Hi randell765:
Honestly I've just been following a modified version of Japan's real strategy for expansion.
A few tips (this is assuming playing the AI):
1) Before you attack the WAllies, try not to ever move a Fleet more than 1 space/turn. You have time to get everything in place...no need to burn precious supplies for nothing.
2) Move the Carriers slowly to off the coast of China, and all your other air units into China. Take the coastal areas ASAP and repair the resources. Use your Air power every turn to 'cull the herds' of Chinese troops massing on the border. If you dont, they will eventually mass up and attack at the worst times costing you supplies and the resources along the coast. You'll lose a plane here and there, but what they lose takes FOREVER to rebuild.
3) Research. You have to prioritize here. I only get (in order) CAG Evasion, CAG Torpedo, Light Fleet ASW, CAG A-A. Thats all you really need to defeat the early Allied fleets AND keep your Transport Fleets alive (critical). Later in the game, you need to research up the Infantry attack and evasion or eventually you cant even take India or Australia from the Allied Infantry. Other techs might become necessary, but for the early game, just go with those 4. You should have them all before W'42.
4) Early builds: I concentrate on Supply, the above research, a replacement CAG, 2-3 Transports, and a few Militia/Infantry as time/population permits. Supply and Transports are key to taking and repairing the critical early resources.
5) Slowly empty the Garrisons on most of the Islands into China. You can use the Militia for occupation freeing up you Infantry for the attacks. The Artillery should definately be used at the front.
6) Make sure you have built up 120 or so supplies earmarked for your attacks and repairing of resources
7) Kick off the War:
In W'42, I move the CVs to Pearl and smack the US Fleet. If you have your research done (and the patch!), you should cripple/kill 4 ships and take no losses. Then move back towards Rabaul and support the attacks in the South Pacific.
By this time all of your BBs should be in position to exterminate all the Allied Light Fleets in the South Pacific (using only 1 supply each). Have your subs pick off Transports and move back near Australia out of harm's way. They'll eventually be hunted down and killed, but they can kill a handful of Transports before they go down. I never build more Subs because the Allies are concentrating on ASW against the UBoats anyways, so your subs will just be massacred.
After crushing their South Pacific Fleet and hitting Pearl, the Allies wont have much to oppose you for the first few turns. Use that time to move into Siam and towards India (you need Transports over there to supply the effort as the rail lines dont run that way). Spread out and take some of the Islands in the South Pacific once you secure the actual resource islands. The island bases should house you Betty bombers to use on Allied Transport and sever the link to Australia.
From there, its just a matter of seeing what is going on and reacting. You can take Australia or threaten Russia or move into India if the Brits dont reinforce. I've noticed that if you kill enough transports and continually batter the US carriers and BBs that come out to play, they will eventually cede most of the Pacific to you (except for sub activity). This is bad news for Germany so you have to be prepared to put the pressure on in Russia or India. I'm in '45 now in my game and my Factories are humming along at 27 while the Wallies are only at 54. This is TERRIBLE for them at this stage, but I'm sitting on Australia, India, half of Africa, and most of the Mid-east. I've been into the Russia homeland long enough to wreck the resources. Russia only has 16 working Factories (although Germany has been reduced to small fortress state by the Wallies).
A note on ASW: Keep a few Light Fleets near Japan and to the North. The Wallied subs often come by that route as it bypasses my island bases. By escorting the few Transports around Japan and engaging in aggressive ASW, I've kept Transport losses to a minimum. Never skimp on ASW. Burn as much fuel as you need to kill off the subs. Never leave one alive for more than one attack. If they go ballistic with the number of Subs, build another Light Fleet or two.
A note on Transports: You can never have too many...ever. They are your life-line to your resources, your supply routes for your fleets, and your threats into Australia and India/Mid east. If you run out of Transports, you are out of luck. I always try to keep at least one in the queue. If the Allies are killing some, you must replace the losses ASAP. Once the Transports start to go down, your econ goes into a tail-spin and you'll never get out.
A note on Supplies: Early in the game, you have to pinch every penny. The only supplies you should be using are the 10 or so to air raid the Chinese Troops and the 1/fleet to move 1 sea zone at a time. If you manage your research properly and dont get too unlucky in China, you have enough supplies to use your fleet to get the job done early in the war. After you have 'fed' all the Factories you own, you should be able to keep ahead of the Supply problem. Indeed, I've found that the bottleneck from mid 42 on is often lack of Transport capacity to get the supplies where they are needed rather than lack of supplies in general. On that note, Always build supplies in Manchuria and in captured Chinese factories. The less supplies you actually have to SHIP to the main land the better!
A note on Carriers: With the above research, your Carriers should be superior for most of the early war. The Wallies just have too many other priorities to worry about cranking out Carrier Aircraft to match yours. If they do so, you'll be in for a hurt, but Germany should be having a field day. Be happy you have a teammate at that point.
Until the US gets better Carrier aircraft, you can smash their Fleets with relative impunity. Note that if the US researched Battleship AA to 5, all bets are off (I consider this a balance screw in the game, as I believe a Human player can do so before the war and ignore carriers and beat you with just BBs/CAs). Barring that, dont move your CVs around too much if you can avoid it. Use land-based air to add to the carnage.
I have now successfully managed to take over the Pacific in three games now using the above strategy. I realize that vs a Human player, things would be considerably different, but I take solace in the fact that my German Ally would probably be bringing more pressure too!
Good luck. Let me know if any of this helps you out!