The following data concerning speeds and ranges are based both on what POW had experienced and on what he had read. His experience was not great and the information should be evaluated accordingly.
At economical speed of about 130 knots IAS at 200 meter altitude carrying torpedo, about 900-1,000 miles. This was based on 1,550 liter fuel load, war condition, using 87 octane gas, figuring a fuel consumption of about 180 liters per hour. It vas POW's opinion that figures given in JAPANESE AIRCRAFT, Performance and Characteristics, TAIC Manual No. 1 were too high. Figures on which POW based his opinion are all his estimates.
POW was informed at KUSHIRA that allowing tine for run-in, launching, evasive tactics, etc. in the battle area, the distance from KUSHIRA airfield to southern OKINAWA would leave little gas in the tanks on his return. This flight was to be made with 87 octane gas, war condition (torpedo), speed (IAS) en route about 125-130 knots, altitude about 150 meters.
Range in Recce Condition
Estimated about 1,600 miles at economical speed, 87 octane, but POW was unable to recall clearly.
At about 5,000 meters, maximum speed level flight without torpedo using 87 octane gas and cutting the supercharger and water-methanol, about 260 knots. POW said his fastest level flight at 1,000 meters in recce codnition with 87 octane gas cutting in supercharger and water methanol was about 230 knots by his instruments. He said, however, that he held this speed only an instant, but thought that he could have run it up to about 250 knots had he continued to gun the plane.
With torpedo war-load and 87 octane gas, level flight, maximum speed cutting in supercharger and water-methanol was estimated at about 200 knots IAS, altitude unverifiable. POW observed that in his opinion TAIC figures in above mentioned manual were too high.
POW's plane was new; it had about 60 hours flying time when he took it into action.
About 9,000 meters, recce condition, 87 octane.
Top gun (flexible) 1 x 7.9 mm; bottom gun (flexible) 1 x 7.9 mm; no forward firing guns. Fields of fire about 180° for each gun. Elevation from horizontal about 90° for top gun and about 60° for bottom gun. About 3,600 rounds carried.
Steel plate about 50 cm wide, 60 cm long, 1.5 cm thick between engine and cockpit ahead of oil tank in position shown in POW's sketch below:
POW said that formerly JILL 12 fuel tanks were lined with about 5 cm of fairly effective protective rubber lining, but that because this reduced fuel load and range, new planes lack this protection. He observed that the pilots did not like it, preferring fuel to safety, and often got the lined tanks changed.
Estimated that about half of JILL 12 are equipped. Lead plane, at least, likely to carry it. None on P0W's plane and details unknown. POW's sketches, however, based on observation of gear on other JILL 12 indicated YAGI antenna carried_ on the leading edge of port wing about 1/3 of the distance in from wing-tip and similar antenna on either side of the fuselage aft of the cockpit. Length of antenna on wing about one meter with dipoles equidistant apart. Projected forward. Fuselage antenna had dipoles projecting from fuselage at roughly right angles center-pole running roughly parallel to fuselage lines. POW said this was search radar to pick up ships and planes.
Three oxygen bottles, each somewhat less than one motor high and about 10 cm in diameter, carried on the right side of the center seat. POW did not believe there was any oxygen-producing equipment carried.
About 1,550 liters maximum fuel load. No jettisonable tanks. 87 octane gas. No removable.
One torpedo (modification 7, type and model unknown) 800 kg or 1 x #80 800 kg bomb or 6 x #6 60 kg bombs. POW thought only one 250 kg bomb could be carried because of kind of bomb-carrying gear. He had had no experience, however. Water-methanol - 68 liters carried. Partial cut in up to five minutes continuous is allowable; 30-second continuous full cut in for absolute maximum speed is allowable. Tank located between oil tank and cockpit. ADI comes on automatically at 150 mm manifold pressure if pilot has previously engaged lever which sets automatic injection on.
Modification 7 (KAI NANA) Aerial Torpedo
Typo, model, and technical details unknown. Speed 42 knots; fuel: alcohol, compressed air, fresh water system. One small flexible stabilizer (ANZENBAN) about 10 cm square on each side to prevent roll. Torpedo is armed by a small vein topside of warhead. POW called this the "safety-pin" (ANZENSEN). While pin is perpendicular to torpedo surface, torpedo is on safety. When the torpedo enters the water, pressure of motion forward bends pin back parallel to torpedo surface. The missile then explode upon impact, probably, POW thought, on inertia principle. One gyroscope.
