The KV-1 (ZiS-5) is a Soviet heavy tank. It was introduced during the Closed Beta Test for Ground Forces before Update 1.41. This KV-1 introduces a new armament, the ZiS-5, that has a much stronger punch than the L-11 from its predecessor while retaining the same armour.

This tank is very similar to its predecessors, but mounts the same gun of the T-34 (1942) sharing its ability to fire APCR shells. The player should feel at home once going through the KV-1 (L-11), and while not as fast as the KV-1S, it maintains more armour all-around. The gun may be lacking on penetration unless using APCR shells, its velocity is poor (makes it harder to aim in Realistic Battles), but will do plenty of damage once penetrated and reloads quite quickly. The armour is outstanding when angled. With extra 25 mm spaced armour at the front of the hull results in a total of over 100 mm of armour. The tank can take a lot of damage from lower ranks and still survive the battle. The turret remains vulnerable, however, but the turret ring is reinforced, which means that it's harder to jam the turret.