In the early 1960s, Mitsubishi started development of a new tank that complied with government requirements for armament and defense. The first two prototypes of the STB-1 were manufactured in September 1969 for trials. In 1970 the prototypes were shown to journalists and participated in a military parade.
The technical characteristics shown are for the Siege mode
Characteristics are specified for a vehicle with crew members trained to 100%.