If the US keeps investing heavily into the Pacific, Japan has two choices:
Get all the IPC you can early (per Cow’s strategy) or…
Play turtle in SZ6 and take the long road into Moscow from the East which generally requires an IC on Manchuria/Korea or both. In particular you let the US spend its IPC to get a fleet to take out yours in SZ6 and utilize Kamikaze to disable CV so the US aircraft cannot land and have to splash.
You have opportunities to get the Japanese Air Force into Europe as early as J4 (J1 Chahar, J2 Suiyuyan, J3 place AB on Suiy, J4 fly as far as Leningrad (Kansu - Novo - Volo - Arch - Novg).
With the AB at Nov, J5 will be a full pummel of Moscow’s MajorIC allowing German Air Force to assist in the advance of its ground units towards Moscow. You can also open up doors for the Germans to blitz by trading Jap aircraft to open up spaces the Russians thought they had defended. J6 is a suicide of Aircraft against Moscow to weaken the garrison on Moscow for a G7 attack there.
You can also decide to rush for an India Crush and instead of turning to face the Allied fleet Post India Crush, race instead towards the Med to assist Italy in taking and holding Egypt with your fleet. Building IC in Kwang and FIC assist in getting more units on the board once you sacrifice SZ6 to the US. Realize you can stop the US from loading units onto a TT from an IC in Korea every round by just buying a DD in SZ6.
I played a version of Cow’s J1 attack where I had the US fleet chase me around the Pacific - sent a TT with a small fleet of CV, CR, DD and TT (with 2 Inf) from SZ6 to Caroline to Line and was in position to land Jap units at the Panama Canal. I ended up taking NZ instead of Pamana due to a 10 SS purchase by the US when I was at Line Islands. The US/Anzac eventually chased down and sunk that fleet, but that occurred by the time I got it all the way back to Java and had crushed India - sometime around round 6 or 7.
Just remember, even if Japan loses Tokyo, the Axis still needs to lose Berlin for the Allies to claim victory. There are plenty of possibilities for Japan to assist in the European theater for the Axis win in Europe.
As for the Pacific - I have played Japan the last… 6 or so games and I have yet to win in the Pacific. The closest I came was with Cow’s J1 attack but I was short 1 TT to take Hawaii which was unguarded.