It seems I am the only one here who has a different opinion than everybody else :-D the thing with japan is that if you have good navy positioning, you’re starting navy should be enough to hold off the us for a couple of turns without you having to buy anything. During these precious turns, grab as much money as you can in Asia, and then use this income to have an arms race with the US.
If you start purchasing navy right off the bat, the India will wipe you off off Asia. This doesn’t even take into account russian pressure from the north. So in my opinion, only make navy buys when you have the income to afford it.
(P.S If you dont do pearl harbor, the us can pretty much put pressure on you without buying anything at all, let alone going 100% pacific.