To add my two cents -
I’d define what you mean by win.
In this case, winning would mean holding on while Axis forces in Europe took the game. So… you have to magnify your strengths.
What is your main strength as Japan? Air power. What is the best way to harness air power with Japan? Carriers. Carriers are a force multiplier - a Carrier group will often allow you to bring double the aircraft on offense, if you position yourself well. On defense, they speak for themselves.
Carrier purchases are also about timing. The further the US gets from their supply line, the more they’re getting into your area of resupply. Nothing is more frustrating to the US player than sizing up your fleet, moving in and putting Japan in a compromised position, and watching Japan purchase 2 Carriers on the same turn… for 32 IPCs, your navy just gained eight more hits to kill it.
Also, position yourself defensively in kamikaze zones, to amplify your defense. And if you have to use them in a major battle, I’d suggest choosing six different one-hit units (destroyers and cruisers), so that you don’t waste any good rolls, and remove offense off the board immediately.