Yoon returned to Korea in 1945. On September 1, 1946, Yun began teaching kongsoodo and kwonbup at Kyungsung Agricultural High School. Shortly thereafter, he also began teaching at the Yunmookwan and also established his own school, the Kwonbup Bu, at the Jong No YMCA. Yoon later created his own style and called it Kwon Bop Kong Soo Do. Unlike many other post-war taekwondo kwans, early Chang Moo Kwan martial arts wasn't solely based on Karate and included significant amounts of Chinese Kung Fu.