Some of the attacks you have listed there are not enough overkill for me and in many cases you wont have much follow up on them in China.
For example:
1 Bomber from Japan destroys the Hawaiian transport, and with the assistance of the Japan airbase, can land on the Marshall Islands.
This isnt even possible with the US LBA at Pearl. They will Scramble the Fighter and the TAC and likely trade out well with your bomber.
o 1 Fighter from Formosa, 1 Bomber from Manchuria, and 1 Bomber from Japan wipe out the British Battleship and 2 Transports in SZ 37 around Malay. The Fighter must land in Siam, while the 3 Bombers have enough movement to land in Kwangsi. If you are uncomfortable with the odds, the Bomber in Kiangsu may also participate.
Quite possible, but also potentially expensive. Sure you are killing 20 IPCs of Brit BB, but you are risking 10 IPCs of Japanese air. If you wait and go later on you can often kill the Brit navy for almost zero cost by taking hits on BBs and/or Subs.
o 3 Infantry and 1 Artillery from Kwangsi move into Yunnan. 1 Fighter, 1 Tactical Bomber, and 1 Bomber (if not used against the British Battleship) fly to Yunnan, to land in Kwangsi after the fight.
You’ll obviously win here, but you are unlikely to kill them all on the first round. This means more potential losses of valuable ground troops in China. In addition, you will have less to hold against the all-important Chinese counter-attack.
1 Battleship and 1 Destroyer from the Caroline Islands moves to Sydney and destroys the Australian Destroyer and Transport.
If the Aussie hits, you’ll likely lose both to the RNZAF. If I’m the Allies, that’s a trade I’ll GLADLY make. Even if the DD doesnt hit in the initial battle they might still counter-attack and win (4x3 vs a 4 and a 2 with 3 hits). Japan cannot afford to lose her early superiority piecemeal.
The 2 Transports from Japan move 2 Infantry, 1 Tank, and 1 Artillery into the Philippines. The Fighter and Tactical Bomber from SZ 35 also move in for the island attack.
Again, a pretty risky attack, not in terms of winning, but in terms of what you might lose in the process. That fight is far from overkill vs 2x2, 1x1, and 1x4. A few flukey dice and you could lose most of your ground pounders which will set you back quite a bit.
2 Infantry from Kiangsi attack Kwangtung. Then several Fighters and Tacs fly in from Manchuria and Japan to help.
Ditto. Again, a winning odds battle, but still quite possible to take 2 hits and lose the ground forces. At the very least you have good odds of losing 1 Inf which will not easily be replaced on the continent.
IMO, while none of these attacks are ‘bad’, you are very vulnerable to a few strings of luck leaving you VERY weak on the ground. You have no follow-up to these attacks. In China, with no factory and no additional TRs, you risk becoming bogged down, especially with the Brits free to counter-attack into Yunnan. I consider Yunnan to be CRITICAL to the Japanese victory in Asia and you will need a lot of luck to keep it closed down.
Put it this way, if I HAD to attack on J1, I would likely follow something very similar to what you have here. It is a solid plan for a J1 attack. But IMO leaving the Allies alone for a few turns doesnt really alter the basic equation that Japan has a FAR superior military at the point of attack. What waiting does is allow Japan to position for less battles where the outcome can be remotely in doubt. The goal is to suffer minimal casualties on the turn of attack as well as have follow-up forces already headed into the battle. The idea is to have a more powerful sustained attack rather than a flash in the pan attempt at big success on turn 1.