Yeah JWWII is right on, you should read the posts from NCS, they have a lot of good insight on how to play well. I learned a lot on how to play Japan just by reading his posts (I always do the 3 trannies build on J1 now 🙂 ).
NCS, regarding your US moves, I think you just didn’t stick to your initial decision of attacking Japan with the US. I think you could have done great by pushing harder in the Pacific. The Japan fleet was very weak, and a little US fleet could have easily contested the islands. Just my toughts.