Also known as Iósif Stalin-2 in honor of the Soviet leader with the same name. It is a Soviet heavy tank created during the Second World War that was used mainly at the end of this era.
It had poor armor in exchange for good mobility. The 37 mm anti-tank guns could put the T-26s out of action without problems if hit in the right spot.
The IS-2 focused on tilting its armor as much as possible, so that with equal weight, greater armor was achieved. The clear example is in the comparison with the KV-1, which with a similar weight was clearly worse protected than the IS-2. The interior space was reduced to the minimum possible to avoid extra weight, which compromised the maximum projectile capacity to 28, but helped to offer a smaller target to the enemy eye.
The IS-2 was born out of the need to confront the more advanced German tanks, which with their large armor caused extremely high casualties in the Soviet and Allied armies in general. The IS-2 had a revolutionary design and could measure up to the most powerful Heer tanks. Comparing it with models like the Panzer IV and earlier would not be fair because it was at least twice their weight.