The JS tanks were named after Joseph Stalin. The JS-2 had a 122mm D-25T main gun and 6 road wheels to improve soft ground track performance. In 1944 new specifications included new armour tempering, a 60-degree glacis replaced the 30-degree and the driver’s front hatch was removed. Also a relocated wider porthole, improved mantlet, increased lower hull side armor and a new periscope sight. The commander’s cupola moved to the left and a 12.7mm anti-aircraft machine gun attached. In 1944 2,250 JS-2’s were produced and no further improvements were made until 1954.
During the Battle for Berlin that took place from April 16, 1945 until May 2, 1945 a large number of JS-2 (IS-2) heavy tanks were used to spearhead the assault. They were used to eliminate or flush out German forces by destroy entire buildings using their HE rounds. Most JS-2s were assigned to groups of 5 along with a company of infantry comprised of flame throwers and sappers. About sixty seven JS-2s were lost during the battle, most victims of “Faustniks (panzerfausts)”.