well, china suffered about 3 quarters of Japanese Empire's army.
Kuomintung combated with 4-fifth, and Communist guerrila fought with 1-fifth. (in the past generation nearly nobody knew that Kuomintung cooperated with us and believed they were on the japan's side!)
Japan's invasion began in sept.18 1931 (ironically when the surrender ceremony ended on Missouri battleship, the time was 9:18.) 9.18 to China is like 12.7 to America. And we did nothing to resist
The real war began in 1937---two years before the Eruope fell into the war.
About that war, i have many to say. So i will not talk about it too much here.
if you are interested in some parts of it.
At your service, sir