OOB setup. The key to this strategy is deception, luck, and adhering to the noncombat movements suggested.
J1. Buy 3 trans. and 1 art.
Noncombat, take AA and Inf from Carolines and leave them on an unguarded tran within easy striking distance of the UK or ANZAC. Divide your fleet into 2 halves. Position 1 in SZ 33 and the other in SZ 20 (make sure to leave the unguarded tran out of either group, and that the rest of the trans. end up in SZ 20) . Move all Manchurian troops into Jehol, and make sure that the art originally in Jehol stays in Jehol. Keep carriers fully loaded, and position all other planes in Kiangsi. Leave 1 bomber in Siam by itself. The goal of this is to coax the UK or ANZAC into attacking you in their first turn. If they don’t then abandon this strategy, but if they do, then read on.
J2. Buy planes.
Combat, take the 3 trans. from SZ 6 and invade British Columbia with 3 inf and 3 art. This will not drag U.S. into war since UK or ANZAC attacked you first.
Noncombat, take the 2 trans. from SZ 20 and use them to move 2 art. to Japan. Rendezvous the entire Japanese navy and air force in Japan.
J3. Buy bombers.
Noncombat, use trans. from Japan to move 2 inf and 2 art to British Columbia. Move the rest of the Japanese fleet to SZ 1 and move all planes to British Columbia.
J4. Buy fits the situation.
Combat, attack U.S. with 5 inf 5 art plus ALL of your planes including the bombers you purchased last turn (these will land in British Columbia)
Good luck with this! This strategy certainly has its faults, I designed it merely to provide the Japanese player with the highest chance of capturing the U.S. It will only work properly if UK or ANZAC attack Japan on the first turn. If you find ways to tweak and improve it, feel free to do so. Criticism is welcome so long as it’s all delivered in a respectful way. I’m only 16, I don’t have time to waste arguing on the internet. A tip for this strategy is good acting. Make the allied player believe that it was a genuine mistake on your part to leave an unguarded bomber and fully loaded transport.