Torpedo carried below fuselage with two guide clasps and one holding clasp (see POW's sketch below). A small can of explosive is carried at point B at the holding clasp joint. The pilot detonates this at release point by electric switch; the joint is forced apart and the torpedo drops. Rough sketch (not to scale) is drawn on next page.
Modification 7 can be dropped from 150 meters, but standard is 50 meters altitude.
Landing Guide Lights (CHAKURIKU SHIDO TO)
These lights arc supposed to help the pilot avoid coming in too high or too low and overshooting or undershooting the runway at night. A frame containing about three blue lights is set flash on the ground close to the runway facing the direction of approach. About 5 meters diagonally ahead and closer to the runway a similar frame or red lights mounted on a stand about 70 cm high is set. These lights are set in such a position that if the pilot comes in too high, the blue lights appear to be above the red relative to his line and plane of descent. Conversely, if his approach is too low the red lights appear above the blue relative to his approach line. If he is coming in at the correct altitude and approach angle of descent, the red and blue lights appear to line up in one row. POW's sketch follows:
9. TRAINING AND OPERATIONS
Nearly four months. Subjects studied included arithmetic, physics, communications (flag and radio Morse), navigation, military affairs, maintenance (KOTOBUKI model (KATA) 2), physical drill, cutter operation. Course very easy for POW after his education. Knew only of two failures.
Elementary Flight Training
Type 93 training plane. Total flying hours in this stage of training about 65 from 25 Jan 1944 to 30 April 1944. Flying hours included the following (all approximate):
Solo: about 10 flights totalling about five hours after about four and one-half flying hours.
Formation flying with instructor. Formation of three planes. About 15 hours and about 15 flights.
Aerobatics (SUTANTO from English stunt) including spins, loops, Immelman turns. About 25 hours with instructor; about 25 flights.
Instrument flying: about four hours, but not in bad weather and always with instructor.
Military formation flying: six planes, 12 hours, very few flights, with instructor.
Ground training at this stage included radio (Morse), about 100 hours maintenance Type 93 trainer, about 60 hours aerial navigation, about 20 hours of pilot ground training including Link Trainer.
Combat Plane Training
Type 97 KATE. Total flying hours about 60 at this stage, from 30 April 1944 to 28 Aug 1944 at TAINAN. Flight training included about one hour solo (two flights), about 40 hours flying with instructor (DOJO HIKO KUNREN), and about 20 hours flying with other trainees (GOJO HIKO) trading off on controls. Team rides included about seven hours of blind flying, but never in bad weather. POW also had about three hours of blind flying with instructor. Blind flying included level flight, glide, and climb at fixed speeds, but POW had no training in blind landings or take-offs. It also included standard rate and double rate turns. POW observed that under then current and present conditions, there is no time for training in blind landings and take-offs at this stage.
Flight hours also included formation flying (3 planes) and, on about two occasions, multiple formation. Single-plane dummy runs against land targets (stationary) and formation runs against fishing boats were practiced. No dummy torpedoes were dropped, however.
Ground training at TAINAN was practically a review of training received at TAKAO, but with very little communications. It included Link Trainer, using a model of KATE. There was some study of KATE's engine, but POW could not recall any details.
TACTICS AND MISCELLANEOUS
POW was taught that standard run-in altitude is 50 meters, as is torpedo release altitude. Release distance is 1,000 meters. In his only actual attack (sec Sec 3) POW came in at proper altitude, but released his torpedo at about 1,500 meters because of heavy AA fire and a "mistake as to distance." Standard evasive maneuver is to swing from side to side with little change in altitude. Where approach is over water, run-in usually commences at about 10,000 meters from target, though this may vary according to circumstances. Speed 180-200 knots IAS - full speed with ADI.
