Mitsubishi A5M "Claude", Ensign Kashimura Kan-ichi

For too long, Japanese WWII aircraft have carried a bad reputation and have been undeservedly criticized of being poorly designed and easy to shoot down. This claim has often been repeated in numerous publications and even on more recent YouTube channels and FB pages. Understandably, language and accessibility limitations hindered historians in the past and depending solely on one-sided narratives, Allied pilots have frequently been depicted akin to the heroes in "Western films," where a single shot from the heroic cowboy resulted in at least ten "Indians" to fall dead from their horses. This inglorious image of Japanese aircraft getting "flamed" in droves, was only partially corroborated during the final months of the war when obsolete Japanese aircraft types flown by virtually untrained pilots were pitted to their detriment against the best Allied fighters and pilots.
Only in recent years, owing to the relentless efforts of aviation historians such as M.J. Claringbould*, who extensively explore original Japanese sources—not merely Allied sources, as was typical previously—that Japanese WWII aircraft gradually receive a much fairer place in the annals of aviation history. And little by little it becomes apparent that this is perhaps a case of "survivor bias", where only the shot down and badly damaged, often on the ground, Japanese aircraft are taken into account, while those that managed to make it back to base are ignored. Today we present one such case, famous to those well-versed in Japanese aviation history but seemingly completely unknown to many younger researchers and historians.

According to Håkan :
"On 9 December 1937 fifteen Japanese bombers escorted by eight fighters attacked Nanchang, the capital of the Kiangsi Province. Captain Wang Han-Hsun, commander of the 26th PS of the 5th PG, engaged them leading four Curtiss Hawk IIIs from Wuhan. During the engagement he shot down a Type 96 fighter. Three of his aircraft was however lost, among them Hawk no. 2604, flown by Chou Ke-Yi, who was killed. Kuan Chung-Chieh of 8th PS (Hawk no. 2606) managed to parachute from his burning aircraft but was strafed and killed by Japanese aircraft on the ground. 29th PS’s new commander, Lin Tian-Jiao, also took part in this combat and was shot down. 
The Japanese reported that eight A5Ms had battled with 20 Chinese and Soviet fighters. The Japanese claimed that they shot down twelve enemy aircraft while losing one A5M (the one shot down by Han-Hsun). Twelve more Chinese aircraft were claimed destroyed on the ground. It seems that the lost Japanese pilot was PO3c Naoshi Teramatsu of the 13th Kokutai (even if there is some uncertainties regarding the place of his death). 
PO3c Kan-ichi Kashimura of the 13th Kokutai was involved in a combat with a large number of Curtiss Hawks and after shooting down one of them, he collided in the air with another Chinese Hawk III, which already had been shot down and was falling out of control."

Hata & Izawa in "Japanese Naval Aces" continue:
"After shooting down one enemy aircraft, Kashimura's aircraft collided with another aircraft that had come in during a head-on attack, and his own aircraft started falling. However, Kashimura was able to right his plane just before it touched ground. He then proceeded to pilot his aircraft in a calm but adroit fashion, taking corrective balancing action to compensate for the almost two-thirds of his plane's left wing that had been sheared off. He was able to return to base."   

Kashimura's Mitsubishi A5M "Claude" is seen approaching Nanjing Airfield, the base of the 13th Kokutai. He covered a distance of more than 600 kilometres in about 1 hour and 20 minutes flying without a third of the port wing of his "Claude". Luckily his return was covered by a war correspondent stationed at the base.

Kashimura's "Claude" from a different angle. It was a Type 96 Model 1 carrier-based fighter or Mitsubishi A5M2a, with tail number "4-115". Although the top camouflage looks solid, it most probably sported a two tone, green and brown, top camo. In all photos, only the two "15" digits of the tail marking seem to be in white. At that time, the 13 Kokutai had all its tail numbers in white so, this is either a case of censorship or perhaps the first digit "4" was in red(?), since this was not rare when the unit used "T-" for its tail marking.

Hata & Izawa mention:

"Even landing at his base was difficult; he tried four different times before finally making it. Immediately upon touching ground, Kashimura's aircraft somersaulted and the tail of the plane was sheared off. Kashimura himself did not receive even a scratch during the entire ordeal."

In a most typical Japanese fashion, officers from his own air group (Naval Academy graduates) even criticised Kashimura saying things like, "Had he crashed en route, the aircraft's secrets would have fallen into Chinese hands. He should have crashed into an enemy runway and blown himself up."

A vintage depiction of the air battle over Nanchang detailing Kashimura's colision with Chinese Curtis Hawks III.

Reports stated he shot down one of two enemy aircraft before ramming the remaining one and in this depiction he is shooting down two enemy planes before coliding with a third.

However, ace ENS Tanaka Kuniyoshi, who was flying behind Kashimura at the time, later recalled: "Newspaper reports made it seem like he shot down one aircraft before ramming the other, but in truth, we collided early in the dogfight because he couldn't evade the enemy aircraft in time. Given the circumstances, they probably embellished the story to boost morale."

Kashimura was widely reported in Japanese newspapers and newsreels as "Kashimura, the One-Winged Returnee" and became a hero of the Sino-Japanese War. His damaged "Claude" was transported to Tokyo and remained on public display until the war's end. Considering that the tail of the plane was "sheared off" during landing, it seems that the aircraft seen in the photo on display was repaired to some extend.

Kashimura Kan-ichi was born in 1913 in Zentsūji Town, Kagawa Prefecture. After graduating from Marugame High School, he joined the Sasebo Naval Corps in May 1933. He entered the 24th Pilot Training Class in February 1934, graduating in July and joined the Kasumigaura Kokutai.

Kashimura then served at kokutai in Ōmura, Yokosuka, and Kagoshima.

The outbreak of the Second Sino-Japanese War in 1937 saw him assigned in October to the 13th Kokutai. He deployed to the Central China Front and advanced to bases in Shanghai. His first combat mission was the attack on Nanking on November 22, where he shot down two enemy aircraft (type unknown).

According to Håkan:

"Japanese aircraft attacked Nanking escorted by A5Ms from the 13th Kokutai. In this, his first combat PO3c Kan-ichi Kashimura of the 13th Kokutai claimed two aircraft. These two claims seem to have been the only ones made by the IJNAF in the area during the day.

It seems that the Japanese aircraft had been involved in combat with Soviet volunteers since during the day G. M. Prokof’ev’s group scored its first victory when six I-16s fought six A5Ms and shot down the Japanese pilot PO3c Koji Miyazaki (Pilot 29) of the 13th Kokutai. The Kurdyumov group also reported combat when 11 bombers attacked Nanking, but two or three I-16s of the Kurdyumov group chased them away from the airfield and shot down one aircraft.

One of Kashimura’s claims might have been Leitenant Nikolay Nikiforovich Nezhdanov, who according to data in the Russian Ministry of Defense archives was killed in an air battle on 22 November 1937. Leitenant Nezhdanov (born 1913) received a posthumous Order of the Red Banner in 1938."

