 After the Nomonhan Incident, the shortcomings of the Type 94 37 mm anti-tank gun had become obvious, and the Imperial Japanese Army started the development of a new anti-tank gun to be more effective against the new Soviet tanks.However, as a new design would take time, as an interim measure, the existing Type 94 37 mm AT gun was modified with a longer barrel to provide for greater armor penetration.As the Type 1 37 mm AT Gun, it was introduced to combat units in 1941.