No fixed altitude. In his only mission, however, POW's approach altitude was 150 meters. POW ascribed this first to the fact that in a night attack the low altitude enabled the navigator to see the sea surface to check wind direction and secondly to avoidance of radar detection. Approach speed about 125 knots IAS in POW's attack.
Formation breaks at about 10,000 meters from target and two after planes swing around to hit opposite side. Approach begins at about 50,000 [5,000?] meters from target, 200 meter altitude, take distance about 200 meters, take height about 50 meters, speed cruising (120-130 knots). Run-in from about 10,000 meters distance, column formation on both sides of target, 50 meters altitude, each element of two planes one side simultaneously. Other run-in data as explained under Run-In above. POW had practiced this attack against a DD about five times at KATORI, using Modification 3 torpedo (type and model unknown) with charge removed.
Envelopment Attack (HOI KOGEKI)
POW had done this in practice once at USA. He sketched and described it as follows:
The eight-plane multiple formation splits at at least 20,000 meters from the target, at altitude of about 3,000 meters. Aft formation of four planes swings around to opposite side of target as shown. All planes take approach altitude of about 200 meters from break-up of multiple formation. From 10,000 meters from target or as soon as enemy sighted, the four planes in each group deploy as shown and begin run-in. Run-in interval, wing-tip to wing-tip, was about 500 meters. Other run-in data as previously set out. Attack is simultaneous from each side.
In the event that time or circumstances do not permit this type of envelopment, one formation of four planes swings right, the other left, so that on run-in envelopment is as follows on next page:
"Wheel formation" (KURUMA GAKARI). POW had never tried this, but had learned it only from models while at USA. He described and sketched it as follows:
Radius of circle (from target) approximately 8,000 meters. Altitude of planes at circumference about 1,000 meters. Speed of planes at circumference about 120-130 knots. Run-in data from circumference as previously described. Planes were to attack as opportunity offered, according to the judgement of the individual pilots. The maneuver may be either counter-clockwise (HIDARI MAWARU) or clockwise (MIGI MAWARU).
Two-plane night attack: POW had practised this attack three tines at KATORI. Target illuminated by planes from recce plane. Approach at 200 meters altitude (oversea), formation thus . Run-in from 10,000 meters from target, column-formation, speed full, altitude 50 meters, release distance 1,000 meters. Column formation from commencement of run-in. Flares are dropped in night torpedo attacks at order cf lead attacking plane to recce plane or planes.
Window A metal-coated paper package released by hand and unrolled by string catch, releasing 100 or more sheets about 5 cm wide and one foot long. Plane carried about six packages. One to be dropped at a time. Dropped in case of US night fighter attack or on attack against ship target. Immediately after dropping, course changed.
Target Priorities In case of a carrier Task Force, target importance for torpedo-plane attack CV, BB, CA, CL, DD in that order. POW was ordered to give first priority to transports, then warships in order as above. He received no description of AGC or order to attack it first, but said that he would attack such a ship first if he knew of it. If en route to Okinawa had encountered a target, he would have radioed its position, but would have continued his mission unless the target were a carrier and its planes prevented his going on. In that case he would have attacked the carrier.
Suicide Pilots No experience or training as such. While POW was at USA in late 1944 a volunteer notice (GANSHO) was received asking instructors to volunteer for this duty. Not all the instructors did so, but most, including POW, did. Nothing came of it in POW's case, but he expected that he would have become a fighter pilot had he become a suicide man. He thought that mostly very young men of little experience became suicide pilots. While POW was with the K-256th HIKOTAI at KATORI in early 1945, the outfit had a chance to volunteer as a suicide unit. The HIKOTAI CO, however, turned down the opportunity. POW noted that not everybody is in sympathy with throwing away pilots and planes. Had the CO decided to accept, however, all the unit would have followed him perforce.
12. ENEMY SUPPLIES AND INDUSTRY
POW understood that USA flying hours had been about 80 for combat-plane trainees until about March 1944. Gradually, they have been cut down at USA and presumably elsewhere to about 60 hours owing to gasoline shortage.
POW was not aware of any lack of plane spare parts, at least for ordinary maintenance requirements. He understood from maintenance people, however, that quality was not up to earlier standards frequently, but know no details.
