@taamvan
U.S. can’t if you don’t swing all the way around to India. J2 you’ve got all the Money Islands and J3 you can take Malaya, J4 you head back to Philippines or off coast of FiC if you splurged for a naval base (I don’t). Japan’s fleet is strong enough to cover 2 transports and sz6 for sure for a turn or 2. Maybe 3 transport zones if US1 buys for Atlantic.
So for buys to keep US off Japan’s back…(ipcs based off a balanced Mod game)
J1 (26ipcs) 1 mIC and 2 transports
J2 (43ipcs) 1 MIC (FiC) and 1 carrier for sz 6, then rest on mech/tank for mainland
J3 (58ipcs) 1 or 2 carriers for sz 6 and inf/art for FiC and mech/tank for Northern mIC
and so on… every turn I check the battle math of whether the U.S. forces could hit sz6 and add a carrier, land 1-2 more planes on it… by J4 I usually have 2 or 3 carriers with my Southern fleet, and 3 or 4 carriers in sz 6 if the U.S. is buying for Pacific side. After J4 I usually start adding destroyers and subs to my fleet.
Its also a useful strategy because a bored U.S. player might hit the Caroline Islands… every single Japanese plane can reach from Japan, FiC, and your ships (and land on Palau or carriers).