In mid 1942 the Koku Hombu and Tachikawa Hikoki K.K. discussed creating a high altitude heavily armed fighter. The Japanese Army wanted an aircraft that had these specifications:
- Pressurized cabin
- Speed of 497 mph / 800 kph
- Range of 1,864 miles / 3,000 km
The initial design had twin booms that had two Mitsubishi Ha-211 Ru (2,200 HP) engines in a push pull setup. The armament was to be two 37 mm Ho-203 and two 30 mm Ho-105 cannons. It was anticipated that it could go 485 mph / 780 kph at 32,810' / 10,000 m.
A wooden mock up was completed in 1943. The Koku Hombu decided the project was too complex and development was to be stopped.
Tachikawa then proposed a more conventional design with a pressurized cabin. It was to have a Nakajima Ha-44 12 (2,400 HP) engine driving a six blade propeller. It was to be armed with two 30 mm Ho-105 and two 20 mm Ho-5 cannons.
The Koku Hombu ordered a static airframe, three prototypes, and eighteen pre-production aircraft that were to be designated the Ki-94-II.