Ongoing development focused on engine upgrades to all examples to address the persistent issue of the aircraft being underpowered.

[2] During World War II, the Japanese originally intended to utilize the Ki-20s to attack the forts at the entrance to Manila Bay in the Philippines, as well as for deep penetration missions into Siberia.

For these purposes, they were armed with six gun positions and structurally enabled to carry a 5,000 kg (11,000 lb) bomb load.

These aircraft were the largest operated by the Imperial Japanese Army Air Service and their existence within it was kept secret.

A single example survived to the end of hostilities as a museum piece in the Tokorozawa Aviation Memorial Hall.