The IS-2 (, sometimes

romanized In linguistics, romanization is the conversion of text from a different writing system to the Roman (Latin) script, or a system for doing so. Methods of romanization include transliteration, for representing written text, and transcription, ...

as JS-2The series name is an abbreviation of the name

Joseph Stalin Joseph Vissarionovich Stalin (born Dzhugashvili; 5 March 1953) was a Soviet politician and revolutionary who led the Soviet Union from 1924 until Death and state funeral of Joseph Stalin, his death in 1953. He held power as General Secret ...

(); IS-2 is a direct

transliteration Transliteration is a type of conversion of a text from one script to another that involves swapping letters (thus '' trans-'' + '' liter-'') in predictable ways, such as Greek → and → the digraph , Cyrillic → , Armenian → or L ...

of the Russian abbreviation, while JS-2 is an abbreviation of the English or German form of Stalin's name.) is a

Soviet The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...

heavy tank A heavy tank is a tank classification produced from World War I to the end of the Cold War. These tanks generally sacrificed mobility and maneuverability for better armour protection and equal or greater firepower than tanks of lighter classes. ...

, the second of the IS tank series named after the Soviet leader

. It was developed and saw combat during

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

and saw service in other Soviet allied countries after the war.

Design and production

Object 237 KV-85 and IS-85/IS-1

The

KV-1 The Kliment Voroshilov (KV; ) tanks are a series of Soviet heavy tanks named after the Soviet defence commissar and politician Kliment Voroshilov who operated with the Red Army during World War II. The KV tanks were known for their heavy armour ...

was criticized by its crews for its poor mobility and the lack of a larger caliber gun than the

T-34 The T-34 is a Soviet medium tank from World War II. When introduced, its 76.2 mm (3 in) tank gun was more powerful than many of its contemporaries, and its 60-degree sloped armour provided good protection against Anti-tank warfare, ...

medium tank. It was much more expensive than the T-34, without having greater combat performance. Moscow ordered some KV-1 assembly lines to shift to T-34 production, leading to fears that KV-1 production would be halted, and the SKB-2 design bureau, led by Kotin, closed. In 1942, this problem was partially addressed by the KV-1S tank, which had thinner armor than the original, making it lighter and faster. It was competitive with the T-34 but at the cost of no longer having the heavier armor. Production of the KV-1S was gradually replaced by the

SU-152 The SU-152 () is a Soviet self-propelled heavy howitzer used during World War II. It mounted a 152 mm gun-howitzer on the chassis of a KV-1S heavy tank. Later production used an IS tank chassis and was re-designated ISU-152. Because of it ...

and ended in April 1943. The capture of a German

Tiger The tiger (''Panthera tigris'') is a large Felidae, cat and a member of the genus ''Panthera'' native to Asia. It has a powerful, muscular body with a large head and paws, a long tail and orange fur with black, mostly vertical stripes. It is ...

tank in January 1943 led to a decision to develop a new heavy tank, which was given the codename Object 237. Before Object 237 had time to mature, intense tank fighting in the summer of 1943 demanded a response. Dukhov's team was instructed to create a

stopgap {{Short pages monitor