Curently CCP in China and KMT in Taiwan both claim its their leadership led to defeat Japan in WWII.  So I like to tell my reader who really defeated Japan in WWII.

Japan occupied one third of the China before 1937 due to old Chiang's unwilling to fight Japan but determine to eliminate CCP and the weakness of KMT soliders. So the Xi An coup（西安事變） happened, Both Eastnorth soliders under general Zhang(張學良) and Mao's CCP wanted to killl him.  USSR instructed Zhou Anglai（周恩來）not to kill him because WWII needed China to fight Japan and Chiang was the leader of the nation at that time.  Chiang survived the coup and forced to fight Japan in exchange of his son's coming back from Russia ( KMT taught people in Taiwan that Zhang was touched by Chiang's patriotic diary then released him.  What a liar!!).   During the 8 years anti Japan war, Chiang used half of his 800 thousands soliders to fight Japan and the other half to confine CCP.  Without the material help of US and the people on both CCP and KMT sides China would not win the war.

Both CCP and KMT with the help of USSR and United States had credits on winning the war.  After the war Chiang knew he needed to continue to destory CCP to be able to consolidate his power as a national leader.  But CCP was no longer as weak as they were in 1937.  Besides there were many CCP spies inside the KMT.  So between 1945 to 1946 although KMT still won war against CCP, but after 1947 CCP got the upper hand (Mao's guerllia and mobile strategy started to take effect)and eventually defeated KMT in late 1949.

The ture hero of anti Japan war were those soliders who fought and defeated Japan.  General Sun Li Ren（孫立人）and his soliders were the heros.  But general Sun was oppressed by old Chiang and his son in Taiwan.

References:
1) http://en.wikipedia.org/wiki/Chiang_Kai-shek
2) http://en.wikipedia.org/wiki/Mao_Zedong