From its inception, the project was a joint Imperial Japanese Army Air Service (JAAF)/Imperial Japanese Navy Air Service (JNAF) venture. The JAAF wanted a new design to be drawn up. The JNAF, on the other hand, felt the design should mimic the German "Komet" because it had already proven to be a stable aerodynamic body. It was the JNAF which won and issued the "19-shi" specification in July 1944 for the design of the rocket-powered defence fighter. The contract went to Mitsubishi "Jukogyo" KK, which would produce both the JNAF version the J8M1 "Shūsui" and the JAAF version Ki-200.