Comparing: KV-13 vs. T-43 vs. KV-3

Development was started in the fall of 1941, under the initiative of Semyon Ginsburg. After successful trials in the fall of 1942, the development of a second prototype was begun.

Designed as a replacement for the T-34 in the spring of 1942. The T-43 was recommended for service, but all work on the project was discontinued in favor of improving the T-34. The vehicle never entered mass production.

Developed on the basis of the KV heavy tank, the vehicle initially had very few differences from the mass-produced model. It underwent field trials in January–February 1941. Eventually, several crucial changes were made to the design, greatly boosting the combat characteristics of the vehicle. By July 22, 1941, chassis and engine development was completed. According to some sources, in the fall of 1941, the vehicle was equipped with a serial KV turret and sent to the front.