force, composed of 88 aircraft (27 bombers – 61 torpedo planes) was ordered to proceed to the best estimated position of the enemy ships. The striking group was organised into 9 plane flights which proceeded south along the 105th meridian, as soon as they rendezvoused. Because of reduced visibility the search planes did not discover the enemy ships until after beginning the return leg. At 1100 hrs the contact was broadcast to the striking group and headquarters.
Q- Describe the method of attack. Who controlled the attack?
A-     The attacks were controlled by the flight leaders and were ordered according to the situation. The general plan was to attack continuously, leading off with a bombing attack from 2500 meters by the GENZAN Group. They were followed in turn by the MIHORO and KANOYA Groups as soon as they arrived. The first attack began at 1130.
Q- Approximately how many planes attacked each ship?
A-    The planes divided their attack approximately as shown below:
PRINCE OF WALES                                   REPULSE                               
   Bombers             T/Bombers                Bombers         T/Bombers                    TOTAL
GROUP        9                           9                      0                      9                           27
GROUP       9                            9                      9                      8                           35
GROUP      0                             6                                              20                          26
TOTAL       18                            24                     9                      32                           88
Q-Why were more torpedoes directed at REPULSE than the PRINCE OF WALES?
A-    The first attack by the GENZAN planes was successful in slowing the REPULSE to such an extent that the pilots were attracted to the crippled target. It was originally planned to concentrate on the PRINCE OF WALES. (Note :- I find this part of the interview somewhat questionable; reason being Prince of Wales was crippled after the first torpedo attack. She was hit in the stern, twisting a propeller shaft. In turn, the seals of the shaft failed, and the ship eventually took on more than 18000 tons of water and most of the main electrical systems failed.  Consequently, I believe that Captain Sonokawa may have recalled this phase of the battle incorrectly. As I am of the opinion, because the initial torpedo attack effectively crippled Prince of Wales, the main strength of the Japanese air attacks were directed against Repulse. In support of this theory, we must remember that Captain Tennant of Repulse evaded more than 19 torpedo’s before his ship finally succumbed. During which time, Repulse was manoeuvring sometimes at speeds in excess of 25 knots.    
Q-Estimate the number of hits received by the British ships.
A-    The REPULSE was hit by one or two bombs and about 12 torpedoes. The PRINCE OF WALES  was hit by one bomb and 10 torpedoes. I am not sure about the bomb hits.
Q-How many aircraft were lost?
A-    A total of 4 aircraft were lost during the attacks, one by the GENZAN Unit and three by the KANOYA Unit. I think their loss was caused by the high altitude they used to drop the torpedoes. Since they were the last to attack their losses should have been less.
Q- Did all planes of the striking group take part in the attack?
A-    No, a few bombers became separated and attacked a British minelayer, also one bomber formation made a premature drop. The leader dropped by mistake and everyone followed suit. (Note:- The ship that was attacked, I believe to have been the destroyer HMS Tenedos. This had left Force ‘Z’ the evening before to steam for Singapore, because of fuel shortage. No hits were scored on the destroyer).
Q-What were the weather conditions, at the time of the attack?
A-Weather was clear over ships; some cumulus at 500 meters.
Q- At what time did the British ships sink?
A-REPULSE sank 1230, PRINCE OF WALES about 30 mins later.
Q-What was the location of the sinking?
A-    The scene of action was about 50miles east of Kwantan {sic}  airfield (4 degrees N – 104 degrees East). I think the ships were separated about 5 miles when they sank.
Q-What happened after the attack?
A-After the attack one plane was left to observe results. He remained on  
    station until both ships sank. During this time ten BUFFALO fighters arrived
    but the observing plane managed to escape. Japanese fighters arrived too
    late to take part in the action. Six or seven bombers were reloaded for the
    second attack but before they could take off they were sunk.
Q- What was the general operating condition in the SAIGON area so far as airfields, technicians, etc were concerned?
A-    Supplies of fuel, parts, etc were very good during MALAYAN Operation; also the maintenance was excellent. Furthermore, the type of pilot we had was high standard and during the whole MALAYAN Campaign my unit lost only two planes, one at PRINCE OF WALES and REPULSE battle and one at SINGAPORE. We always had full strength of 36 planes.
Q-What was the gist of the operation order for the MALAYAN Campaign so far as aircraft were concerned?
A- There was two missions: one was offensive, to support operations in MALAYA, BRITISH BORNEO, and JAVA SEA; second was reconnaissance of the South CHINA SEA. We did not support land operations in MALAYA because that was an ARMY job but we were ordered to attack the British Fleet at Singapore.  
Q- What ARMY air forces were available in SAIGON Area to support the MALAYAN Campaign?
