Comparing: T1 Heavy Tank vs. O-I Experimental

Development of the T1E2 started in the U.S.A. in May 1940. The vehicle was designed as a heavy tank. The distinctive features of the vehicle were a cast hull and hydromechanical transmission with a double-disc hydraulic converter. Later, the tank was designated M6. A total of 9 vehicles (1 of which was experimental) were produced. The tank never saw action.

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.