Japan and Thailand used the Ki-36. Cochin China, Japan, Manchuria, and Thailand used the Ki-55.
The Ki-36 was deployed to China for active service.
In 1943 the Ki-36 was very vulnerable to Allied fighters and was withdrawn to secondary areas.
Standard Advanced Trainer
The Ki-55 became the Imperial Japanese Army's standard advanced trainer.
Both the Ki-36 and Ki-55 would be equipped with bombs under the fuselage and used as suicide aircraft.
Post World War II
Three Ki-55s were found abandoned on Java and were used in the Indonesian Air Force against the Dutch.