I think that if your going to win with Japan, do it either by capturing India, or victory points. Both of which I’ve seen done. Here’s my views on the following ways of Japan achieving victory. If Japan focuses on….
Australia
Problems with Invading Australia
America can fly planes down for support by the time Japan has assaulted Northern Australia
Australia is a richer nation then India, raking in 20 IPCS as opposed to India’s 15
If you focus on taking down Austrlian IPCS (eg: invading java, and sumatra) in the islands, that by the time you reach New south wales, they have to much defense.
Harder to get air support for your attack on New South Wales
Good things about Invading Australia
Going for Australia might be a good idea, only if the British player is anticipating an Indo Swing, and gives all the convoy money to India. Forcing Australia to have less money.
If the British player makes poor purchases for Australia (eg: subs, and not any land defense units)
India
Problems with Invading India
Hard to get air support for assault on India, unless you capture Shan State or Yunnan by J2 or J3.
Chinese forces, seeing a possible Japanese invasion of India, may send infantry to help, or invade your Korean, and Manchurian forces. Not a significant problem, but one to consider.
Good things about Invading India
You can mass a HUGE fleet in Sumatra, by J2. Composed of many destroyes, battleships (which are good for shore amphibious assaults), and 10-12 transports full of infantry, artillery, tanks.
If by J2 you can capture Shan State, J3 you can land your planes there, and the planes will be in range of attacking the Indian Capital on J4.
Even if India moves his forces up to Burma and trys to attack Shan State’s Japanese men, which they wont because they wont have enough men to defend India capital, the Burma forces will treat back to the captial because if they dont the ships and transports sitting in Sumatra sea zone will take the unguarded captial on J3.
Farthest Capital away from USA, hard for USA to send fighter support
If you go after India, you might be able to take China as well, not neccessary, but fun taking 2 capitals.
Victory Points
Problems with winning by Victory Points
Can make the game alot longer
If you don’t pressure India or Australia, they will attack your helpless stray ships
America can moblize an attacking force to invade Japan Capital
Good things about winning by Victory Points
If you can foritfy Java, Sumatra, Malaya, Borneo, with infantry and fighters, it will be difficult to invade them (all these islands and coastline territory have a combines IPC net of 14 IPC
If you can keep a good supply line of transports going from Japan to the mainland (French Indo China, Siam) you can delay any India mainland attacks
If you rake in 40 IPC a turn, and are holding that amount for 5 turns, you are almost guarenteed a victory