the japanese had better planes which could have destroyed the T-34's and they did have armor so its not like they would be totally vulerable. Knowing the Japanese they would have found a way to beat the tanks with their infantry like suicide bomb or something, besides using their superior airforce
Is this supposed to happen after they bombed Pearl Harbor? I doubt that the Allies would've collectively abandoned the US to fight the Japanese alone, and even if they did, the USSR had plans to invade, but the US dropped the Nukes and forced a peace. As far as the eastern portion of the USSR, it was relatively empty, yes, but the amount of time and resources it would require to effectively occupy and hold that large of an area would be too much for the already spread out Japanese Army.
The Armour the Japanese had was so ridiculous that the British/US forces kept using 2 pounder armed tanks there. There were even occasions of a 76mm Sherman failing to destroy a Japanese tank because the shells went clean through a tank without causing internal damage to it's crew or components. 76mm was more used as artillery to give you an idea. Further more, most Japanese aircraft were fighter based and specificily fleet based. I don't think the Japanese would've gotten far with a war against the Soviet, probably getting ground down like the Germans. It would've been a hell of a lot harder though fighting on 2 fronts, true enough. Maybe impossible, but I'm pretty sure that the strategic reserve of Red Army and the vastly superior tanks would've been enough to hold both fronts. 2 or 3 KV-1/2 would probably be enough to stop an entire Battalion of Japanese armour.
then use it and get it destroyed. At least they didnt use it like the Germans. Send it into the middle of the ocean with only one other ship to help defend.
Attacking in China, the Pacific and Siberia would've destroyed the meagre economy of the empire. Would've ranked as one of the most stupid moves in history.
I'm sorry, but the only powers that outnumbered them were the French, USA and the Soviets, nobody else.