@ghr2:
I guess it really depends on how strong they of an India they want to deal with and if they want to pressure russia from the east. It also depends on the japanese buys and naval positioning for the first 2-3 rounds.
I think there is no choice in the north to always keep enough ground there that you can wipe off any Amur stack if he dares to come in there.
regarding the buys there is imo usually not too much of a choice for Japan as you need to my mostly transports and usually 1 IC. I’d say only a small fraction of the JP money can be spend variable on e.g. Naval in case US invests a lot in the Pacfic or rather into e.g. a bomber if US invests more in the Atlantic.
If The US and anzac link up at queensland round 2 or 3, it becomes tricky for japan to keep the money islands secure, even more tricky to protect all of the transports.
The best way to do a J3 or J4, in my eyes, is to try to make it look like you can declare war at any time so the allies don’t prepare for it correctly.
I have to say I do not exactly understand that so far but maybe I am biased as in my current game my opponent threw ALL US money in the Pacific neglecting Europe.
To my understanding it should be the goal of US to take Caroline and build a sustainable outpost there. This is imo possible with the help of Anzac. After DOW JP usually must clear Caroline. US takes, Anzac secures with 3 fighters for scramble plus some naval.
But I see that the reach to the money islands is better from Queensland so I agree that US/ANZAC can harass better from there and Caroline is rather the “next” move to increase the pressure on JP.