Comparing: KV-1S vs. O-I Experimental

A further modification of the KV-1 heavy tank series developed in the summer of 1942. It passed into Red Army service on August 20, 1942. Compared to its predecessors, KV-1S had several design features which allowed for the tank’s weight to be reduced to 42.3 tons. Also, the KV-1S had increased top speed, maneuverability, and durability. However, the 76-mm ZIS-5 gun remained. This, coupled with reduced and inefficient armoring, made the new vehicle basically equal to the Т-34 in terms of battle performance. A total of 1,083 vehicles of this modification were manufactured. This tank was widely used on all fronts of the Great Patriotic War.

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.