>>/21687/
> how so?
Because main reason that they didn't attack was their defeat from Soviet army in limited conflicts of 1939. Placement of their forces didn't allow USSR to withdraw army from Far East, but attack, even not successful as blitzkrieg, could do much better effect in worst (for USSR) years of war.
> Even if germans win, japanese would gain too little in peace table compared to germans. Risk is too big and gain is too little.
And if Germans lose, Japan also lose much. Sometimes you need to do something risky and unsuccessful to win in big picture. USSR army also wasn't really so powerful and strong until late part of war, and Japanese forces aren't that bad.
Maybe with success at Far East and Europe with combined actions of Germany and Japan would stop USA from joining the war (especially without Pearl Harbor), giving time for Axis to consolidate more forces and pacify occupied lands.
Although all these alternative theories are very weak, because sometimes even small differences may change history much.