Comparing: O-I Experimental vs. Churchill I

Development of this superheavy tank was initiated by Colonel Iwakuro from the Army Ministry of Japan. The project was carried out by the Mitsubishi company, therefore the vehicle became known as the Mi-To. In the army, the tank was designated the O-I. Details of the project are largely unknown.

The A22 prototype was built by Vauxhall Motors in the fall of 1940. The vehicle first entered mass production in the summer of 1941. Early modifications had no track fenders, a different fan, and a 3-inch howitzer in the hull. A total of 300 Churchill I tanks were manufactured.