The 1st prototype was 2 tanks (STB1, STB2) built.
STB1 built first carried a wireless remote controller
AA machine gun. Notice to a difference of turret shape with manufacturing
type. STB1 was started a mobility test in June, 1969. A lot of
practical use tests were done until September, 1970. This STB1
was introduced toward the press in October, 1970. After that,
This tank participated in a JGSDF parade, and it was shown to
STB2 was started a mobility test in July, 1969.
A lot of practical use tests were done until February, 1971.
This tank was not shown to general citizens.