For his December "half wing flight", Kashimura received the Order of the Golden Kite, Fifth Class, an unusual honour for a non-commissioned officer. The particular medal can be seen on the far left side of the medals he is wearing in the photo. Next to it is "Order of the Rising Sun, 8th Class", next is the "China Incident War Medal" but I can't identify the one worn on the extreme right. Leave a comment if you have any ideas. 

Also, Navy minister Yonai sent to Kashimura the following words inscribed with a brush on a photo of the Kashimura aircraft as it was being flown with only one wing: "Shidai Shigen, Shigen Shimyo" ("Enormous re-sponsibilities, enormous strength; enor-mous masterly techniques, masterful adroitness") (Hata & Izawa).

At the outbreak of the Pacific War, he was assigned to the Yokosuka Kokutai.

During the Doolittle Raid, he took off to intercept and visually identified a B-25, but mistook it for an ally based on prior intelligence and let it pass. 

In December 1942, he was assigned to the 582nd Kokutai and deployed to Rabaul. At Rabaul, Kashimura trained fighter squadron members with a harsh approach, including physical discipline, and was disliked by his subordinates.

On March 6, 1943, he was killed in action while engaging an F4F over Russell Island. His rank at the time of death was Chief Petty Officer; he was posthumously promoted to Ensign. His total aerial victories since the Sino-Japanese War stood at 10 aircraft.

*and Arawasi, of course

Nakajima Ki-44 "Shoki" In Action, 47 Sentai - video

 A short video from the NHK collection, dated January 18, 1945, features Nakajima Ki-44 "Shoki" fighters from the 47 Sentai taking off.

Check here for more.

Mitsubishi Ki-67 "Hiryu" (Peggy), "Fugaku-tai" - video

A two-part video today (from here) with some addition I made at the end of the first, featuring specially modified Mitsubishi Ki-67 "Hiryu" (Peggy) bombers of the "Fugaku-tai".
The "Fugaku-tai" unit was organized on October 24, 1944, with 26 members (11 pilots, 15 mechanics) from the Hamamatsu Bombing School, under the command of Maj Nishio. The next day, the unit received their Mitsubishi Ki-67 "Hiryu" (Peggy) bombers at the Kakamigahara Aviation Depot and the following day a departure ceremony was held. 
After a brief stop at Chyayi Airfield, Taiwan, the unit arrived to their base, Clark Field, Luzon Island, the Philippines where they begun training and maintenance. 
On November 7, five aircraft of the "Fugaku-tai" were ordered to attack enemy naval forces in the waters east of the Philippines, making their first sortie.
On the 11th, they again sortieed east of the Philippines in search of enemy carriers, but returned without locating targets due to poor weather. 
On the 13th, as Manila on Luzon Island and the Clark area came under attack by US carrier-based aircraft, the third sortie order was issued and at 17:00, Maj Nishio and three other aircraft departed Malcat Airfield. Around 18:00, approximately 400 km east of Clark, they engaged in aerial combat with about 20 F6Fs whilst locating the enemy naval group. Maj Nishio's aircraft and Sgt. Maj Kunishige's aircraft made a daring dive attack. Sgt. Maj Shimamura, Kunishige's passenger, radioed “Enemy sighted. We are diving in” before being shot down. At this time, a confirmation aircraft verified that Kunishige's aircraft had rammed and sunk a battleship. 1Lt Soga's aircraft and Sgt. Maj Yukiyasu's aircraft returned, awaiting a second attack. Sgt Ito's aircraft returned to Malcat due to engine trouble. 
On the 15th, a fourth attack was ordered against the US naval force in the waters south of Mindanao Island but all "Peggys", except one, returned to base without locating their target. 

More sorties were carried out on the 25th and 30th, but in both cases the bombers returned without locating the target. 

At dawn on December 16, two "Hiryu" took off for the seventh attack, accompanied by four escort fighters. They sought enemy ships south of Mindoro Island but failed to return. 
On January 9, 1945, the eighth attack was launched with two aircraft to attack ships in Lingayen Gulf but, failing to find favourable opportunities, returned to base. 
The following day, January 10, one "Hiryu" took off solo and plunged into the enemy fleet in Lingayen Gulf. 
Subsequently, on the 12th, having received orders for a special attack on enemy vessels in Lingayen Gulf, a single "Hiryu" took off  for the tenth attack. As the last aircraft of the "Fugaku-tai", it charged the enemy ships at ultra-low altitude and was destroyed.

For a far more detailed and comprehensive account of the unit, I'm afraid you'll have to wait for an "Arawasi" magazine article.

Aichi E13A "Jake" - video

A short video today, cortessy of our friend Patrice Fresnel, from the "Imperial War Museum" features two Aichi E13A "Jake" seaplanes at Kai Tak Airfield, Kowloon, Hong Kong, after the end of the war.

The one closer to the camera has a tail marking "CS 3-3". The "CS" was used by the lesser-known "China Area Fleet" since 1944. We know that there was a transport unit flying Showa L2Ds with tail marking "CS-number", so the "3-number" part of the "Jake" marking possibly indicated different hikotai. 

The other "Jake" has "KEA-207" tail marking which indicates that it belonged to the 901 Kokutai. 

The unit was organized on December 15, 1943, at Tateyama for patrol and ship escort missions. In the beginning, it was equipped with 24 "Nell" and 12 "Mavis" flying boats. Later it received a variety of types and in May 1945 the unit had no less than 212 planes. 

In the middle of June 1944, the 901Ku moved to Donggang, Pingtung County, Taiwan, and then to Maizuru, Kyoto Prefecture where they sent various dispatch units to different locations. The main mission of the unit was sea patrol and the protection of the southwest ship routes.

On January 1, 1945, it merged with the 254Ku, 953Ku and 954Ku and on March 1, 1945, the unit had 24 carrier fighters, 24 interceptors, 24 carrier attackers, 24 "Nell" and "Betty" bombers, 64 "Jake" floatplanes, 40 Kyushu Q1W "Tokai" and 12 flying boats. On June 1, the unit had a mixed force of 12 carrier fighters, 12 "Nells" and "Bettys", 80 "Jakes" and 42 "Tokai".

Aichi E13A "Jake" In Action, Cruiser Tone/Chikuma - video

A brief video today from the NHK news archive dated November 2, 1942, showcases two Aichi E13A "Jake" floatplanes getting catapulted on a reconnaissance mission. Note the Kawanishi E7K2 "Alf" floatplane behind the "Jake".

In the initial video, the narrator states: 

"On the 24th of August, at half past three in the afternoon, our reconnaissance aircraft, patrolling the vicinity of the Solomon Islands, spotted an enemy fleet heading north in the mist-shrouded waters east of the Solomon archipelago. Upon receiving the urgent dispatch ‘Enemy ships sighted!’, our fleet boldly headed south in pursuit of the enemy."

This would indicate that the video was recorded during "Operation 'KA' - The Reinforcement of Guadalcanal," initiated on August 16, 1942, which led to the "Battle of the Eastern Solomons". The presence of dual-cannon anti-aircraft turrets and the locations of the catapults on the port and starboard suggest that the vessel is one of the "Tone Class" cruisers: either "Tone" or "Chikuma," both of which were actively involved in the operation.

