In the 1930s, Stalin was modernising Russia. He had claimed that Russia was “50 to 100 years” behind the West, and that without catching up in 10 years, Russia would be overrun. Though this was largely political spin to justify his wide reaching plans, it also implies that possible conflict was on his mind.
However, when war broke out with Germany, Stalin was so surprised that he vanished from public view for a fortnight; some historians claim that he had a mental breakdown from the shock at what had happened. The army was unprepared, their equipment second rate compared to the German tanks and planes, their tactics were outclassed and the officers remaining after the Purges lacked experience. The revision slides below help to answer why this was possible following Stalin’s modernising plans.