With a focus on Hien to follow I am very grateful to Jordan Rich for very kindly giving permission to share these images of a Hien found at Hmawbi, Burma at war's end and photographed by his grandfather William "Bill" H P J Rich who served as an LAC (1222102) in RAF SEAC (South East Asia Command) from March 1942 until March 1946, an impressive four years of service in a challenging environment. From February 1945 he was part of 124 Repair and Salvage Unit which eventually became 56 Forward Repair Unit (Rangoon) in the closing weeks of the war. 124 RSU moved to Hmawbi in August 1945 to support 132 RSU (his previous unit) which had been on site for just over 2 months and Jordan believes the photographs were taken there.
The Hien appears to be in the late war factory finish with solid painted upper surfaces, a finish also applied by Army depots following the decision to instigate factory painting of aircraft after June 1944. They all display the senchi hiyoshiki 'war front sign' of a white band around the fuselage forward of the tail and the wing leading edges appear to have rather deep IFF strips. The aircraft above appears to have the number '09' on the fuselage between the hinomaru and fuselage band, perhaps the 'last two' of the uncoded construction number.
I am also very grateful for the kind permission of author Simon Gifford to share another image (above) of a Hien at Hmawbi from his book 'Rapid Rundown' published by Fonthill Media in 2014. This does not appear to be the same aircraft as in Jordan's photos as the 'number' (?) between hinomaru and fuselage band is applied in a slightly different position. Simon also provided another image of a Hien taken at Changi airfield, Singapore (shown below).
The tail marking on the upturned Hien is indistinct but bears a resemblance to that of 37 Kyoiku Hikotai (教育 飛行隊 - Training [Development] Air Unit), an operational training unit for Hien. The unit is not usually associated with Burma but in 1979 Minoru Akimoto recorded its presence in Bandung, Java from 1944, engaging in combat operations, and with a part of the unit - a detachment - in Malaya at war's end. Another possibility is 7 Rensei Hikotai (練成 飛行隊 - Training Transformation Air Unit) which was based at Don Muang in Thailand but operated briefly over southern Burma during the period from September 1944 to May 1945 . That unit is reported to have been equipped with the Nakajima Ki-43 Hayabusa 'Oscar' but Rensei Hikotai often operated multiple types of fighter. As far as I know the unit insignia of 7 Rensei Hikotai is unknown*. On 11 February 1945 six Hiens reportedly from the 8th Rensei Hikotai based at Rangoon intercepted a large formation of B-24 Liberator bombers escorted by RAF Thunderbolts and US P-38s. One of the Japanese fighters was shot down by the B-24 gunners and the pilot seen to bail out. Sqn Ldr N Cameron, CO of 258 Sqn flying one of the escorting Thunderbolts made a head on pass at a Ki-61, probably the same aircraft as it went down and was awarded a half share of the claim. Another Hien was claimed by Capt H E Boggs of the 459th FS as he approached the target, identified as a 'Jill' but gun camera film reveals it was a 'Tony'. This aircraft exploded in the air but a corresponding Japanese fatality was not recorded. The 8th Rensei Hikotai is recorded in Japanese sources as a Ki-84 equipped unit based in Saigon and its insignia is known.
Hien is not much associated with Burma and although the 50th Sentai brought at least two examples into theatre for evaluation preparatory to potential re-equipment (as recounted in my Ki-61/Ki-100 Aces published by Osprey) the unit identity of these Hien at Hmawbi is uncertain. Although the airfield at Hmawbi, north-west of Rangoon (now Yangon) is usually recorded as a singular entity it was in fact a complex of airfields comprising Hmawbi East and West, Wanetchaung where the 4th Air Brigade HQ was based, Letpodaung North and Central, plus four nearby dispersal landing grounds. Under Japanese control Hmawbi had no permanent Sentai occupation (from late 1944 until early 1945 the 8th and 50th Sentai staged into it from Indo-China) but was administered by 17 Hikojo Chutai
(Airfield Company) consisting of a Chutai HQ with integral Shikihan
or administration section. The Shikihan
had a staff of about 30 personnel with a WO in command. Other sub-units were the Seibi Shotai
responsible for the refuelling and general first line maintenance of aircraft using the airfield, including overseeing the construction and repair of runways by locally requisitioned workers. Its establishment was four NCOs and 45 enlisted personnel, commanded by a Lieutenant. The Keibi Shotai
was responsible for guarding the airfield, fuel and ammunition dumps, as well as motor transport, and consisted of about 30 personnel commanded by a Lieutenant. Finally the Zairyohan
was responsible for the storage and issue of tools and other equipment, staffed by two NCOs and seven enlisted personnel under the command of a Lieutenant. The independent staffing of airfields with multiple satellite dispersals, together with the rapid staging of Sentai in Burma, was one of the main reasons that the IJAAF, significantly outnumbered in the theatre and subject to constant Allied interdiction, was able to maintain a presence there almost to the end, often staging in from more permanent bases in Thailand and Indo-China for specific operations as well as staging to forward airfields from airfields in the rear.
With very special thanks to Jordan Rich and Simon Gifford for their kind permission to share these intriguing photographs with Aviation of Japan, and to Woody Kubacki and Ronnie Olsthoorn for alerting me to them.
* Correction. In 'Imperial Japanese Army Air Service Illustrated (Fighters Edition)' (Tokyo, 2015) artist Yukinobu Nishikawa depicts a stylised '7' placed diagonally across the fin and rudder of a natural metal finish Ki-61-I captioned as being 7th Rensei Hikotai at Palembang in April 1945. The basis for this depiction is unknown.
Image credit: Photographs © 2022 Jordan Rich and Simon Gifford; tail marking schematic © 1979 Minoru Akimoto via Koku-Fan magazine.