According to "combinedfleet": 

16 August 1942: Operation "KA" - The Reinforcement of Guadalcanal:

At 1800 CruDiv 8's TONE and CHIKUMA depart Hashirajima with Nagumo's Third Fleet, Carrier Strike Force, Main Body's CarDiv 1's SHOKAKU and ZUIKAKU and CarDiv 2's RYUJO, light cruiser NAGARA and ten destroyers.

24 August 1942: The Battle of the Eastern Solomons:

The Carrier Strike Force, Mobile Force, Main Body's CarDiv 1, BatDiv 11, CruDiv 8's CHIKUMA and DesRon 10 cruises NE of Guadalcanal. 

At 1100, CHIKUMA and TONE of the Vanguard Force launch seven floatplanes on a late morning search for American ships.

At 1400, CHIKUMA's No. 2 Jake, piloted by Special Duty Ensign Fukuyama Kazutoshi, discovers the American task force, but is shot down by USN fighters. Its report and subsequent messages sent by HIEI's F1M2 Pete as well as CHIKUMA's No. 5 floatplane are not picked up by the leader of carrier bomber group.

At 1430, a CHIKUMA floatplane reports the location of Rear Admiral (later Admiral) Thomas C. Kinkaid's (former CO of INDIANAPOLIS, CA-35) Task Force 16's USS ENTERPRISE (CV-6). At 1445, CarDiv 1 launches an air attack against Task Group 16. At 1550, RYUJO is located, attacked and sunk by five TBFs and 21 SBDs from Task Group 11's USS SARATOGA (CV-3). TONE is attacked unsuccessfully by two TBFs whose Mark 13 torpedoes miss the cruiser.

Mitsubishi Ki-46 "Dinah" In Action - video

On December 5, 1943, the IJNAF and the IJAAF initiated "Ryu 1 Go Sakusen" (Operation Dragon 1), aiming at the port of Calcutta. The brief video showcases a Mitsubishi Ki-46-II "Dinah" coming back from a mission before the primary attack. Unfortunately, the tail markings are not discernible, making it impossible to confirm the specific unit it belonged to; however, it might have been part of a reconnaissance operation conducted one or two days prior, or possibly one of the two 81 Sentai "Dinahs" that departed ahead of the main bombing force on December 5 and released chaff southwest of Calcutta to mislead the early warning radar systems.

Mitsubishi Ki-46 "Dinah"

A photo from the Arawasi collection showcases a Mitsubishi Ki-46-II "Dinah" adorned with the hiragana "あ" (a) in black, representing the number 36 on its tail, on the apron of the Tokorozawa Maintenance School. Note the absence of a fuselage hinomaru and the shape of the pitot tube.

The tail of a Nakajima Ki-27 "Nate" with the hiragana "ほ" (ho) representing the number 5, can be seen on the left.

Nakajima Ki-43 "Hayabusa" (Oscar), "Tsubasa no Gaika" - video

A clip today from the movie "Tsubasa no Gaika" featuring a Nakajima Ki-43 "Hayabusa" with Okawa Takashi, played by actor Tsukita Ichiro* "in the cockpit"**. An absolute pleasure to see a "Hayabusa" doing all these aerobatics! 

A shortened version of the clip has appeared on various FB pages without the original sound or any credit. The info below is from the Japanese Wiki:

『Tsubasa no Gaika』 (The Triumph of Wings) is a war film produced by Toho and released on 15 October 1942.

Synopsis

Two boys, orphaned at a young age when their father—a pilot and aviation engineer—perished in a storm during a crash, were raised as foster brothers by the wife of the crashed pilot. The elder brother aspired to become a juvenile air cadet and rose to become an ace pilot (fighter pilot) in the Imperial Japanese Army Air Force. The younger brother, after training at an aircrew training school, developed into a test pilot for the Nakajima Aircraft Company's Ki-43 (later the Type 1 Fighter "Hayabusa") at Nakajima Aircraft, growing into test pilot who excel both in development and on the battlefield. 

The narrative weaves in the untold story of developing the Army's primary fighter of the era. By featuring stepbrothers who pursue distinct paths – one as an Army pilot, the other as a civilian pilot – it crafts a success story depicting their growth: one as a frontline soldier, the other as a civilian on the home front. Furthermore, by introducing a widow who watches over the two men, it illustrates the mindset of the beautiful Yamato Nadeshiko, the quintessential Japanese woman, during wartime. 

The film was sponsored by the Army Air Headquarters. All aircraft used in filming were actual aircraft, with the exception of some special effects scenes. Furthermore, the aircraft's details, such as the sighting device and oil cooler, scenes from engine start-up through take-off to landing, and aerobatic flight, are depicted with remarkable clarity. The "Hayabusa", arguably the third protagonist, is filmed extensively and without omission over a long duration, making this work akin to a promotional video for the "Hayabusa". In this respect, it stands alongside the 1940 film "Burning Skies" and the 1944 film "Kato's Hayabusa Fighter Squadron" – both of which also utilised real aircraft extensively for filming – as an extremely valuable visual historical document. 

Furthermore, the screenplay was co-written by Akira Kurosawa, who would later become a world-renowned director, and Bōhei Toyama. The special effects scenes, like those in contemporary war films such as "The Battle of Hawaii-Malay" and "The Kato Hayabusa Combat Squadron", were handled by Eiji Tsuburaya. However, due to the cooperation of the Army, many scenes featured actual aircraft, meaning the special effects scenes were limited to crashes and shoot-downs. 

Director: Yamamoto Satsuo

Screenplay: Toyama Bonpei, Kurosawa Akira

Cast: Oka Jōji, Tsukita Ichirō, Irie Takako

Music: Hattori Ryōichi

Cinematography: Kanakura Taiichi

Production Company: Toho Film

Released 15 October 1942

Running time 109 minutes 

The dialogue between the pilot and ground crew members goes like this:

GC1: Hatsudoki no choshi was do deshita 

         (How was the engine?)

P: Aa, ii yo 

   (Oh, it was fine)

GC1: Ah so desu ka 

       (Oh, really!)

GC2: Dodai guwai wa? 

        (How do you feel?)

P: Kesaku da yo 

   (Great!)

PC2: Kaji no kiki wa? 

       (How about the controls?)

P: Mmm, ii, shikashi teppo tsunde minai to wakaran na, ima wa sukoshi karui kara 

(Hmmm, good but I'm not sure without having the guns installed, 'cause it's a bit light now) 

GC2: Sore mo so da. Shindo wa? 

       (That's right. Any vibration?)

P: Daijobu da 

   (It's okay)

GC2: Hatsudoki no kaiten wa 

       (how is the engine behaving?)

P: Yoku wo ieba, sukoshi tarinai kimo suru kedo, ma tonikaku kesaku dayo. Hisashiburi ni omou zombun tonde mita yo! 

(If I'm being picky, it feels a tad underpowered, but it's a masterpiece nonetheless. It's been ages since I've flown to my heart's content!)

*Shortly after the end of the war, on September 27, 1945, he died from methanol poisoning. He was only 35 years old.

