The Ki-44s were deployed primarily to the home islands, but some were located in Sumatra protecting the oil fields at Palembang.
Due to a high wing load, a high landing speed, and difficult handling the Ki-44 did some many accidents. Snap rolls, spins, and stalls were forbidden to be done in the Ki-44.
China Burma India Theater
The Ki-44 was first used in combat in the China Burma India theater. It later defended the oil fields at Palembang.
Crashing Into Bombers
In November 1944 a special unit was formed in Japan, using volunteers, that would crash their Ki-44s into B-29s.