7. Germany Had Coordinated With Japan On The Invasion Of The Soviet Union
Germany made a serious mistake by invading the Soviet Union on its own when it could have coordinated with Japan and forced the Soviets to fight on two fronts. One reason why the Soviet winter counteroffensive succeeded just a few kilometers from Moscow was that the Soviets were capable of reinforcing their military with well-equipped and well-trained divisions from Siberia.
These fresh troops stopped and repelled the winter-stricken German soldiers. If Hitler had coordinated with Japan during the Soviet campaign, this would have been the most likely scenario: As German soldiers advanced from the west, Japan would have invaded the Soviet Union from the east.
Japan would have pinned down the military reinforcements that rescued the Soviets from the brink of defeat at the hands of their German invaders. Moreover, the sheer size of the Soviet Union allowed it to trade space for time. If Germany and Japan had invaded the Soviet Union simultaneously, the Soviets wouldn’t have had that luxury.