The development of the KV-1 heavy tank began on February 1, 1939 at the plant in Kirov under the leadership of N.F. Shashmurin. The same SMK tank was taken as a basis. Although the KV was designed on the basis of the QMS, it had one huge difference - one tower. This made it possible to make the tank smaller, which had a positive effect on running and armored characteristics, because it was possible to install more durable armored plates on the tank without prejudice to its cross-country ability.