It makes sense they support the parts of the KMT who fought in WW2 against Japan, considering the amount of fighting that was done. AFAIK Mao focused on getting his forces into a position where they could wage guerilla warfare and let the KMT do most of the heavy lifting. This way, he could let rightwing infighting run its course while getting communist troops experience so they could be ready to fight whichever side came out on top.
The CPC also had a lot of cells all over Manchuria that were just waiting for the perfect moment to strike, sometimes seizing military bases with weapons as simple as spears.
It makes sense they support the parts of the KMT who fought in WW2 against Japan, considering the amount of fighting that was done. AFAIK Mao focused on getting his forces into a position where they could wage guerilla warfare and let the KMT do most of the heavy lifting. This way, he could let rightwing infighting run its course while getting communist troops experience so they could be ready to fight whichever side came out on top.
The KMT did most of the heavy lifting because they governed almost the entire country while the CPC controlled a single, very poor province.
The CPC also had a lot of cells all over Manchuria that were just waiting for the perfect moment to strike, sometimes seizing military bases with weapons as simple as spears.
For sure, they were very active during the war, both covertly as you say, and more directly through the 8th Route Army.