After Object 223 was finalised as the design for the KV-3, the 107mm ZiS-6 cannon was made a requirement for the main weapon of a new super-heavy tank to be produced as the KV-4. Twenty-seven different designs were submitted for the project, some very similar to each other, while others were radically different from any tank yet built, Soviet or otherwise. Among the designers to submit a proposal for the KV-4 project was Nikolai Fëdorovich Shashmurin, who had already worked on both the SMK and KV-1. Shashmurin showed his apparent preference for the SMK in his KV-4 design, Object 901, which was the largest and heaviest design submitted, with nine pairs of road wheels supporting 110 tonnes. According to Shashmurin’s own memoirs, his design was ultimately selected for the KV-4 project, in spite of other designers deriding it as a glorified self-propelled gun. However, regardless of which design was selected, the KV-4 project was cancelled when the Wehrmacht attacked Leningrad, and no prototype was ever constructed.
Unknown № 1
Project Dukhov (the KV-4 as it currently appears in World of Tanks)
Project Kuzmin, et al (known as KTTS in World of Tanks)
Project Strukov (the KV-4 as it used to appear in World of Tanks)