It’s tricky, since a good Japan player will whomp all over the Pacific anyways. What you need to do is rob Germany of Africa and place the IC at a spot that can’t easily be taken out.
The optimal place to put the IC is actually Egypt as it properly reinforces Russia, puts pressure on the Med, makes a giant choke-point for Africa. The U.K. is now in range of Europe on both sides, blocks the Suez forever, and can send units to Russia easier, because they don’t have to be stacked on defense(can’t hold India forever anyways).
But you will need U.S. support, so you might have to wait until turn 2 to place it unless the German med fleet is badly beaten. Russia can also of course send air cover for it if you decide to build it on turn 1. If the U.S. player sends their bomber there as well, they can later on do effortless strategic bombing of Italy as well and be well within range of Europe. It’s also the optimal place to use U.S. and U.K. forces to do the famous 1-2-3 punch vs Eastern Europe. Two turns later, U.S. forces will have a large stack of units there and it’s never being taken down.
With that in place, the U.S. job is much easier and they can concentrate solely upon Japan and Germany proper. Forcing Germany to actually fight a war in/reinforce the Med. is all you need to do to cripple its focus on Russia.
Note - the counter to the U.S. and to divert its attention is to actually take Hawaii with troops(Central America is now in range - and the U.S. has to not leave any openings). This game is highly dependent upon dividing your enemy’s focus to multiple fronts. If Japan doesn’t do at least this and the U.S. can focus entirely upon Europe, it’s over for the Axis.