15. WASTAGE AND CASUALTIES
Operational Failures JILL 12
Out of the some 35 JILL 12 in POW's outfit at KATORI about four per day on the average were non-operational as a result of dirty spark plugs, a condition in turn caused, POW thought, by some defect in the carburetor.
Four JILL 12 were lost in training of K-256th HIKOTAI at KATORI. One of these was destroyed when during a training run-in with AA avoidance tactics the rudder broke under the strain of weaving from side to side. Causes of other crashes not known, but POW heard that somehow dew from the wings might have gotten into the gas, probably from the dew which he said formed easily around the mouth of the gas in-put pipe.
---The information herein has been obtained from Prisoner of War sources and must be judged accordingly---
Today's post is a follow-up of the excellent "Jill" photos of the 131Ku. It's an interrogation report of a Japanese POW, a "Jill" pilot of the 131Ku that gives a lot of interesting information about the unit but also technical details of the aircraft, the methods used for torpedo attacks and the training of the pilots. The POW was captured on April 1, 1945 off Okinawa and we chose not to include his name or other personal information.
Information in this detailed report is confined principally to three subjects: Naval Air Order of Battle, air training, and the performance of JILL 12.
POW was a pilot attached to K-256th Flying Unit (HIKOTAI), 131st Air Group (KOKUTAI). His information on the history, strength, personnel, and organization of this outfit, as well as of other Units and Air Groups, is detailed and, as far as it could be checked from other sources, accurate.
The various stages of POW's training as a pilot are considered here at some length. Certain grave deficiencies are apparent. His instruction lacked diversity, he had very few flying hours according to our standards, he had no knowledge whatever of radio navigation aids (he depended entirely on his navigator for navigation and instrument orientation), and his training in instrument flying and night flying was cursory at best.
Finally, POW gave considerable information on the performance of JILL 12. It was his opinion that performance figures in TAIC MANUAL NUMBER 1, JAPANESE AIRCRAFT, PERFORMANCE AND CHARACTERISTICS, are generally too high.
Aug - Volunteered as reserve flying cadet at TOKYO.
13 Sept - Entered MIE Air Group for pre-flight training.
4 Jan - Transferred with 400 other cadets to TAKAO Air Group.
10-11 Jan - Boarded CHOHAKUSAN MARU and left MOJI in convoy of about nine vessels including two DDs. One SS contact en route, but convoy not attacked. POW heard SS was depth-charged without observed results.
17 Jan - Arrived TAKAO; reported to OKAYAMA (TAKAO) Airfield and entered TAKAO Air Group. Took elementary flight training in Type 93 training plane.
30 April (approx) - Completed elementary flight training and transferred to TAINAN Air Group with about 400 cadets from TAKAO. Took combat-plane training in Type 97 TB KATE.
30 June - Commissioned Ensign.
28 Aug - Transferred to USA Air Group as flight instructor in KATE.
Late Dec - Transferred to K-256th Flying Unit (HIKOTAI), a JILL 12 outfit in the 131st Air Group at KATORI Airfield.
29 March - Left KATORI with about 20 JILL 12 from K-256th HIKOTAI, arriving KUSHIRA Airfield, KYUSHU.
31 March - Left KUSHIRA Airfield on his first war mission at about 2230 ITEM in JILL 12 on torpedo attack mission against US trapsports off OKINAWA. About 25 JILL 12 were to participate, but all were to proceed and attack independently. Planes left from 2100 on.
1 April - Reached US transport area about 0130, launched torpedo at transport without observed results. Crashed. Captured.
3. DETAILS OF CAPTURE
When POW launched his torpedo, he was at an altitude of about 50 meters (164 ft). Flying low, he turned right to avoid one or more US night-fighters, possibly P-61, coming in from his left. As he came out of the turn, still very low, he kept his eyes on the US planes. This moment of inattention to his altitude apparently caused the crash. The radioman was lost, but the plane captain-navigator and POW were rescued by a US DD.
POW was not on a suicide mission.
