Comparing: O-I Experimental vs. Excelsior

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.

At the end of 1942, the Churchill tank's armament was deemed insufficient. New tanks, the A31, A32, and A33 were developed as new infantry tanks. The A33 was developed by the English Electric Company. The LMS Company participated in the development of suspension for a new tank. Two vehicles, which differed greatly from each other, were manufactured. The A33 was set to go into production, but in 1943 the decision to cancel mass production of the Churchill was reversed, and the order for the A33 was not placed.