Interrogation of: Commander CHIHAYA, Masataka, IJN, who was attached to the Staff of Fourth Advanced Southern Fleet at AMBON from March 1944 to February 1945 and Staff of Combined Naval Fleet in TOKYO from February 1945 to September 1945. He was Anti-Aircraft Gunnery Officer while attached to the Staff of Combined Fleet.
Interrogated by: Captain Steadman Teller, USN.
The Fourth Advanced Fleet lacked adequate escort vessels to protect shipping in the NETHERLAND EAST INDIES - Western NEW GUINEA Area. Submarines and aircraft were approximately equal in damage inflicted. Aircraft attacks were largely responsible for stopping surface supply to the Japanese bases in Western NEW GUINEA. Night attacks by aircraft were very troublesome, daylight activities of our search aircraft took considerable toll of small craft.
The city of AMBON was completely destroyed by the Army B-24 raid on 25 August and adjacent airfields were made inoperative for about one month.
Q. What were your experiences with protection of shipping in the Southern Areas in 1944?
A. I was Operations Staff Officer, Fourth Advanced Southern Fleet Headquarters at AMBON. My concern was more with convoy escorting than with direct tactical operation. Until May 1944, the main transport operation had been supplying BIAK from MANILA. After the fall of BIAK, there were many ships, cargo and miscellaneous special jobs in the MOLUCCAS Area. After May, chief operation was supply from SOERABAJA to AMBON and ship traffic between MANILA and the HALMAHERA Area. From July on, removal of personnel from KAI Islands to AMBON and from BIAK and SANGA on the western extremity of NEW GUINEA to AMBON. There was a heavy attack on AMBON on the 25th of August. Vice Admiral YAMAGATA, Commander of the Fourth Advanced Southern Fleet Headquarters, was killed in an airplane crash near SHANGHAI on the way home in March 1945.
Q. What was the organization of your escort vessels?
A. Our escort vessels at AMBON consisted of one torpedo boat, the KIJI, and 15 converted trawlers of less than 500 tons and a maximum of 10 knots speed. No regular convoy routines were possible owing to the scarcity of escort vessels and their slowness. During the bad months of May and June 1944, my unit borrowed seven or eight small ships from SOERABAJA. At no time were any large naval ships, such as DD's or DE's, used for escorting in my area. The ships escorted were carrying provisions and personnel belonging to both the Army and the Navy. The escorting duty was the Navy responsibility. The only craft going without escort in my area were sailing boats; vessels of 1,000 tons and up received escorts. The area of escort responsibility for the Fourth Advanced Southern Fleet was between the eastern limit of 140ƒ East longitude and a line from PALAU to TALIABO Island in the NETHERLAND EAST INDIES and from that island a line running 160ƒ True.
Q. Were submarines used in your area for supply?
A. On the first of August of 1944, one submarine made one trip to BIAK; but she came under attack from a chaser north of BIAK before reaching BIAK and, without completing her mission, returned to AMBON. She was carrying food and medicine.
Q. What do you know of the loss of Japanese shipping in this area?
A. About three 2,000 tons ships were sunk by submarines near MANOKWARI, in the spring before the BIAK attack. In the end of May of the BIAK Campaign, six destroyers went up from AMBON to bombard BIAK and one of them was sunk by a skip-bomb up to the northeast of MANOKWARI. They did not complete their mission of the bombardment, nor did they have a full scale surface battle.
Q. Did they lose any ships in the surface battle?
A. There was no other serious damage.
Q. How far east were you escorting?
A. We went twice to WAKDE in May.
Q. When did you stop convoy into BIAK?
A. In the middle of May. That was the last surface group sent in to supply, and they received severe damage on that occasion from a group of B-24's bombing from 3000 meters.
Q. Which caused the most shipping losses in Western NEW GUINEA at that time -- submarines or aircraft?
A. If you take the total, submarines. In my whole area, up until May of 1944, the losses to submarines and aircraft were about equal; after May 1944, the air losses increased in proportion.
Q. How much interference with the shipping in the NEW GUINEA Area was caused by night attacks?
A. From early May through July 1944, the night attacks caused greater interference. I thought that it was PBY's doing it, operating from PORT DARWIN. Our ships had no radar, speed was low, lookouts were very unreliable and fear of submarines had made us take a special route, traveling by day and hiding by night. Beginning in May 1944, the principal damage you did was to bomb our hideouts so we could not take shelter. Our hideouts were at: MANLEA, BOEROE Island, bays on the north and south coasts of MANGOLE Island, the strait between MANDIOLI and BATJAN Islands and the north coast of MISOOL Island. We had been using a route along the south side of MANGOLE Island but when we thought that route was discovered, we took the route to the north side. When the SEIA MARU first went into North MANGOLE for the night, she was sunk, and when we finally got word in AMBON it troubled us as to what to do next. It was the first time this harbor on the north side of MANGOLE had been used.
Q. When the night attack on these harbors became severe, what did you do?
A. Changed all the night rendezvous and selected new routes along side of the island. We had no night intercepting planes.
Q. How long after that did it take our night planes to find you?
A. Harbors were only used two or three time before changing to another harbor; in fact, there wasn't a safe way of avoiding an attack.
