@Razor:
Conquering USA is out of question, of course.
Are you sure?
What if Japan just held its own against the UK and ANZAC, cooked china with its idle land force, and with everything else went after the US?
Japan starts with more income that the US does, and by the time the US gets it war time ecoanmy even a very conservative japan is going be making 40+ ipcs. Not to mention Japan start out with a huge military advantage over the US.
The main problem japan will face is moving its army by transport. Simply moving the required amount of force is going to take a few turns and quite alot of cash. That dosnt mean it is out of the question though.
If japan takes the alluetian islands or Hawaiian islands, they can just stockpile, infantry, tanks and transports, protected by fighters and tactical bombers. When they have enough they attack.