A Kawasaki Ki-45 Kai-Hei brought to the US after the War for evaluation purposes. It retains the original paint, something quite unusual for captured and evaluated aircraft. The number "16" on the tail is from the serial number 3116 written on the plane in smaller digits signifying that it's the 16th Kai-Hei produced. (FAOW#21, p.43)
The Ki-45 Kai-Hei had a 37mm Ho-203 canon on the nose and one 20mm on the belly. The modifications and the testing was done in the First Arsenal of IJAAF. Design started in March 1943 and by May the first prototype was completed followed by 65 more by October of the same year. From that month onward the type was also produced by Kawasaki and was used for the defence of the mainland.