KV-1

The KV-1 tank was a heavy tank design trialled in the Soviet-Finnish Winter War. Performing the best out of all prototypes, the KV-1 entered mass production and became, at the time, the most powerful tank in the world. Armed with a 76mm gun and protected with thick armour, the KV-1 and KV-2 were able to resist the sudden German assaults with almost comical ease. The light anti-tank guns of Germany were unable to penetrate the armour, at best damaging the tracks and other external components. A single KV-1 could defend a spot for days without support by virtue of its implacability, and only extremely lucky shots, infantry-placed explosives and hastily redeployed 88mm anti-aircraft guns could neutralise them.

As the war progressed, the limitations of the heavy, obsolete chassis became apparent as German anti-tank capability increased. The T-34 could mount equal or greater firepower while being faster, cheaper and more reliable, and the new IS series were superior in the heavy tank role. Attempts were made to modernise the hull, but proved fruitless, with all efforts focused on the T-34 and IS designs.