On the 7th of April 1941 the Russian army set out its revised requirements for the KV-3 and the requirements for two new Heavy Break through tanks, the The Russian KV-4 Heavy Tank (super Heavy) & KV-5.

The design process for the KV-4 was some what disorganised when compared to the KV-3, as the  Kirov Plant did not have experience in the area of super heavy tanks, so its entire engineer staff were allowed to submit designs to meet the requirements of the vehicle, which was too have a lengthened hull, be armed with the ZIS-6 107mm main gun and its armour was to be 125 to 130mm thick. Of the many designs submitted by the staff, no clear design was selected and the project died.