Comparing: VK 30.01 (H) vs. O-I Experimental

An order for developing the vehicle was placed on September 9, 1939. Over the course of its development, Henschel engineers actively used elements of the D.W. II project. The first two prototypes were ready in March 1942; another two were built by October the same year. Hulls of the prototypes underwent trials at the plant proving ground. After the trials, two prototypes were converted into heavy tank destoyers. Six turrets manufactured by the Krupp company were placed at the Atlantic Wall.

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.