A German captured Russian KV-1S, hence the German marking on the turret side
The Russian KV-1S Tank entered production in 1942 in attempt to merge the high mobility of the lighter armoured T-34/76 and the armoured protection of the slower KV-1 tanks.
The vehicle used a reworked KV-1 hull that saw the frontal armour reduced from 90mm to 75mm (which was thicker than the T-34/76) and a new turret. The road wheels were replaced with new lighter ones as well as new tracks. This resulted in a weight reduction of 5 tonnes, giving the vehicle an increased agility and speed, hence the “S”.
The new turret was fitted with the 76mm ZIS-5 main gun. It was fitted with x3 Machine Guns (x1 in a ball mount on the front of the hull, x1 coaxial and x1 in the rear) and a spare MG was carried inside the vehicle.
The first prototype was completed in early 1942 and production (which totalled 1370) commenced in August of the same year.