**At 00:47 and 02:35 he is actually sitting in the rear cockpit of a Tachikawa Ki-55 trainer. But from 04:21 he is indeed bringing the plane to a standstill on his own!!!

Mitsubishi Zero-sen, 381 Kokutai - video

An unbelievably clear video today featuring pilots, ground crews and Mitsubishi Zero fighters. 

The original is here. The narator speaks Indonesian, we tried to translate what he says and we were able to come up with this: 

"In one of the airforce stations of Dainippon [Great Japan], from sunset to sunset, we always hear the sound of a plane flying. Which shows that the members of the Dainippon Navy keep training enthusiastically."

So, unfortunately no exact location is mentioned. The unit is the 381 Kokutai as indicated by the number "81" on the tail marking of one of the Zeros, let's try to figure out where the video might have been shot from the unit's history.

The 381 Kokutai was organised on October 1, 1943, in Tateyama Airfield, Chiba Prefecture, and was incorporated into the 13th Air Fleet, 23rd Air Squadron. The unit was to be assigned to the protection of the Balikpapan oil fields of Borneo so, in early January 1944, an advance party of 10 aircraft deployed to Balikpapan Airfield.

On February 20, received 36 Zero fighters and 12 Nakajima J1N "Gekko" (Irving) night fighters from the 202nd Kokutai, which relocated to the Inner South Seas.

Around that time, the main force of the 381 was based at Kendari Airfield, Celebes Island, with detachments at Sumba Island, and Ambon Island. 

In early March, former seaplane fighter pilots were incorporated into the 381 following the disbandment of the fighter squadron of the 934th Kokutai.

On March 31, the 381 suffered casualties during "Operation Desecrate One" and relocated to Davao, Philippines.

On April 1, the unit organized three hikotai: the 602 Hikotai with 48 fighter-bombers with c/o Lt Kurosawa Takeo, the 902 Hikotai with 24 night fighters with c/o Lt Matsumura Hideo and the 311 Hikotai with 48 Zero Model 52 fighters with c/o Lt Kanzaki Kunio. 

On May 15, abandoned Kendari and the main force withdrew to Balikpapan, Borneo. 

The publication "Nankai No Umiwashi-tachi" (The Imperial Japanese Navy Air Groups in the Southwest Pacific Theater) by DaiNipponKaiga, features 381 Kokutai photos taken by photographer Abe Tetsuo when he visited Sorong base, West Papua in May 1944. While the earlier photos of 381Ku Zeros show bigger and more visible tail markings like the Zeros seen seen in the video, those aircraft featured in "Nankai", show a smaller tail marking placed higher on the tail. So, if these different tail markings is any indication then the video was shot sometime between January and May 1944, probably at Kendari Airfield, the main base of the unit. 

Let's see some stills.

The begining of the video features a Model 52 Zero, fresh out of the Mitsubishi factories, with tail marking "81-165". The same aircraft can be seen in a photo taken when the unit was based in Toyohashi base, Aichi Prefecture, before the unit was dispatched to Borneo.

Another Mitsubishi-built Model 52 has tail marking "81-171" and again can also be seen in Toyohashi.

A third Model 52 with tail marking "81-163", also seen in Toyohashi. All these photos indicate that the video was shot on a date close to the relocation from Toyohashi to Borneo and Celebes.

Note the very very interesting white wing tips on these Zeros, and how irregular they have been applied.

From 00:44 two pilots are seen playing "shogi".

The sign at 00:54 says "Kaigun Sentoki-tai Shikisho" (Navy Fighter Unit Headquarters).

Aichi E16A "Zuiun" (Paul) - video

Here's a video I recently discovered of the ultimate Aichi seaplane; the Aichi E16A "Zuiun" (Paul).

Actually it's three videos from NARA I stiched together, showing the seaplane first discovered under heavy camouflage by the US 77th Infantry Division on the shores of Ormok Bay on the island of Leyte, then roughly brought to sea getting examined by US soldiers.

Note the Type 97 Mk.1 Drift Sight at 00:47.

The particular seaplane belonged to the 301 Hikotai as indicated by the number "301-02" on the tail. The unit was organised in July 1944 and was assigned to the "Zuiun" Squadron at Yokosuka. It got transferred to the 801st Kokutai in October and advanced to Cavite, Philippines, later that month. While there, it got transferred to the 634th Kokutai in November 1944.

The 634 Kokutai was organised as an unconventional seaplane and carrier-based aircraft unit operating from an aircraft carrier as its mother ship. 

During "Operation Ro" (the Bougainville Island Naval Air Battle) in November 1943, the Imperial Japanese Navy's carrier task force (Third Fleet, under Commander-in-Chief Vice Admiral Ozawa Jisaburō) suffered heavy losses when its carrier-based aircraft were dispatched to land bases.

The Navy, urgently rebuilding the "Kido Butai" (機動部隊, "Mobile Strike Force"), allocated the nine aircraft carriers usable as mobile force carriers into three groups: the First Carrier Division with three aircraft carriers, the Second Carrier Division with two passenger-cargo ship-converted carriers and one light carrier, and the Third Carrier Division with three light carriers. Each group within this First "Kido Butai" was assigned one air group. As the second phase of its rebuilding and reinforcement strategy, the 634th Kokutai was organised as a carrier-based air group operating from the battleship-converted carriers ‘Ise’ and ‘Hyuga’. The aircraft assigned were the "Zuiun" seaplane, which could also serve as a carrier-based dive bomber, and the carrier-based bomber (dive bomber) Yokosuka D4Y "Suisei" (Judy). The "Suisei", lacking seaplane landing capability, was intended for one-way operations: launched from its carrier (aircraft battleship) via catapult, it would land on another carrier or at a land-based airfield.

On May 1, 1944, the 634 Kokutai was established at Kure Airfield, with Iwakuni Airfield as its home base. It operated under the Fourth Air Fleet. Its standard complement was to be 18 "Zuiun" and 18 "Suisei" but by May 12, not a single aircraft was available. The commander of the Fourth Air Fleet, Rear Admiral Matsuda Chiaki, urgently requested from headquarters: ‘For training purposes, unmodified "Suisei" will suffice, but please send them immediately’. Subsequently, training commenced with "Zuiun" at Kure and "Suisei" at Iwakuni (using Aichi D3A "Val" Dive Bombers due to the shortage of actual aircraft). 

On May 22, the carrier assignments were finalised: the "Zuiun" unit would be assigned to the Ise (under the direct command of Commander Amaya), and the "Suisei" unit to the Hyuga (under the command of Flight Commander Hideo Emura). On June 15, orders were issued for deployment to Saipan Island. This was later cancelled. While the Fourth Carrier Division and the 634Ku were on standby, the Battle of the Philippine Sea erupted from June 19. Ozawa's "Kido Butai" suffered a major defeat, losing three carriers and the majority of its carrier-based aircraft. 

On June 23, catapult launch trials commenced. All launches were successful. "Operation East" was ordered on July 5. The "Zuiun" Squadron advanced to Yokosuka Airfield, and the "Suisei" Squadron to Katori Airfield. Fighter and attack squadrons were incorporated from the 652nd Kokutai, which was disbanded on August 1. Depending on the situation, the Fourth Carrier Division would be assigned to the Second Raiding Force, centred on the Fifth Fleet, serving as the vanguard or escort for the main mobile force.

