I personally played this game several times, alone and with friens
My consideration is that 6 or 7/10 Japan can win.
Take most advantage of the J1 special rule.
Take most of the money island and sink all the ship you can; british too; focus on allies transport too.
Move all in to India; while pushing China west.
Japan can win if they get India within J4 / J5.
The longer the game, the more the pain, because US pressure will become too hard to hold