The T-10 (also known as Obiekt 730) was a Soviet heavy tank of the Cold War, the final development of the KV and IS tank series. It was accepted into production in 1952 as the IS-10 (Iosif Stalin, Russian form of Joseph Stalin), but due to the political climate in the wake of Stalin's death in 1953, it was renamed T-10.
The biggest differences from its direct ancestor, the IS-3, were a longer hull, seven pairs of road wheels instead of six, a larger turret mounting a new gun with fume extractor, an improved diesel engine, and increased armour. General performance was similar, although the T-10 could carry more ammunition.
T-10s (like the IS tanks they replaced) were deployed in independent tank regiments belonging to armies, and independent tank battalions belonging to divisions. These independent tank units could be attached to mechanized units, to support infantry operations and perform breakthroughs.
The mobile nature of armoured warfare in World War II had demonstrated the drawbacks of the slow heavy tanks. In the final push towards Berlin, mechanized divisions had become widely split up as heavy tanks lagged behind the mobile T-34s. The Soviets continued to produce heavy tanks for a few years as part of the Cold War arms race (compare the heavier U.S. M103 and British Conqueror), but the more flexible T-54 and T-62 medium tanks already had armour and armament comparable to the T-10's.
In the 1960s, the Soviets embraced the main battle tank (MBT) concept, by replacing heavy tanks with mobile medium tanks. In the late 1960s, the independent tank battalions with heavy tanks were re-equipped with the higher-technology T-64s, and later, the very fast T-80s, while regular tank and mechanized units fielded the more basic T-55s and T-72s. T-10 production was stopped in 1966, and heavy tank projects were cancelled, such as the auto-loaded, 130 mm-armed Obiekt 770.
Antitank guided missiles (ATGMs) started to be deployed widely during this period, and would become an effective replacement for the heavy tanks' long-range firepower. The Soviets made use of them first on BMP-1 infantry fighting vehicles, and later on the T-64 and other MBTs. Eventually, light, sophisticated reactive armour was used to give the MBTs a further edge in protection without slowing them down.
According to Bryan Perret, "the engagements of the Six-Day War, especially that at Rafah, merely emphasised what the Soviet Army already knew, namely that the heavy tank had had its day".
It is estimated that some 6,000 Soviet heavy tanks were built after the end of WWII, including IS-2s, IS-3s, and T-10s.