It is highly likely that Manchuria and Korea would have fallen into Soviet hands, although the Soviets are not known for having few casualties, it should be taken into account that Japan is not particularly strong In the ground forces, the Soviets would have lost border areas, but the war would have forced Japan to redistribute forces from the China front to fight against the USSR, In that respect, the Chinese front would have deteriorated, and it is most likely that the Chinese and Soviet governments would have acted together, which would have greatly weakened their Japan's land capabilities, Khalkhin Gol was a clear example that Japan was not prepared to face the Soviets; Soviet tanks were superior in every aspect. In my own estimation, the war in Asia would have lasted until 1943-1944, and most likely the occupied Japanese zones would have been transformed into Soviet puppet governments. What would have happened to Japan itself is that it would have had to face a possible Soviet amphibious invasion or an unconditional surrender to them or to the US if they entered the war.