While developing new single-turreted tanks more closely based on the Renault FT, many countries, including Japan, also experimented with the possibility of multi-turreted designs.

[3] The Imperial Japanese Army made the decision to develop heavy combat vehicles, which was prompted by the increasing threat posed by the Soviet Union, a potential enemy of Japan in East Asia.

[5] In 1931, the Osaka Arsenal produced a prototype heavy tank that was designated as the Type 91 (Imperial year 2591).

[2] It had seventeen road wheels on each side, which were supported by a "two-stage leaf spring suspension system".

[6] Although the tank underwent numerous field tests, it was considered to be underpowered, under-armed and lacked sufficient armour.

Each proved to be a complicated, cumbersome design with poor mobility and a lower top speed than was desired.