131st Air Group
POW joined the K-256th Flying Unit (HIKOTAI) of this Air Group at the and of Dec 1944 or early Jan 1945 at KATORI Airfield, remaining at this field until 29 March 1945. The Air Group was composed of the following units:
A JILL 12 outfit. The HIKOTAI flight personnel were made up of about 60 pilots, 60 navigator-bombardiers, and 60 radio operators. As of the end of March 1945, the plane complement was about 35 JILL 12, scheduled complement about 50 JILL 12. This included at most five reserve planes, with a scheduled reserve of about 10. Maintenance personnel complement was about 100.
The outfit was organized at KATORI in early Jan 1945 with new planes. Officer flight personnel, about 25, had for the most part been instructors after finishing combat-plane training. Including POW, three officer pilots, former instructors, had come from USA. Most of the flight personnel had come straight from training Air Groups (combat-plane training).
The unit was scheduled to move to KUSHIRA Airfield, KYUSHU, at the end of March 1945, but by 31 March only about 20 planes had arrived there. Maintenance personnel had not been sent at this date, but POW thought they would probably be sent to KUSHIRA. The CO of the 131st Air Group also moved to KUSHIRA with the K-256th HIKOTAI. His staff did not come; he went merely to look after the HIKOTAI.
Combat organization was five Divs (CHUTAI) of two Secs (SHOTAI) each, four planes per SHOTAI. A KUTAI consisted of two planes; there were two KUTAI per SHOTAI.
A radial-engince JUDY outfit formed at KATORI at the same time as K-256th HIKOTAI. Plane strength aggregated about 50 but included about five GRACE. Flight personnel numbered about 60 pilots and the same number of crewmen. The number of maintenance personnel was unknown. As of 29 March the unit was still undergoing training at KATORI.
Unidentified Fighter HIKOTAI
Scheduled to join 131st Air Group at KATORI, but had not arrived by 29 March.
About two attached to 131st Air Group; separate from HIKOTAI maintenance outfits.
5. IDENTIFICATION OF OTHER UNITS
MIE Air Group
POW entered this Air Group 13 Sept 1943 for pre-flight training as a reserve cadet (YOBIGAKUSEI); he remained in the Air Group until 4 Jan 1944. Student personnel numbered about 2,500 reserve cadets who entered with POW in 12 BUNTAI and about 2,000 enlisted trainees (RENSHUSEI). There were about 1,000 permanent personnel. No new classes came while POW was there.
POW estimated that about 40% of the reserve cadets were to become pilots and, except for a few trainees for ground administrative jobs (perhaps 3%), the rest were to become navigator-bombardiers. Men were chosen by a physical and mental fitness examination shortly after arrival, for those duties. Enlisted trainees were to become pilots and air crewmen, percentages not known. When POW graduated, about 400 cadets including POW were sent to TAKAO Air Group for elementary flight training. Other MIE cadets went to SUZUKA, OI, CH'ING-TAO (TSINGTAO) and HIMEJI Air Groups, numbers sent to each unknown.
POW had heard that there was a detachment (BUNKENTAI) of the MIE Air Group known as the NARA detachment which was quartered in an old temple presumably in NARA. According to hearsay, the detachment was composed of enlisted trainees undergoing pre-flight training.
The MIE Air Group was located just NW of KARASU-MACHI, ICHISHI (ISSHI)-GUN, MIE Prefecture, as shown in the sketch below. The barracks area lay to the north with a drill ground in the south part of the designated area.
Barracks construction was still going on at the Air Group in early Jan 1944. POW estimated the facilities to be about 70% complete at that time.
TAKAO Air Group
POW was attached to this Air Group at OKAYAMA (TAKAO) airfield from 17 Jan 1944 to 30 April 1944, taking elementary flight training in Type 93 training plane. About 400 cadets who came with POW from MIE composed the student personnel. Permanent personnel numbered about 600, including about 300 maintenance men and 100 instructors. Of the latter, about 12 were warrant officers and about ten were officers, the rest being enlisted personnel. Plane complement was about 150 Type 93 Trainers. About 20 planes were assigned to each of the first four BUNTAI and the remainder were reserve. The first four BUNTAI comprised the cadets and flight instructors and constituted four HIKOBU for purposes of tactical organization. The lst and 2nd HIKOBU trained together, as did the 3rd and 4th, but two HIKOBU were not termed a HIKOTAI. The 11th and 12th BUNTAI were maintenance personnel, intermediate BUNTAI unknown.
