Am I imagining things or did you leave both India and SFE unguarded
This looks like a KJF strategy, with the US pumping 24 IPCs min per turn to the effort.
The Japanese advantage to exploit here is that the Allied forces on Sinkaing are from all 3 players. Together they are strong on defense, but on offense they stink because they have to attack separately.
Japan needs to play conservatively, and Germany needs to press Russia hard. Sending the Jap airforce to Europe to back German advances and sink Allied ships might be a good option.
I would build a JAP IC in KWA on turn 1 to pump out 3 ARM per turn. With 2-4 inf from the mainland a turn a steady pipeline can be aimed at Sinkaing.
China will be taken on turn 1 to Kill the US Ftr (Always!)
Other infantry will pressure Russia towards Yakut.
JAP and Germany will strat bomb the IC in SIN forcing the US player to suck up the damage or waste a build slot on an AA gun.
Early attacks on Alaska and German forces pushing from Egypt through Persia for a 1 to punch on Sinkaing will prove beneficial.
Sorry for the rambling. Glad to be bac after so long and see the site is still going strong.