The IS-3 is the third variant of the IS heavy tank family. The IS-3 featured a revolutionary front hull and turret design that would become the trademark of all postwar Soviet tanks until this day. Since the IS-3 differed from earlier designs in many ways, a thorough retooling was required for the first time. This took time, and the first three IS-3s rolled out of the factory in May 1945, ready to go into service in Germany under an independent Guards Battalion. When they arrived, though, the peace treaty had already been signed. Many more IS-3s were ready by the time of the August invasion of Manchuria, but there is little indication that they took part in these events.