Choi Hong Hi
Yun was raised in what is now known as South Korea, and is a survivor of both the Japanese occupation of Korea and the Korean War. His childhood education included training in the martial art of Moo Duk Kwan under the master Oh Sae Joon. Subsequently, he twice won the national championships of Korea, and gained the attention of Sang Kyu Shim, who asked him to assist in the teaching of the 1st and 2nd battalions of the Republic of Korea marines; Yun also taught the 1st Cavalry division of the United States Army in Munsan, Korea. It was during this period that Shim introduced him to Choi Hong Hi, from him Yun learned taekwondo along with the Cha Soo Young, Moon Ku Baek, and Jung Joong Sun.