Just as it is often said that Operation Barbarossa is Hitler's biggest strategic blunder (either the whole thing, its timing or execution), what were Chiang Kai-shek's biggest strategic blunders in the Second Sino-Japanese war, and why?
For example, I've often heard that the Battle of Shanghai should not have been fought since it was indefensible (the IJN and air force could provide full support) and the NRA lost its most elite troops. However I've also heard that it was all part of a master plan of luring Japan to overextend. Which is true, or what else would be a big blunder?