After World War I, then, the main elements in the Chinese political situation were the Kuomintang, the communists, and the Japanese invaders. ... In 1926 Chiang's forces began a campaign of persecution and assassination against them; in 1927 they were expelled from the Kuomintang.
https://bigsiteofhistory.com/china-after-world-war-one-the-non-western-world/
I hope this helps :)