I thought they had flying prototypes by the end of the war
There were 2 prototypes assembled
The Kikka prototypes' first flight was on August 7 (the day after the atomic bomb, was dropped on Hiroshima) at Kisarazu Naval Air Base with pilot LtCdr Susumu Takaoka.
He made a second attempt four days later (two days after the atomic bomb, was dropped on Nagasaki) but aborted the takeoff and crashed into Tokyo Bay. The second Kikka prototype never flew.
Nakajima started work on the Ki 201 Karyu without official approval or funding in late 1944, so work progressed slowly. The first flight was to be December 1945 - January 1946 so the only prototype was never finished.
BEAR