I’ve not been able to playtest this, but my idea is to pull off the coasts starting on turn 1 (July 36) to avoid Japanese naval bombards. Also, don’t attack the Communists or Warlords- just lay low until the Japanese come. When they do, defend Yunnan and Xibei San Ma at all costs- Yunnan for obvious reasons and Xibei San Ma because its size means that you can funnel units from the north to the south safely and vice versa. If the Japanese didn’t take Guangxi on their first turn at war, then build it up. Starting July of 38 pick up at least one fighter in Lend Lease, plus the Flying Tigers. Refrain from attacking the Japanese unless you’ve got a huge numerical superiority, because of the attack weakness. The trick is, Japan needs your coastline to have enough income to fight the US and UK. If you can keep an army intact in your interior until they go to war with the West, then you can overextend them by forcing them to spend resources defending that $. Don’t worry too much about the civil war starting back up- you’ll be able to get plenty of aid.
Same goes for the Communists, except everything is on a smaller scale.