On October 12, 1944, the Taiwan Air Battle erupted. The "Zuiun" Squadron advanced to Ibusuki Airfield, while the carrier-based aircraft squadron advanced to Kanoya Airfield. Three days later , the "Zuiun" Squadron received orders to return to its original unit. Participation in the "Kido Butai" was considered, but it was decided not to embark the aircraft. On October 19, the two carrier ships of the Fourth Air Fleet, without embarking aircraft from the 634Ku, departed from Beppu Bay as the Ozawa "Kido Butai" bound for the Philippines. They arrived in the Philippines on October 22, and were stationed at Cavite. Thereafter, they engaged in night anti-ship attacks and anti-ship patrols under Operation "Ta".

When the Kamikaze Special Attack Force commenced operations in the Philippines at the end of October, the 634Ku also formed the "Baika" Squadron and ordered special attacks on November 6.

On November 15, the unit was incorporated into the Second Air Fleet. Carrier-based aircraft squadrons disbanded (transferred to the 201st and 701 Kokutai), reconnaissance squadrons reinforced. Thereafter, in addition to its previous night anti-ship attacks, it engaged in bombing San Jose Airfield. 

On January 8, 1945, it was transferred to the First Air Fleet. It withdrew to Tung-Kang Airfield in Taiwan. Subsequently, it shifted its base from Tung-Kang to Tamsui Airfield and engaged in patrols near Taiwan and Okinawa. 

On March 26, ‘Operation Kikusui No. 1’ was launched. The 634Ku engaged in night anti-ship attacks near Okinawa. Withdrew from Taiwan to the mainland in April. Deployed Reconnaissance Squadrons 301 and 302 to Fukuoka and Kagoshima, using Koniya  in the southernmost part of Amami Oshima as a forward base to conduct repeated attacks on Okinawa.

On August 3, incorporated into the Fifth Air Fleet and formed the 32nd Kokutai.

Commanders

Amagai Takahisa, CAPT: 1 May 1944 -

Emura Hideo, LCDR : 15 November 1944 -

立見孝六郎 (Tatami Korokuro?): August 1945 - Disbanded

Kawasaki Ki-48 "Lily" and "Ne0"

The sole prototype Kawasaki Ki-48-II "Lily" with the Ne0 ramjet engine hanging under its fuselage. The pod beneath the fuselage was hollow, with the fuel and nozzle housed within the bomb bay.

As the Second World War intensified, the front lines demanded higher-performance propeller aircraft, leading to increased interest in jet engines. Almost simultaneously with the Navy commencing development of its turbojet engine, designated ‘TR’, the Army and the University of Tokyo Aeronautical Research Institute also established specialised departments and began research.

Engineer Hayashi Teisuke was appointed from the Army's Second Aeronautical Research Institute to lead the jet engine development effort on a one-year contract basis. In mid-November 1942, a team led by Hayashi, comprising nine subordinates from Kawasaki, commenced development. Alongside the main engine concepts proposed by the Tokyo Aviation Research Institute – the Ne* 101 motorjet and the Ne 201 turboprop – it was decided to develop motorjets and turbojets for auxiliary engines. As the characteristics of the engine types were unknown, it was decided to produce both compressor types: axial-flow and centrifugal:

1. ‘Ne1’ two-stage axial-flow motor jet

2. ‘Ne2’ single-stage centrifugal motor jet

3. ‘Ne3’ three-stage axial-flow turbojet

4.  ‘Ne4’ single-stage centrifugal turbojet, and

5.  ‘Ne0’ ramjet for fundamental research.

The Ne1 and Ne2 were auxiliary engine variants of the Caproni Campini-type engine-jet. They were intended for installation either aft of the fuselage in single-engine propeller fighters or behind the engine nacelle in twin-engine propeller aircraft.

The Ne3 and Ne4 were both primarily targeted for installation in single-engine or twin-engine propeller-driven fighters.

Work proceeded at considerable speed, with drawings largely completed within approximately six months. 

The Kawasaki Ne0 ramjet engine.

The Ki-61 "Hien" was proposed as the primary candidate for a test aircraft**, with the Ki-45 Kai "Toryu" twin-engine fighter as the second choice. However, at a time when even a single front-line aircraft was desperately needed, neither could be obtained. Consequently, the slow-speed Ki-48 Type II twin-engine bomber "Lily" had to be used.

To minimise airframe modifications, a design utilising bomb racks to suspend the engine beneath the fuselage was developed with the cooperation of aircraft designers Imachi Isamu and Kitano Jun.

Illustration from Encyclopedia Vol. #IV

Ne0 was finished in November 1943, and on the morning of 23 December 1943, test pilot Kataoka Saizaburo*** took off from Kawasaki with engineers Hayashi and Nozu aboard. However, ignition of the combustor failed, necessitating a landing. After servicing the ignition plug, they took off again in the afternoon.

This time, the combustor ignited easily. The aircraft accelerated, delivering considerable shock to the passenger seats and momentarily causing the nose to pitch up. It then maintained high-speed cruise at an altitude of 800 to 1000 metres for approximately ten minutes before landing.

Subsequent multiple flights reportedly yielded preliminary results. Though abandoned after flight testing concluded, the entire airframe was transferred to the Army's Second Aeronautical Research Institute in July 1944. 

Following Ne0 testing, research focus shifted to two of the four Ne1 to Ne4 variants—Ne3 and Ne4—with ground-running tests conducted on prototypes. However, due to the worsening war situation and the acquisition of engine data from Germany, all development of these Kawasaki jet engines was suspended during the prototype consolidation in July 1944. Consequently, no aerial tests were conducted before the war's end.

Specifications

Ne0

• Type: Ramjet

• Overall length: 2,100mm

• Maximum cross-sectional diameter: 600mm

• Thrust: 60kg (altitude 2,800m)

• Air flow rate: 8.1kg/s (altitude 2,800m)

• Compression ratio: 1.12 (altitude 5,800m, 550km/h)

Ne1

• Type: Motorjet

• Compressor: Two-stage axial flow, contra-flow type

• Length from rear edge of impeller to jet nozzle: 1,050mm

• Outer casing diameter: 600mm

• Thrust: 185.5kg × 2 (altitude 2,800m)

• Airflow: 10.4kg/s (altitude 2,800m)

Ne2

• Type: Motorjet

• Compressor: Single-stage centrifugal

• Thrust: 150kg (planned)

Ne3

• Type: Turbojet

• Overall length: 2,321mm

• Casing outer diameter: 760mm

• Total weight: 309 kg + (casing weight)

• Compressor: 3-stage axial-flow

• Turbine: 1-stage axial-flow

• Thrust: 348 kg (altitude 2,800 m)

• Air flow rate: 14.9 kg/s (altitude 2,800 m)

• Compression ratio: 1.71 (5,800 m, 550 km/h)

• Rotational speed: 8,300 rpm (altitude 2,800 m)

Ne4

• Type: Turbojet

• Overall length: 1,700 mm

• Casing outer diameter: 750 mm

• Total weight: 270 kg + (casing weight)

• Compressor: Single-stage centrifugal

• Turbine: Single-stage axial

• Thrust: 276 kg (altitude 2,800 m)

• Airflow: 10.35 kg/s (altitude 2,800 m)

• Compression Ratio: 1.98 (5,800 m, 550 km/h)

• Rotational Speed: 1,100 rpm (altitude 2,800 m)

*"ネ" (NE) was a common designation used by both the IJAAF and the IJNAF. At the time, both jet and rocket engines were collectively referred to as "燃焼ロケット" ("NEnsho roketo" combustion rockets).

