Takeo Doi designed an unusual fighter in 1939. The Japanese Army wanted a more orthodox design. However, in October 1940 the design was approved to go forward.
The engine selected was the Kawasaki Ha-201 which was two Ha-40 twelve cylinder engines mounted in tandem in front of and behind the cockpit. The forward engine drove the rear fixed pitch propeller. The rear engine drove the front variable pitch propeller.
The engines used the wings for cooling. The front engine used the port wing and the rear engine used the starboard wing.