>>510575221Japan wanted alliance against Soviet Union in 1936 but Hitler declined. Hitler also supported Chiang Kai Shek in China (Japan was at war with China)
So Japan was forced signed non-aggression pact with the Soviet Union right before Barbarossa and turned their focus south.
When Germany attacked Soviet Union Japan remained neutral, allowed lend-lease shipping and also the info that Japan will not attack Soviet Union was leaked by Sorge. One of turning events of WW2.
Because of that the Soviet Union was able to transfer divisions from the east and hold. Soviets only declared war on Japan in summer of 1945 to grab North Korea and Kuril islands.