**One can only imagine what a "Hien" would look like with a jet engine on its tail.

***A test pilot for the Imperial Japanese Army Air Force, he was responsible for the maiden flights of prototypes such as the Ki-61-II "Hien" and the Ki-78, manufactured by Kawasaki Aircraft. During the Ki-78 (Ken-3) test flight in January 1944, he recorded a top speed of 699.9 km/h, which remained Japan's speed record until the end of the war.

Kobeseiko "Te-Go" Experimental Observation Aircraft

Designed by Professor Miki Tetsuo of the Department of Aeronautics, Faculty of Engineering, Osaka Imperial University, at the request of the Army, as a short take-off and landing aircraft for artillery spotting by the Army Artillery Corps. As it was outside the jurisdiction of the IJAAF, it was not assigned a Ki number. It featured a distinctive high-wing monoplane configuration, equipped with automatic leading-edge slats spanning the entire main wing, trailing-edge Fowler flaps, and ailerons doubling as flaps. To achieve a large wing angle of attack during take-off and landing runs, the main landing gear was raised high. Large windows were fitted to the fuselage to provide a wide field of view. 
The wings were wooden with fabric covering and could be folded rearward. The fuselage featured a mixed wooden and metal frame covered in fabric, with only the nose section clad in light metal. Priority was given to short take-off and landing performance for use from hastily constructed frontline airfields, riverbanks, open spaces, and roads. Seating was arranged in a single file.
The engine was the same type as that fitted to the Kayaba "Ka-go" Type 1 observation autogyro, the Kobe Steel Argus As-10 24OH. For the "Te-go" observation aircraft, Kobe Steel also manufactured the airframe, with the prototype completed in 1942. However, it had a landing gear failure during test flights. Consequently, the Army adopted the "Ka-go" observation autogyro for this role, and development of the "Te-go" was cancelled.
Plans also existed for a three-seat Army artillery observation aircraft (abbreviated RGK), but only the design was completed and no actual aircraft were built. It would be a large observation aircraft equipped with the Nakajima ‘Kotobuki’ Type 3 5501P engine, with a wingspan of 21.00m, length 12.80m, and height 2.70m.

General characteristics
Single-engine, high-wing monoplane, land-based aircraft
Crew: 2
Length: 9.50m
Height: 3.00m
Wingspan: 13.00m
Wing area: 20sq m
Maximum take-off weight: 1,130 kg
Wing loading: 56kg/sq m
Power loading: 4.52kg/hp
Powerplant: 1 X Kobe Steel Argus As-10 air-cooled inverted V-8, nominal output 240 hp, take-off output 250 hp.
Propeller: Wooden fixed-pitch, 2-bladed, diameter 2.75 m

Performance
Maximum speed: 180 km/h
Endurance: 6 hours
Service ceiling: 8,2 80m (27,165 ft)
Armament: One 7.7 mm flexible machine gun (mounted above rear seat, retractable, with two spare magazines)

Illustration from "Nihon Rikugun Shisakuki Taikan" (All the Experimental Aircraft in Japanese Army), by Akimoto Minoru, Kantosha 2008

Mitsubishi Army Experimental "Tobi" Reconnaissance Aircraft (Company designation 2MR1)

In 1926, the IJAAF sought competitive proposals from Nakajima, Kawasaki, Ishikawajima, and Mitsubishi to replace the Type Otsu 1 Reconnaissance Aircraft (Salmson 2-A.2s). Mitsubishi, with the assistance of Dr Alexander Baumann, a professor at Stuttgart University, and former designer of Riesenflugzeug for Zeppelin-Staaken, assigned Nobushiro Nakata as chief designer and Satsuo Tokunaga as his assistant. The result was a radical design for a sesquiplane, having the upper wing set unusually high above the slender fuselage, connected with a unique type of center-section and interplane struts. As one of the Mitsubishi bird series projects in 1925-27, this aircraft was given the name “Tobi” (black kite ).

The first prototype was completed in July 1927. In the hands of test pilot Jiro Itoh the aircraft achieved speed of 227km/h (123kt) faster than the Army's specified 200km/h (108kt). Mitsubishi had high expectations for the new aircraft, but during an official qualifying test flight by the Army at Tokorozawa, an undercarriage shock strut failed and during the landing the aircraft was badly damaged and eliminated from the competition. The Nakajima and Ishikawajima entries also failed, but the Kawasaki aircraft met the requirements and was accepted as the Type 88 Reconnaissance Aircraft (KDA-2). 

General characteristics

Single-engine sesquiplane with large gap. Metal fuselage structure with wood and metal wings, fabric covered with some plywood and thin metal on the forward fuselage.

Crew: 2 in open cockpits

Length: 9.55m (31ft 4in)

Height: 4.35m (14ft 31/2in)

Wingspan: 17.40m (57ft)

Wing area: 50sq m (538.213sq ft), upper 34.50sq m (371.367sq ft), lower 15.50sq m (166.846sq ft)

Empty weight: 1,350kg (2,9761b)

Gross weight: 2,500kg (5,5111b)

Wing loading: 50kg/sq m (10.2411b/sq ft)

Power loading: 3.5kg/hp (7.71b/hp)

Powerplant: 1 X 450-600hp Mitsubishi-Hispano-Suiza twelve-cylinder vee water-cooled engine, driving a Mitsubishi-Reed fixed-pitch two-bladed metal propeller

Performance

Maximum speed: 123kt (142mph) at 5,000m (16,404ft)

Endurance: 6 hours

Service ceiling: 8,2 80m (27,165 ft)

Armament

Guns: Two forward-firing fixed 7.7mm machine-guns and twin dorsal flexible 7.7mm machine-guns

*Note that the Wiki entry for the "Mitsubishi Experimental Tobi-type Reconnaissance Aircraft" links to the IJNAF Mitsubishi 2MR Carrier-based Reconnaissance Aircraft, a completely unrelated aircraft type which first flew in 1922.

