Engine: Kharkiv V-2IS 520-hp four-stroke V-12 diesel
Fuel: 137 gallons internal, 30 gallons external, 110 gallons supplementary
Length: 32 feet 6 inches
Width: 10 feet 2 inches
Height: 8 feet 11 inches
Armor: 120 mm (hull front), 90 mm (hull sides) 60 mm (hull rear), 160 mm (turret front), 90 mm (turret sides), 90 mm (turret rear)
Combat weight: 46 tons
Armament: D-25T 122 mm rifled tank gun with 28 rounds of ammunition, one turret-mounted DShK 12.7 mm machine gun with 250 rounds, one coaxial DT 7.62 mm machine gun and one 7.62 mm DT gun in rear of turret (2,331 rounds total)
Speed: 23 mph (road), 12 mph (cross country)
Maximum range: 93 miles
Crew: Four

By the fall of 1942 the Red Army regarded its 47-ton KV-1 (Kliment Voroshilov) heavy tank as much of a failure as the Soviet defense commissar for whom it was named. Aside from (or perhaps due to) its thicker armor, it was slower and less reliable than the 28-ton T-34 medium tank, while carrying the same 76.2 mm main gun. Attempts to improve on its basic design included the lightened KV-13 “universal” tank (experimental only), the lightened and somewhat faster KV-1S, and the up-armed KV-85 (the latter rendered redundant when its 85 mm gun and enlarged turret proved adaptable to the T-34’s versatile chassis). After the capture of a German Tiger I in January 1943, Soviet designers set out on a major redesign to carry a 122 mm cannon in a turret. The new heavy tank that resulted was named the Iosip (Joseph) Stalin, and the first production version, the IS-2, first saw combat in April 1944. Joining it later were two turretless variants: the ISU-152 tank destroyer, packing a 152.4 mm gun, and the supplementary ISU-122 assault gun, which was simpler to mass-produce than the turreted tank.

Allotted to small, independent units similar to the German Tiger companies, the 46-ton IS-2 proved intrinsically superior to the Panther medium tank and able to hold its own against the Tiger I and II heavies in gun duels up to 3,000 feet. As with the T-34, the IS-2’s principal weakness lay in its cramped interior and limited ammunition stowage—28 rounds, compared to seventy-nine 75 mm rounds in the Panther and nearly three times as many 88 mm rounds in a Tiger. Still, the IS-2 contributed enough to be hyped as the “Victory Tank” by the Soviets and inspired a generation of improved models—the carapace-turreted IS-3 and T-10M—before Communist First Secretary Nikita Khrushchev, judging the heavy tank more expensive than it was worth, ditched the entire concept after 1960. MH