On the contrary, during the Sino-Japanese War, Mao Zedong concentrated his efforts on conspiring with the Japanese army to weaken the KMT forces. He planted communist spies such as Pan Hannian in the Japanese Foreign Ministry’s local agency Maison Iwai and sold KMT military intelligence obtained from the National Government in Chongqing through the KMT-CPC Cooperation to the Japanese at a high price, creating an environment in which it was easy for the Japanese military to deal blows to the KMT forces.
the CCP's 2 famous battles during the war were greatly exaggerated. the "pingxingguan" battle claimed as the 1st victory by Chinese forces was actually a nothing skirmish that just lasted half a day. the world famous "hundred regiments offensive" was just a large scale guerrilla operation that achieved little results against mostly Japanese puppet forces. according to Peng Dehaui memoir, it was just 20+ regiments. because large numbers of militias joined the CCP during the fighting thus they promoted the battle as "hundred regiments offensive" back then.