There were no new classes entering TAKAO while POW was there. There had been enlisted trainees there, POW had heard, but they had gone before POW's group arrived and were not replaced by other enlisted trainees while POW was at the field.
P0W had heard that a gunnery school under this Air Group was in the vicinity of TAIKOZAN Mt, FORMOSA.
MITA Detachment of U/I Air Group
Stationed at OKAYAMA (TAKAO) Airfield early 1943. A combat-plane training outfit for enlisted air-crewmen. Used NELLs. Facilities at Airfield separate from those of TAKAO Air Group and near south corner of field.
TAICHU Air Group
Heard to have been a Type 93 Trainer elementary flight training unit stationed near TAICHU, FORMOSA.
TAINAN Air Group
POW was transferred to this Air Group on 30 April 1944 and remained there until 28 Aug 1944. The Air Group was a combat plane training unit with about 50 KATEs and approximately the same number of VALs. Student personnel comprised about 400 cadets from TAKAO, originally from MIE,
who had accompanied POW on his training course, plus about 200 enlisted air-crew trainees. The TAINAN Airfield was only a training field at the time POW was there. About half the students trained in VALs and about half in KATEs. Organization was standard. Four BUNTAI were composed of flight personnel, student and instructor, and two of maintenance men. Permanent personnel totalled about 1,600, including about 400 maintenance personnel. The Air Group was stationed at TAINAN Airfield. Pilots who completed training here with POW were sent, among other placos, to LUZON, OKINAWA, and SUZUKA.
USA Air Group
POW was transferred to this Air Group on 28 Aug 1944 and remained there as a flight instructor in KATE until the end of Dec 1944. Plane complement was about 50 KATEs and perhaps the same number of VALs. Trainees, all taking combat-plane pilot training, totalled about 70 reserve cadets, 70 regular cadets, and about 100 enlisted men. The reserve cadets, POW thought, had come from the TSUIKI Air Group, where they had had elementary flight training; they, had had pre-flight training at YOKOSUKA. Regulars were graduates of the Naval College. Permanent personnel numbered about 400, including about 20 instructors.
601st Air Group
While POW was at KATORI Airfield from early Jan 1945 to 29 March 1945, the 601st Air Group was stationed there. To the best of his knowledge, it then had only 20 ZERO 52 and functioned as permanent fighter guard for the field.
KATORI Air Group
A maintenance training Air Group.
A JILL outfit organized at KATORI in early March 1945. At KATORI it had about 10 planes. Left KATORI for KUSHIRA Airfie1d about 8 March. When POW reached KUSHIRA on 29 March, K-254th HIKOTAI had about 20 planes, but POW estimated that it was scheduled to have about 50.
A JILL 12 unit stationed at KUSHIRA with about 50 planes, about 20 of which took part in attacks against US shipping off OKINAWA. POW thought that this HIKOTAI belonged to the 701st Air Group, the Air Group possibly being based at KANOYA.
K-210th HIKOTAI (?)
A JILL 12 Unit, part of which arrived at KUSHIRA on 29 March 1945, reputedly from the MEIJI Air Base in the NAGOYA area. (IN: POW was fairly certain of his identification; but as the 210th Air Group is known to have been based at MEIJI, it is possible that he confused the Air Group or a detachment from it with the HIKOTAI.)
Reported to be a JUDY outfit; location and further details unknown. As far as POW knew, it was not at either KATORI or KUSHIRA while POW was at these fields.
KUSHIRA Air Group
Heard that it was a training Air Group for maintenance nen.
Combined Training Air Groups
POE believed that there were seven, numbered 12 through 19 but omitting 14. He said that TAKAO, TAINAN, SHINCHIKU, and TAICHU were in the same combined Air Group, possibly the 12th, Hq at TAINAN. TSUCHIUKA and MIE Air Groups, he thought, were in the 19th. Others unidentified. (IN: POW was not certain of designations of Combined Training Groups. What he called 12th appears to be the 14th.)
A set of photos I recently discovered in the "Asahi Shimbun" collection.
