What you can get away with as Japan has a lot to do with what Germany is doing. That said, there’s a few major avenues of attack:
1) Kill India by round 3 - if you wait after that, you’ll never get it, it’s too heavily entrenched.
2) Major complex in Korea, start blitzing Mech/Armor into Russia to sap them of strength and allow an easier target for Germany - course this means you give up much of your naval and air dominance, you should still be able to hold out until round 9 or 10 with what you have and a few more destroyers.
3) Drive through China - biggest waste of time and resources if you ask me. I say hold the VCs and Manchuria and let the Chinamen have their territories.
4) Go for Hawaii/New South Wales and hope to buy time.
The only way I see for Japan to actually WIN is to take India on round 3, maybe round 4. Otherwise, you’ll never get the VC you need to win.