Experimental 7-Shi Carrier Attack Aircraft (Nakajima B4N1, Y3B)

In April 1932, the Navy issued instructions to Mitsubishi and Nakajima to prototype a new carrier-based attack aircraft to replace the unpopular Type 89 Carrier Attacker. Nakajima, with Engineer Yoshida Takao as chief designer, developed the distinctive biplane Y3B equipped with the newly designed “Hikari” 73O engine. Two prototypes were built in 1933 and submitted for Navy evaluation. This aircraft featured a Gal-type upper wing and an inverted Gal-type lower wing, with the central section crossing in an X-shape relative to the slender fuselage. Furthermore, the landing gear struts were cantilevered from the lower wing's bend, representing an extremely bold structural design. The fuel tanks were exposed and removable, mounted on both sides of the fuselage, similar to those on the Nakajima E4N2 Reconnaissance Seaplane and the Nakajima A2N Carrier Fighter Model 2. At the time, the development of tri-seat carrier-based attack aircraft was a major challenge not only for Mitsubishi and Nakajima but also for Aichi and the Naval Technical Arsenal. Particularly, the selection of a reliable, high-horsepower engine proved difficult, preventing the establishment of a definitive design. Two prototypes were built in 1933 with the short designation B4N1*, and delivered to the Navy for evaluation but they failed to win Navy approval. Mitsubishi submitted its 7-Shi Carrier Attack Aircraft but it crashed on takeoff due to engine failure. Because of these failings, the Navy began with a new design competition for a 9- Shi Carrier Attack Aircraft.

Check this amazing scratch-built model here.

General characteristics
Crew: 3 (pilot, navigator/bomb aimer and gunner)
Length: 10 m (32 ft 10 in)
Wingspan: 14 m (45 ft 11 in)
Height: 3.80 m (12 ft 6 in)
Wing area: 50.0 m2 (538 sq ft)
Empty weight: 2,000 kg (4,409 lb)
Gross weight: 3,800 kg (8,378 lb)
Powerplant: 1 × Nakajima Hikari 2 9-cylinder radial engine, 520 kW (700 hp)
Propellers: 3-bladed

Performance
Maximum speed: 220 km/h (140 mph, 120 kn)
Stall speed: 93 km/h (58 mph, 50 kn)
Endurance: 6 hr
Service ceiling: 5,500 m (18,000 ft)
Time to altitude: 12 minutes to 3,000 m (9,800 ft)

Armament
Guns: 1 × flexibly mounted 7.7 mm machine gun
Bombs: 1 × 800 kg (1,760 lb) torpedo, or 1 × 800 kg bomb, or 2 × 250 kg bombs

*Francillon, Model Art #327 and others mention that the designation was "B4N1", only Mikesh-Abe mention that it was "B3N1". Considering that the Mitsubishi entry in the 7-Shi competition was designated B4M1 agreed by everyone including Mikesh-Abe and that the officially adopted type was the B4Y1 (also agreed by everyone), it is safe to conclude that the "B3N1" designation mentioned in the Mikesh-Abe book was a missprint. The Wiki entry needs correcting...

Nakajima Bulldog Fighter

Nakajima's design for a parasol-wing fighter, along with those of other companies competing for the Army's requirement for a new fighter, met with early uncertainties. Eventually, Nakajima's design was further developed and became the successful Army Type 91 Fighter, but in the interim, Nakajima, in 1930, bought the licence-manufacturing rights for the Bristol Bulldog. This aircraft was thought by Nakajima to be an ideal replacement for the ageing Type Ko 4 Fighters. Like the earlier N-35 Reconnaissance Aircraft, this project was supervised by the same French team headed by Andre Marie, assisted by Maxime Robin and others. Because this was a British-designed aircraft, Leslie G. Frise of the Bristol Aeroplane Co and his assistant H.W. Dunn were invited to Japan to assist. The first prototype was completed in June 1930, followed soon after by the second prototype. The design was based upon the Bristol Bulldog Mk. II, but differed by having each engine cylinder covered by separate fairings, the interplane struts were changed to the N type as used on the Bristol Bullpup, and struts were used to brace the tailplane. The Nakajima Jupiter engine was substituted for the Bristol-built Jupiter. After two prototypes were built, some of the parts were found to have insufficient strength for safe flight, therefore Nakajima Chikuhei grounded them. As a consequence, they were never submitted to the Army for evaluation; however, Nakajima's design for the parasol-wing Type 91 Fighter had by now achieved success. The two Bulldogs were eventually donated to the Navy, at the outbreak of the Shanghai Incident, for structural research purposes.

General characteristics

Single-engine single-seat fighter biplane. Metal structure with fabric covering.

Crew: Pilot in open cockpit.

Length: 7.54m (24ft 9in)

Span: 10.36m (34ft)

Height: 2.99m (9ft 91/2in)

Wing area: 28.5sq m (306.781sq ft)

Wing loading 56.1kg/sq m (11.51b/sq ft)

Power loading 3.55kg/hp (7.81b/hp)

Empty weight: 1,000kg (2,2041b)

Gross weight: 1,600kg (3,5271b)

Powerplant: 450-520hp Nakajima Jupiter VII nine-cylinder air-cooled radial engine, driving a two-bladed wooden propeller.

Performance

Maximum speed: 148kt (170.3mph) at 3,000m (9,843ft)

Climb to 5,000m (16,404ft) in 11 min

Service ceiling: 7,650m (25,098ft)

Aichi B7A1 "Ryusei" (Grace) by Jan Voorbij

Aichi B7A1 "Ryusei" (Grace)

Dive bomber / Torpedobomber

Pre-production plane: 1 of 9 prototypes

Imperial Japanese Navy, Kougeki (attack) 5th Hikotai, 752nd Kokutai, April/May 1945 and later 1945 Katori Naval Air Base April 1945 till the end of May 1945, then moved to Kisarazu Naval Air base. Captured by US troops in August 1945.

Fujimi 7AF1, 1:72

- Jan Voorbij, Holand -

Kawasaki Experimental Carrier Reconnaissance Aircraft

In March 1927, the Navy decided to manufacture an experimental aircraft funded by a program sponsored by the Kaibo Gikai (Maritime Defense Volunteer Association), and named the project: 'Research of Material for All-metal Aircraft'. Kawasaki was awarded the project by the Navy. It was to be a single-engine carrier reconnaissance aircraft having an all-metal structure with fabric covering. It had a fully cantilever parasol wing with marked sweepback, and large area slotted flaps, the first in Japan and probably the first in the world. At that time, no monoplane existed for carrier-based aircraft and there were certainly none with cantilever wings and slotted flaps. The fuselage was unusual being almost triangular in the cross section. The structure of the aircraft was heavily influenced by Dornier design practices. 

Design begun in March 1927 and completed in June 1928 under the leadership of Junichiro Nagahata and his assistant Hiroshi Sato. Both engineers had been in charge of aircraft design at the Aviation Research Department, Naval Technical Research Institute. The aircraft was built at the Kawasaki Dockyard, with the construction being completed in September 1928. Flight tests began in March 1929 at Kasumigaura under the control of Navy Cdr Sakae Yamamoto. However, tests were suspended after very few flights because of problems with flap operation. The flaps were considered to be a major feature of this aircraft and their use at such an early date deserves to be recorded in aeronautical engineering history. But early suspension of the tests without further refinements to the flaps, coupled with top-secret security, resulted in the lack of public awareness and has deprived this design of its rightful place in history. With this aircraft Kawasaki's affiliation with the Japanese Navy ended, and the company became solely a manufacturer of Army aircraft and a few civil types.

