The Kayaba gliders were developed to investigate the characteristics of tailless aircraft, and other than a 1938 private venture, the HK-1, were sponsored by the Japanese Army. The HK-1 was designed by Dr. Hidemasa Kimura based on an idea by pioneer aviator Kumazo Hino, the first person to fly an airplane in Japan, in 1910. Tests with the HK-1 led to Army interest, and Dr. Kimura, later to become Professor of the Science and Engineering Department, Nippon University, during the post-war years, responded with the KU-2. Working with Kayaba's Chief Designer Shigeki Naito, Kimura designed a single-seat model that flew 270 flights between October 1940 and May 1941.

Designed bv Dr. Hidemasa Kimura, manufactured by the Ito Airplane Works in 1938, the HK-1 was a private venture to investigate tailless characteristics. Wing span was 34.8 feet, length 11 feet, weight 448 pounds.

Dr. Kimura, in collaboration with designer Joji Washimi, next produced a more advanced version of the KU-2 in 1941. The KU-3 was a two-place experimental craft with no vertical control surfaces. The leading edge of the wing was "cranked," incorporating sections of different angles of sweepback, with three control surfaces arrayed along the trailing edge of each wing. Over 60 flights were flown before the lone KU-3 crashed in 1941.

Dr. Kimura carried the KU-3 design one step further. A powered version, the KU-4, was designed, but abandoned by the Japanese Army before it was built. It marked the end of any significant tailless aircraft development in Japan until 1944.

The appearance of American B-29 Super fortresses over Japan in 1944, produced an urgent need for a high performance interceptor. Inspired by the Me 163 Komet, Mitsubishi engineers, using a German Walter HWK 109-509 rocket motor and an instruction manual for the Me 163B, designed the J8M1 Shusui (swinging sword) for the Japanese Navy, and the Army version, designated Ki-200. A glider version, the MXY-8, was also developed to provide data on handling characteristics of the J8M1 and to be used for rocket pilot training. A prototype glider was flown in early 1945, and subsequently placed in production. Similar training gliders were planned for the Army's Ki-200.

These MXY-8 Shusui gliders were used to train pilots to fly the J8M1 rocket interceptors. Glider training took place at Kashiwa Air Base in Japan. The Japanese Army called the glider "Shusui Light Glider"; later on heavy gliders, about the same weight, structure, and appearance of the rocket fighter, were programmed.

A special corps of potential rocket pilots began training at Kashiwa Air Base in the spring of 1945, conducting test and training flights in preparation for the day when the rocket-powered fighters would be available. That day never came. The J8M1 first flew on July 7, 1945, but an engine failure shortly after takeoff resulted in a disastrous crash, killing the test pilot. There were no more flights prior to war's end, although J8M 1 production was underway, and a J8M2 and an advanced Ki-200, designated Ki-202, were planned.