He appears to have left his russian forces east, for the long game. This makes taking moscow much easier, difficult to fail really.
If you don’t J2, then you have to consider what you’re gaining by one more turn of positioning and building up, vs. moving forward now. Sometimes these plans involve abusing the peace (by passing through the enemy blockers), but if that’s not true, the delay will tend to make the Allies stronger and Japan weaker.
Since you didnt’ go for extra TTs, you may be correct that staying the course is a good move–build on the continent and focus on crushing China. But until you declare war, you don’t need one giant megafleet, its just hanging out waiting for war. Waiting until the last minute to declare total war tends to leave Japan’s income low and make India too strong to take. Their starting advantage is wasted because the relative strength of the allies increases in lockstep in turns 1-4.
There are also alot of yummy pieces on the board to destroy this turn that will be safe next turn. And don’t forget what I said up above, the UK “bunt” is usually a solid move (UK declares war, can move into Yunnan if it wants, moves 1 ship among your fleet, your transports cannot load unless the boys stayed on board. USA stays out 1 extra turn, but UK and ANZAC get 15$ and a whole turn to goof around)
During a classic J1, you can strip out all of UKPACs income, suffocating it. This is a strong Japanese plan, open hard, no factories early, crush UK income. The only problem is you need to defend SZ6 from game start, bigtime.