Comparing: O-I vs. TOG II*

Development of the superheavy tank was started after the Battles of Khalkhyn Gol in 1939. The vehicle was designed as a maneuverable fire unit that was unprecedented in scale—its hull alone weighted 100 tons. Only one prototype was built, without a turret and made of construction steel. Trials were discontinued due to the unreliable engine; at the end of 1944, the prototype was scrapped. The 15-cm howitzer was to be mounted on the tank after the assemble.

Developed for trench warfare. Initially, armament was to be placed in the front part of the hull and side sponsons. However, later it was decided not to add sponsons but to mount a turret. By 1943, when TOG 2* was completed and ready for trials, it was already obsolete. The vehicle never entered service.