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 weighed 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 its assembly.
O-I
2x Kawasaki Type 98 V-12 (550)
Type 94 Mk. 4 Otsu
O-I
10 cm Cannon Type 92
O-I Kai
2x Kawasaki Type 98 V-12 (600)
Type 94 Mk. 4 Hei
15 cm Howitzer Type 96
Type 96 Mk. 4 Bo
Characteristics are specified for vehicles with crews trained to 100%.