Chan Yen was a native of King Mui village, San Woi district of Guangdong province. When he was young, his father Chan Yau Kau sent him to learn Choy Li Fut Kung Fu from the founder's first son Chan On Pak. Chan Yau Kau, himself, was also a student of Chan Heung, Choy Li Fut's founder. Since it is generally difficult for a father to teach his own son kung fu, Chan Yau Kau had his kung fu brother Chan On Pak teach Chan Yen kung fu for him.

After his teacher Chan On Pak passed away, Chan Yen continued his advanced kung fu training and his study of Dit-Da healing arts with his father Chan Yau Kau. Later, his father took over the Hung Sing studio headquarters in King Mui as the head instructor; Chan Yen then helped his father with most of the teaching. After his father retired, Chan Yen officially took over the position as the head instructor in the original Hung Sing studio founded by Chan Heung in King Mui village.

Since his childhood, Chan Yen was a very hyperactive and mischievous kid. His natural ability allowed him to learn Choy Li Fut Kung Fu very easily and he loved to tease other students and make them angry so they would spar with him so he could test his fighting skills. That is how he became the best fighter in the group at that time. Later, even in his senior years, he still loved to tease people into sparring. This is how he gained his nickname Lou Wan Tung (the old naughty kid).

In 1945, Chan Yen went to Kong Moon city to visit his college Chan Cheong Mo. He met a young man named Wong Ming Sang, one of the instructors of the Hung Sing studio run by Chan Cheong Mo in Kong Moon city. He liked this young man's kung fu potential, he asked Chan Cheong Mo for permission to have this bright young man to go to King Mui village for advanced kung fu training. At that time Chan Cheong Mo was 77 years old, most of the advanced kung fu forms were hard for him to teach at the age. Chan Cheong Mo agreed to have Chan Yen help him teach this student. The young man is our Grandmaster Doc-Fai Wong's teacher, he is known in Hong Kong by the name Wong Gong.