He is believed to be the first Korean national to study Chuan Fa (Chinese Gung Fu) in China and to return to teach it in Korea.
During his elementary years, after diligent efforts to impress a Mongolian Chuan-fa master[1], the child Byung-In was permitted to study Chuan Fa or Gung Fu.
[3][2] Yoon studied Chinese Chuan Fa under the guidance of a Mongolian instructor in Manchuria for unspecified time.
[5][6][7] Yoon soon became the captain of Nihon University's karate team and eventually was awarded a master's certificate and the rank of 4th dan by Toyama.
Early in his Seoul Kwan, Yoon taught some Kung Fu forms, however specifics of the curriculum remain unspecified.
When Yoon Byung-in arrived to DPRK's side, he would be imprisoned at Gojae-do Island as prisoner of war.
[15] The Mongolian quan fa master who taught Yoon chinese martial arts remains unknown.
It is speculated that the style this Mongolian martial artist taught to Yoon was either Changquan and/or Yang-style tai chi.
[8] One of the styles of quan fa that Toyama had studied in Taiwan was tai chi, and he is known to have taught this to several of his advanced students, including Yoon.
[3] It has been reported that in mid-1960s, Yoon Byung-in served as a martial arts instructor for Korean People's Army and has contributed to the development of Gyeoksul.