Soviet-designed T-54 tanks were introduced in 1949. The family includes the T-55 evolutionary variant, as well as Chinese derivatives such as the Type 59. It was an extremely successful design, and perhaps the most widely used in the world after the Second World War.
Typical T-54's were armed with a 100mm rifled gun, as well as secondary machine guns. T-55 improvements included two-axis stabilization of the main gun, although the tank still had to stop to fire accurately.