General characteristics

Single-engine cantilever parasol-monoplane with slotted flap system. All-metal construction with fabric covering.

Crew: two in open cockpits

Length: 10.65m (34ft 111/2in)

Span: 16.60m (54ft 51/2in)

Height: 3.18m (10ft 51/4in)

Wing area: 43.70sq m (470.3 98sq ft)

Wing loading: 41.2kg/sq m (8.41b/sq ft)

Power loading: 4kg/hp (8.81b/hp)

Empty weight: 1,200kg (2,6451b)

Gross weight: 1,800kg (3,9681b)

Powerplant: 450-600hp Mitsubishi-Hispano-Suiza twelve-cylinder vee water-cooled engine, driving a two-bladed wooden propeller.

Performance

Maximum speed: 142kt (164mph) at sea level

Service ceiling: 10,000m (32,808ft)

Endurance 3 hours

Multi-view illustration from Encyclopedia Vol.4

Mitsubishi Type 10 Torpedo Bomber 1MT1

An 1MT1N belonging to the Kasumigaura Kokutai as indicated by the letter "R2 on its tail.

The Type 10 Torpedo Bomber (company code: 1MT1. The number ten refers to the 10th year of the reign of Emperor Taisho, i.e. 1921) was the third* aircraft designed by former Sopwith designer Engineer Herbert Smith in Japan and was Japan's first domestically produced torpedo bomber. The first prototype was completed at the Nagoya Factory on August 9, 1922. On the same day, it was test flown by pilot William Jordan and armed with a 908  lb dummy torpedo, it successfully completed its maiden flight of approximately 30 minutes at the factory airfield. Subsequently, the second prototype was completed, and further trials were conducted at Kasumigaura Airfield in November. 

It was a fixed-landing-gear, single-engine, single-seat aircraft with a wooden frame covered in fabric. The first prototype was fitted with a 450-horsepower Napier Lion engine (hence the letter N in the 1MT1N designation), while the second aircraft was equipped with a 370-horsepower Lorraine engine (indicated by the L in the 1MT1L designation).
The first model was approximately 7 kg heavier due to the engine's weight, but its greater power enabled a maximum speed 13.5 knots faster under light load (1,605 kg) and a climb time to 3,048 meters reduced by 4 minutes and 12 seconds. Consequently, the type equipped with the Napier Lion engine (1MT1N) entered production, with 10 aircraft manufactured in fiscal year 1922 and 10 in fiscal year 1923, totaling 20 units. 
This Type 10 Torpedo Bomber was characterized by its adoption of a triplane configuration and its single-seat design, which meant it possessed absolutely no defensive armament against enemy fighters or other threats. The triplane configuration had been employed during the First World War in aircraft such as the British Sopwith Triplane fighter and the German Fokker Dr I fighter. It offered advantages in terms of reducing airframe size, improving maneuverability, and increasing payload capacity. The 1MT was adopted precisely for these advantages. It surpassed the biplane Blackburn Swift carrier-based torpedo bomber and Sopwith Cuckoo carrier-based torpedo bomber in agility and maneuverability, while its speed and climb rate exceeded those of the Type 10 Carrier Reconnaissance Plane (Mitsubishi 2MR). However, the triplane configuration also presented the problem of increased overall height. In the case of the 1MT, when loaded onto the aircraft carrier Hosho, its height proved excessive, leaving insufficient clearance beneath the hangar ceiling and causing difficulties in handling within the ship. Being single-seat and lacking machine guns was a trait shared with the imported Swift and Cuckoo, but practical trials demonstrated the necessity for defensive armament. Consequently, development of its successor, the biplane, two-seat Model 13 Carrier-based Attack Aircraft (Mitsubishi B1M), commenced urgently and the 1MT disappeared from the list of aircraft in service in 1924. 
Among the three Type 10 models designed by Engineer Smith, this was the shortest-lived. However, during its service, LTJG Kikuchi Tomozo(?), an instructor at Kasumigaura Air School, successfully ascended to an altitude of 7,620 meters in an 1MT equipped with an oxygen inhalation apparatus on July 4, 1923. This surpassed the Japanese altitude record set five days earlier by LTJG Ohashi in a Type 10 carrier fighter. Furthermore, on December 5 of the same year, this aircraft achieved the first successful aerial launch test of the 18-inch (45cm) domestically produced torpedo. This torpedo, developed at the Yokosuka Naval Arsenal based on the Type 44 45cm naval torpedo, saw its prototype completed in 1921. Following over fifty launch trials conducted by LT Akashiba and LTJG Kikuchi using the Type 10 Torpedo Bomber, it was confirmed that both the diving and running performance were significantly superior to the existing 14-inch short torpedo, leading to its adoption as the Type 44 Aerial Torpedo. It remained in service until around 1934, when it was replaced by the Type 91 Aerial Torpedo, developed from the outset as an aerial torpedo. This torpedo was transitional in nature for an air-launched type, and the 1MT itself proved short-lived. Nevertheless, its contribution in paving the way for air-launched torpedo attacks, which later achieved numerous combat successes, cannot be forgotten.

General characteristics
Single-engine triplane carrier-borne torpedo carrier. Wooden structure with fabric covering. Non-folding wings.
Crew: One pilot in open cockpit
Length: 9.779m (32ft lin)
Wingspan: 13.259m (43ft 6in)
Height: 4.457m (14ft 71/2in)
Wing area: 43sq m (462.863sq ft)
Wing loading 36.1kg/sq m (7.31b/sq ft)
Power loading 5.56kg/hp (12.21b/hp)
Empty weight: 1,370kg (3,0201b)
Gross weight: 2,500 kg (5,511 lb)
Powerplant: 1 × Napier Lion , 336 kW (450 hp)

Performance
Maximum speed: 209 km/h (130 mph, 113 kn)
Cruising speed 130 km/h (81 mph, 70 kn)
Climb to 3,050m (10,000ft) in 13min 30sec
Service ceiling: 6,000 m (19,680 ft)
Endurance 2.3 hours

Armament
1 × 457 mm (18 in), 800 kg (1,764 lb) torpedo

*The other two aircraft were the Mitsubishi 1MF carrier fighter and the Mitsubishi 2MR carrier-based reconnaissance aircraft.

Artwork by Nohara Shigeru of a Kasumigaura Kokutai 1MT1N featured in Model Art #553.

A photo of an 1MT1 without a tail marking I spotted on the net. Is it undergoing trials? Could it be the 1MT1N prototype with pilot William Jordan climbing in the cockpit and the dummy torpedo hanging on the belly? Note the two smaller oppenings under the exhausts and the bigger one behind them mirroring the port side seen in the previous photo.

On the other hand in this photo from Wiki, the cowling openings are different. Could this be one of the 1MT1L aircraft with the Napier Lion engine?

One of the 1MTs was converted into a seaplane by Ando Aeroplane Research Studio at Shin-Maiko beach, Chita Peninsula, Aichi Prefecture, in 1926 and was used as a passenger transport and pilot trainer.

In the 2015 Modelling Show in Shizuoka, I spotted a fantastic 1MT1 built by Tanaka Yoshihiro of Stall. (Marusan 1/50 kit seen below)