The main principle behind SJF is that America spends all their income in the Pacific for 5-7 rounds (depending on the board situation and dice results, of course.) After that, they split their income (as they earn more than what Japan + Italy earn in any given round at this point.)
To augment their defense, India and Australia put submarines and destroyers in the water. Australian fighters can land on Islands to add additional air support. This forces Japan to keep their aircraft near home else get pinned early in the game.
SJF is not a winning move! You do not take Japan! Ever! Unless they leave it undefended of course. That’s not the idea! The idea is to stop Japan’s growth. Once India and Australia are earning more than Japan, they can take over from there and you can go back to crushing Germany with the lion’s share of your income.
I’ve seen games where the allies have recovered from India, England and Australia being lost, and games where the fall of Russia proved meaningless because the allies are THAT STRONG!
That’s a major problem in my book. I cannot speak for anyone else, but that is a MAJOR PROBLEM in my book! If Russia falls, the game should be over. If India and Australia fall, the game should be over. If Germany or Japan falls, the game should be over. IMHO.