This is another book that covers more specifically the period.

http://www.amazon.com/Battle-China-M...=the+china+war

I read it and it was extremely good. You come away with a huge respect for the endurance and determination of the Chinese people, and surprisingly considering what we've been told for years, Chiang and the KMT.

From what I remember, Japan was interested in keeping the part of China they occupied and did what it took to do that. They never had any real problem with either Nationalist or Red guerrilla forces. Nationalist guerrilla forces fought to support Nationalist conventional forces and were mostly destroyed. Communists, after the 100 regiments attacks mostly concentrated on preserving their forces. If I remember correctly they ended up stronger at the end of the war than at the beginning.

Perhaps one thing that can be learned is the importance of having a sanctuary and a source of external supply. The Chinese didn't have any of that in an important way until 1945.