I'm writing my undergrad thesis on the Chinese Civil War from 1927-37, and I'm specifically looking at why Mao and Chiang teamed up against the Japanese. One of the theories that I'm working with hypothesizes that actors with weaker military forces are more likely to enter into coalitions than those who have stronger military forces. In order to show a correlation, I have to find data on number of enlisted soldiers and number of military hardware (tanks, guns, planes, etc.) that the National Revolutionary Army, the Red Army, and the Imperial Japanese Army had. I can't find this data anywhere, and I was wondering if you guys could help!
As much as I would love to give you data, I have to disagree with your theory, as Chiang Kai-Shek was literally strong-armed into making peace with the Communists in the Xi'an Incident. For his part, Mao wanted to kill Chiang instead of allying with him, but Stalin intervened and forced Mao to do so as well. So this would already tell me that there is a stronger factor at play here.