But that was worthy and besides the Americans surrender not us majority went on continue the fight and even the filipinos who were captured and release later on fought as guerrillas compare to almost years of loses because majority of chinese were fighting among themselves that's the truth this internal fighting weaken china otherwise Japan would have been contain in china northern provinces and never spread to South East Asia and the war would have ended soonerThe entire Philipinnes was overrun in six months.
If China lost almost every front, the entire China would have been conquered. The Japanese had a massive collaborator army led by Wang Jingwei and Demchugdongrub. The Soviet Union also invaded Xinjiang in 1937 and stationed an entire army in Kumul.
The Japanese controlled less than 25% of the entire China in 1940 and only gained significant amounts of (strategically useless) land in Operation Ichi-go. Their attempt to invade northwest China failed and General Fu Zuoyi and the Muslim Ma warlords defeated their invasion.
China used over 100,000 soldiers in wrest Xinjiang back from the Soviet Union and then to fight the Soviets in the Ili Rebellion. China fought a two front war in WW2.