The Soviet heavy tanks would face the staunchest test later in the war: the German invasion of the Soviet Union, Operation Barbarossa, which began in June 1941.
By this stage in the conflict, Germany had overwhelmed nations of Europe in short order with devastating rushes, its deadly tanks at the fore. Adolf Hitler and his generals believed that victory here could be achieved by that October. However, this didn’t take into account formidable Soviet tanks like the KV-1.
The KV-1 had been developed the year before, after a Main Military Council meeting of 1938. Here, the Soviets planned a heavy tank more powerful yet more practical than any in their roster, building upon the T-28 and foregoing the extra guns they had originally planned to add. The KV-1 that resulted was a vehicle to behold indeed.
The KV-1 was equipped with a 76 mm cannon that weighed a mighty 47.5 tons, and its armor was 75 mm thick. Its German opposition at the time struggled against it. In “When Titans Clash,” David M. Glantz notes that Mark III and Mark IV tanks wielded 50mm and 75mm guns in 1941, and that “neither German weapon could penetrate the thick frontal armor of the T-34 medium tanks and KV-1 heavy tanks.” The latter took this concept to the extremes, and its gun was strong enough to destroy any opposing armor in return.
