Yoon Byung In, who taught Moo Do with Chun Sang Sup in the Choson Yun Moo Kwan, founded the Chang Moo Kwan (development of martial arts training hall) in 1946 at the YMCA in Jong Ro, Seoul. The Chang Moo Kwan was represented with a symbol of two dragons.
Yoon spent his childhood in Manchuria and learned Jooanpa, a Chinese martial art (more commonly known as, Chuan-fa). In the 1940's just before Independence Day, he went to Japan to study abroad. While there, Yoon claims he studied karate under the direction of Kanken Toyama, founder of Shudokan karate, earned a 5th Dan, and was team captain at Nihon University.
After Korea's independence, he returned to Korea became the physical education instructor at Kyung Sung Agricultural School and started teaching Moo-do with Chun Sang Sup in the Choson Yun Moo Kwan on September 1, 1946. Later in 1946, he opened the YMCA Kwon Bup Bu in nearby Jong Ro, Seoul, teaching what he called Kwon-bop (fist method). Yoon had a good relationship with Choson Yun Moo Kwan's Chun Sang Sup and once Chun and Yoon were called brothers because they trained so much together. Chun Sang Sup's younger brother Chun Il Sup said: "YMCA Kwon Bup Bu's Yoon Byung In and Lee Nam Suk trained with the Choson Yun Moo Kwan in the beginning, so I can say the Yun Moo Kwan and the YMCA Kwon Bup Bu were brother Kwans." Yoon Byung In was basically a traditional Moo Do man. His body was small, his behavior was blunt, and he did not know how to wear his clothes and shoes fashionably. He wore a pair of oversized US Army boots. His left little finger had been cut off so he wore pair of special white gloves, even in the summer. He taught his martial art (Ju An Pa Kwon Bup) to his students according to their body sizes, so the students could learn martial arts that suited their body specialty.