A-    About 200 planes.
Q- What Mission was assigned to ARMY planes?
A-    Direct cooperation with the MALAY Landing, the NAVY didn’t cooperate directly at all.
Q- Did your group take part in the attack on REPULSE and PRINCE of WALES?
A-    Yes, all available Navy planes were used in the attack.
Q- What effect did this tremendous success have on your future planning?
A- One result was the adoption of my conception that torpedo bombing at 20 meters was more efficient. Second result was the emergence of the conception that the airplane was more powerful than the ship. We had a conception that the aerial torpedo was very effective and so we increased training. Also the morale of the air personnel was raised very much. However, the Japanese still did not fully appreciate air power. Failure to recognise value of air power was one of our greatest causes of defeat.
Q-What missions did the 22nd Air Flotilla at SAIGON perform in the occupation of British BORNEO?
A-    While our basic directive was to support and participate in North BORNEO Operations, the landings and operations there were so simple that there was nothing for us to do; so actually we didn’t do a thing.
Q- After the MALAYAN force moved from SINGAPORE down to BATAVIA, did the 22nd Air Flotilla participate in anyway in the JAVA and SUMATRA Occupations?
A-    We had nothing to do with the SUMATRA Operation but cooperated in the JAVA Operation in two ways. One was escort of convoys to the landing point west of BATAVIA. Second way was to attack combined naval units coming out of BATAVIA to resist the landing forces.
Q- In the meantime, did you search and escort work in the south-west area during December, January and February?
A-    Until middle of January 1942 we patrolled South CHINA SEA; after that time we patrolled JAVA SEA.
Q- How far eastward did you patrol the JAVA SEA?
A-    Patrolled the western part of JAVA SEA to center of JAVA.
Q- What were your total losses in aircraft in these three squadrons up until they captured JAVA?
A-    Altogether GENZAN lost two, MIHORO one, KANOYA three.
Q- Did you make any attacks on American submarines in this area?
A-    Never sighted any.
NOTE: The remaining part of this interrogation covers operations during the Allied moves towards the PHILIPPINES.
Q- On 1 August 1944 what forces were assigned to the 23rd Air Flotilla?
A-    After August 1944 the 23rd was a maintenance unit with no planes.
Q- From 1 August 1944 until February 1945 did the 23rd Air Flotilla continue to act as a maintenance unit?
A-    Yes, until February 1945 our function was merely maintenance and defence. Defence was carried out by anti-aircraft guns not by planes. However, the ARMY had heavy bombers based at KENDARI for attacks on MOROTAI.
Q- What bases were under your command?
A-    We had only KENDARI and AMBESIA (15 miles south of KENDARI).
Q- Who maintained the other bases in the CELEBES Area?
A-    13th Air Fleet.
Q-Were the aircraft operating from these bases ARMY or NAVY?
Q- Were there any naval land-based aircraft in the CELEBES-BORNEO Area after 1 August 1944?
A-    No, these were the only bases used and they were for maintenance. At BAILIKPAPAN the 13th Air Fleet had fighters for defensive work. 13th Air Fleet Headquarters were at SINGAPORE.
Q-What other forces were controlled by 13th Air Fleet?
A-    BALIKPAPEN – 381st Squadron, 70 fighters; SINGAPORE – 331st Squadron, 10 fighters plus about 20 carrier type bombers. About 90 training planes were scattered through SINGAPORE and Java Area.
Q-Was the mission of these planes at SINGAPORE and BALIKPAPEN purely defense?
A-    I know for certain the planes used at BALIKPAPEN were for defense. The mission of the planes of the 13th Air Force is not certain.
Q-Did the Navy at that time (Fall 1944) abandon bases around JAVA SEA Area?
A-    13th Airforce was using them, bet we were in the process of abandoning the fields and were getting rid of all the planes which were operational and could fly away.
Q-What aircraft in the BORNEO - CELEBES  Area were responsible for the defence of MOROTAI, BRUNEI Bay, TARAKAN Area?
A-    The Army. The Navy maintained certain bases. The 7th Air Army was responsible for the defence of MOROTAI. No Navy planes were available, only defense personnel on the spot.
Q- Did any of the 11th Air Fleet or the 22nd Air Flotilla have any previous combat experiences in CHINA?
A-    The whole 11th Air Force in its entirety participated in ait attacks on CHINA, based at HANKOW and attacked CHUNGKING. This was July and August 1941 before basing at FORMOSA.
At this juncture the interrogation quickly curtails on the following note:
When furnishing details concerning the PRINCE OF WALES and REPULSE action, Captain SONOKAWA was assisted by Commander SHIGEMURE, intelligence officer of the 22nd Air Flotilla.