Yeah, a math error like leaving a Capital open is obviously fatal, balance be damned, unless Japan in in position to take a capital of it’s own the same round or next. Which is not impossible. :)
RE: Bids, You’ve got lots of options! I believe that the going tournament bid for the allies is 13, but I have seen a range here from 11-20+. The rules for placing bid units usually specify that:
1. At max one unit can be placed per territory/SZ, and
2. Bid units may only be placed where there were already other units belonging to that power.
Destroyers in the Atlantic and Russian Infantry/Fighter are popular choices.
Personally, I think my option (posted in this thread) is fun: instead of a bid, give the allies a free ‘colonial’ Industrial Complex + AA Gun to be placed together anywhere they like before the game starts, then permanently boost the value of that Territory by +1 IPC (but not above 3). So a 1 IPC territory is now worth 2; a 2 IPC territory would now be worth 3; and anything 3 and up keeps it’s OOB value. I think it makes the whole mega-Japan much less inevitable… or at least gives mega-Japan something else to kill besides/before Moscow.
India, Australia, and Sudan make really interesting choices for this sort of ‘fixed’ bid.
Beyond that, consider two other popular options that fix issues that should probably not survived playtesting (in my opinion):
1. Move the DOA China fighter towards Russia a TT or two (or just let its placement within China be determined by the US player), and
2. Close the Turkish Straits to the Italian Caucasus Kamikaze. At least, close UKR and CAUC to sea invasions.