According to the caption:
"KANOYA, JAPAN - MAY 01: A kamikaze attack aircraft carrying a torpedo under the body of the plane takes off at the Imperial Japanese Navy Air Base circa May 1945 in Kanoya, Kagoshima, Japan. The air base was the centre of the Japan's suicidal Kamikaze Attacks, along with the Imperial Army Air Force Chiran Air Base at the end of the Pacific War. (Photos by Yasuo Tomishige/The Asahi Shimbun via Getty Images).
The Nakajima B6N "Tenzan" (Jill) belong to the 131 Kokutai as indicated by their tail marking.
The unit was organized on July 10, 1944 in Yokosuka by combining the Recce 11 Hikotai equipped with Nakajima C6N "Saiun" (MYRT) and Yokosuka D4Y reconnaissance with the Sento 851 Hikotai that was equipped with Nakajima J1N "Gekko". Their next base was Katori, Chiba Prefecture. From the end of July, the "Gekko" of the 851 flew air defence and patrol missions in the Okinawa area but the 131Ku was re-organized on November 15 and this time it was equipped with carrier bombers and attackers. The two previous hikotai were replaced by Kogeki 105 and 251 who now made up the kokutai. On December 1, 1944 the unit had 48 carrier bombers and 48 carrier attackers. Early January 1945 the unit was organized with three hikotai; 3, 105 and 251. On March 1, 1945, the Sento 804, 812, 901, all night fighter units, were attached to the 131Ku and the previously mentioned hikotai equipped with attack bombers and became: Kogeki 5, Kogeki 254 and Kogeki 256. The night fighter units were very active during the Okinawa campaign together with the bombers. On April 1, 1945 the unit had 48 carrier bombers, 48 carrier attackers and 96 night fighters. The Kogeki 254 had aircraft numbers from 01 to 49 while the Kogeki 256 numbers from 50 to 99. Throughout its history the 131Ku operated: Zero-sen, Zero night fighters, "Gekko", Val, "Suisei", "Suisei" night fighters, "Tenzan", "Ryusei" and "Saiun".
The 131Ku together with "Tenzan" from other kokutai, also organized Kamikaze groups based in Kushira base, Kagoshima Prefecture and participated in the "Kikusui" attacks. The first group of nine "Tenzan" from the 254 relocated to Kushira base on March 30 and were named "TenO-tai" (Heavenly Cherry Blossoms). On April 1 and 2 attacked enemy ships in the Okinawa area but only two survived. The combined "Tenzan Unit" took part in the 1st Kikusui on April 6. Two "Tenzan" from the 131Ku, 254 named "Raifu Raigeki-tai" (Thunder Wind Torpedo Unit), three from the 256 named "Jinpu Raigeki-tai" (Squall Torpedo Unit) and four from the 701Ku. Also participated in the 3rd Kikusui of April 16 but this time six "Tenzan" from 701Ku and one from the 901Ku. On May 11 it was the 6th Kikusui and ten "Tenzan" from the 931Ku took part. All the above mentioned "Tenzan" that took part in Kikusui missions were equipped with 800kg bombs, not torpedoes.
Considering all the above information (from Akimoto Minoru, Model Art #458 and Japanese Wikipedia), the aircraft in the photos with tail number "131-64" belongs to the Kogeki 256 of the 131Ku and is NOT taking part in a suicide mission but rather a conventional torpedo attack.
Tamiya Nakajima J1N1 "Gekko" in 1/48, based in Borneo, credited with two victories. The plain IJN Nakajima camo is not evident to shade in order to give some relief to an otherwise monochromic green. I did rivet the plane and used Fine Molds 20mm barrels for the guns, otherwise, out of the box!
While Force B was patrolling, its diversion unit (OKI, or 2d CHUTAI) became separated from the attack unit, then sighted and approached the direct escort unit of Force A. At this moment the attack unit also sighted the enemy, turned right, and approached the medium attack plane unit of Force A. During this maneuver the 3rd (YAMAMOTO) SHOTAI was delayed a little, and the attack unit became drawn out.
