Wikipedia lists multiple battles between the Chinese Red Army and the Nationalists, and also states they joined together to fight the Japanese. It lists multiple engagements/actions from 1927 to 1936.

Claiming Mao "believed in violence" adds nothing new, really. Most revolutionaries believed in violence as a means to reach an end. Nationalists did, too.

I think it's not controversial that Mao had a vision for his country which he tought would make China great, he was a visionary and an ideologue. You don't have to agree with his vision to acknowledge he had one.