Q. When did you stop convoy of shipping to West NEW GUINEA?
A. They stopped supply to MANOKWARI just before the BIAK action. At the end of June or first of July, we sent one ship into MACCLUER Gulf. That was the last supply. The KIJI (?) went alone in August to TONGERAI Cape (perhaps SANGARA) for evacuating this area. The Navy felt that the area had to be abandoned. The airfield at BABO was abandoned and personnel and some material were removed by this ship which made the last trip.
Q. During the period, approximately March to August of 1944, which air attacks caused most damage to shipping, the day air attack or the night air attacks?
A. It had been night attacks from May to August; after which, with operations commencing from your BIAK base, B-24 daylight attacks became the worse.
Q. When did you stop supplying the AMBON Area by surface ships?
A. By the end of July. The last ship to go into it was ITSUKUSHIMA MARU. On the 30th of July she set mines in the entrance of the Gulf and withdrew to LEMBE, east of MENADO, where she received serious damage from one group of about nine B-25's which attacked her in port. She remained hidden, repairing at LEMBE, for one week and then started down to the JAVA SEA under tow, where she was sunk by a submarine approximately 6ƒS and 115ƒE.
Q. Were you forced by the threat of air attack to stop supplying the HALMAHERA Area or by shortage of ships?
A. We had stopped sending supplies in there because the troops that had been intended to go over to the NEW GUINEA Area from HALMAHERA could not make it; so we already had extra supplies at HALMAHERA.
Q. When did you stop convoying in your area to all intents and purposes?
A. Middle of October 1944, a 1,000 ton ship came over from SOERABAJA to AMBON. She made port safely; but on the return journey, she was sunk by three B-25's in position 5ƒS, 126ƒE. That was the last ship that came into AMBON. She had left port the evening before. At about 1000 the following day, was sighted by a B-24 (the daily four-engine search planes came over AMBON about 1000 or 1100 each day) and the attack occurred about 1700 that day. This attack consisted of strafing by two of the B-25's which silenced the AA batteries and immediately following, the third B-25 bombed from low level and sank her.
Q. To what extent did the single search planes, which covered your area daily, damage the shipping.
A. Many small craft and auxiliary ships were sunk by search planes, but not any big ships with names.
Q. Were your large ships equipped with many guns?
A. Up to June 1944 a 1,000 ton supply ship would have four 25mm. machine guns; after June she would have about ten.
Q. After you stopped sending large ships in your area, did you use small ships to supply or evacuate from those islands?
A. We used small craft for supply to October 1944; after October 1944 it was completely stopped. Once a month, beginning December, a plane would come from SOERABAJA; then after the LUZON occupation by U.S. Forces, the number of planes was increased to three or four per month from SOERABAJA. In February 1945, I received orders and left AMBON by plane, proceeding to TOKYO via SOERABAJA. Admiral YAMAGATA and half of his naval staff left AMBON in March. The remainder of his staff remained there until the end of the war. In April 1945, a number of ships evacuated some of the Army and Navy from AMBON and islands in the vicinity.
Q. What type of naval AA weapons were being given the greatest emphasis in the beginning of 1945?
A. The most emphasis was placed on the 25mm. machine guns, next on the 12cm. high angle guns. This emphasis was placed on both production of guns and on installation on all types of naval vessels.
Q. Did you personally experience any air attacks at AMBON?
A. Yes, on the 25th of August 1944, about 50 B-24's attacked AMBON and almost completely destroyed the city, but not our headquarters or the harbor installations and ships. There were three attacks on AMBON by B-25's and B-24's mixed. The heaviest was an attack at the end of August by 100 to 120 planes which lasted all day, rendering the fields unserviceable for about a month and destroying buildings and facilities on the airfields. There was no damage to light material which could be hidden in safety tunnels. There were almost daily attacks during September amounting to a total of about 150 planes. At the end of October after the LEYTE Campaign had begun, the airfields were under frequent attacks, but we mended there quickly and what we could not mend we made look as if they were mended in order to draw the attack from LEYTE. We also had dummy planes installed. After August there were few attacks on the harbor and that perhaps was because we had installed a great many machine guns on the ships and shore. The city of AMBON was completely destroyed.
Q. Did those dummy planes draw the attacks of our planes?
Q. How successful were your AA in shooting down our planes at AMBON?
A. Those of which I have sure knowledge on raids were: crashing on land -- two P-38's, crew killed; two B-25s, crew killed. On the water, one B-25, crew saved by PBY from rubber boat; one P-38, crew saved.
Q. How many heavy AA guns did you have at AMBON?
A. 28 heavy AA guns at AMBON; 14x12cm. high angle guns and 14x8cm. high angle guns.
Q. During 1945 was the Navy able to obtain all the AA ammunition that was needed for the many new guns being built?
A. It was extremely short in JAPAN, but the fleet received all it needed.
Q. What do you consider the best type of ammunition to use in AA machine guns?
A. I considered the best ammunition loading to be three high explosive to two incendiaries; however, due to the shortage of incendiary, we were forced to use four to one.
Q. What was the size of the main battery guns on the battleship YAMATO?
A. 45 cm. and 45 caliber. Initial velocity less than 800 meters per second. Range 38,000 meters.
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