The ST-A1 was Japan's first indigenous tank design after the war, being the first prototype towards the later Type 61 MBT. It was mainly based on the M46 Patton, carrying the 90 mm M3 cannon capable of firing HEAT-FS to defeat contemporary Soviet armour.

It was introduced along with the initial Japanese Ground Forces tree in Update 1.65 "Way of the Samurai". The ST-A1, similar to most Japanese tanks, is lightly armoured. Combined with the tight placement of crew, modules, and ammo, the ST-A1 is easily taken out in a single shot. The ST-A1 can serve as a sniper or flanker (although it does not have the best speed), however, full utilization of the terrain is essential for survival - due to its powerful gun and low profile, the tank is able to fire off long-range shots without exposing itself. The excellent reverse speed should also be taken advantage of to quickly retreat into cover.