Immediately after the attack unit begun to approach the enemy, the diversion unit was engaging A's direct escort unit (in an overhead approach). The latter broke away and came up in front of the medium attack plane unit in an attempt to attack Force B's attack unit, but were unsuccessful (though they were of some hindrance to the later attacking SHOTAI of Force B). SHOTAIs 1, 2, and 3 were able to make an effective, concerted assault.
1. The mission of the diversion of Force B was to cover the attack unit, but it became separated through poor communication; to leave the attack unit unprotected while it made a run was poor tactics. The diversion unit on patrol should fly above and a little to the rear to cover the attack unit, but just before the run it must pull ahead of the attack unit; the same tactics apply to the direct escort of medium attack planes. Keeping a close liaison at this juncture is a necessity; (a difficult maneuver).
2. Since the planes' formation is the basis of aerial combat between formations of planes, it is very important to exert every effort to maintain formation.
Essentials of formation flying: 1. Speed and precision, 2. A formation that is too tight is better than one that is too spread out, 3. To arrive too early is better than arriving late.
3. The diversion unit in patrol formation follows the attack unit; its mission is further complicated by its being required to fly ahead when the enemy is sighted. For this reason, a reciprocating patrol () might be carried out at right angles to the direction from which the enemy is expected, and the diversion unit placed on the side towards the enemy. If the diversion unit is stationed above and diagonally to the rear in the patrol formation, it will be in front of the attack unit. It is also thought that maneuvering will be facilitated by this disposition. (Lt. (jg) MASUDA)
A direct escort unit (KO fighters) must be attached to the attack unit (OTSU fighters), and the diversion unit (KO fighters) kept separate. The direct escort unit (TN: This is presumably the subject of the sentence, although the Japanese text is extremely vague.) must seize any good opportunity for checking and disrupting the enemy and then attack. The diversion unit will have as its mission the direct protection of the attack unit; its duties will be reduced and its mobility facilitated. However, since the missions of the attack and diversion units are inseparably interrelated, it is needless to emphasize the importance of preserving the closest coordination of movement between them.
Force A's direct escort unit set out for the attack over CHIBA. While it was still gaining speed in an effort to take up its position as direct escort for the medium attack plane unit, Force B's attack unit approached and attacked the bombers. By the time the attack unit had climbed ahead, the direct escort unit was in its prescribed position and ready for a run.
As the 1st and 2nd SHOTAI were weaving, Force B's attack unit again came in for an attack. The 1st and 2nd SHOTAI of the direct escort unit engaged them. The 1st and 2nd SHOTAI, above them with an altitude advantage of 700 meters, engaged the diversion unit of Force B. As a result, the attack unit's run was pulled flat.
In general, the direct escort unit of Force A maintained good position and was able to prevent any effective attacks.
While on patrol over its YOKOSUKA base, Force B sighted 6 fighters (Army SHOKIs) (TN: TOJO) in the direction of CHIBA at a distance of about 4000 meters. Though very near to them, the diversion unit (MASUDA CHUTAI) mistook these planes for the "enemy", became separated from the attack unit, and made a run on the fighters. However, realizing their mistake, the hastily turned, and attempted to rejoin the attack unit; but since they were already at some distance, only the 2nd SHOTAI was able to catch up and fly ahead of the attack unit.
When the enemy was actually sighted, the 2nd SHOTAI made an overhead attack on the enemy's direct escort unit. The attack unit beat off an attack by Force A's direct escort unit and attacked the medium attack plane unit (but was again attacked by part of the direct escort unit).
Hereupon, the 1st SHOTAI of Force B's diversion unit also joined the fight, but was unable to give the attack unit complete protection.
1. It is exceedingly poor tactics for the diversion unit to part from the attack unit;. The diversion unit bears an inseparable relationship to the attack unit; it must maneuver so as to be in advance when the attack unit starts its approach.
2. When approaching the bombers, the attack unit should roll over with an altitude advantage of 500-700 meters (TN: make its run), and pull out immediately in front of them.
When an altitude advantage of about 1000 meters has been regained, and an air speed of about 130 knots (indicated) has been reached, roll over, and another approach will be easy. Rolling over for the run after approaching with an altitude advantage of 1000 meters and at an air speed of 170-190 knots (indicated) makes for over-acceleration and rather difficult deflection firing.