Formed in 1937, when the Communist Red Army (
红军) in the northwest joined the united front against Japan and became, on paper, part of the Nationalist army, the
国民革命军. Under
朱德 it fought mostly guerrilla war behind Japanese lines in North China, while the
新四军 (New Fourth Army) fought in central China. After 1945 both became part of the
解放军.