RousseauX
Donor
Nuclear weapons didn't stop America from losing in Vietnam though, it didn't stop North Korea from temporarily conquering the South by conventional means, the problem is that there is a real actual political and economic cost of trying to hold onto Manchuria even short of the equivalent of a Korean WarDo you believe that Taiwan would have lasted a month without the US and its aircraft carriers? The only reason that Taiwan had a chance to develop a modern economy was because it was given time to. In TTL Japan would give Manchukuo the necessary time to develop itself. If given the chance, TTL Japan would undoubtedly become a nuclear power. Nuclear deterrence is simply a cheaper solution to keep China away than maintaining a large military and navy. Once the Nuclear Age begins it will become politically impossible for China to ever go to war with Japan again. Think of it like OTL India-Pakistan. They fought a couple wars, then one got the bomb, than the other, and now there isn't anymore warring going on anymore because the costs are now too high to be politically feasible.
And just domestically don't assume Japan will forever ever be dominated by militarist "forever war in North China" types: the fall of fascism in Portugal was owed partially to the unpopularity of Portugal's colonial wars in Angola
The endgame in Manchuria might very well look similar to France in Algeria: a military stalemate which is unpopular at home: Japan cuts and runs and focus its effort on preserving its holdings in Korea