Kim Young-joon (middle in the second row) poses in a group photo with the board members who listened to their oral defenses and other students also in the defense, at the University of International Business and Economics, Beijing, June 1, 2017. [Photo provided to chinadaily.com.cn]

Kim is widely-known as "Grandpa Kim" among his classmates, as most of them are of the post-1985 generation.

"When we first met, he was in very good health condition and all of my classmates were impressed by his capacity for liquor," his classmate Niu Yang said. "We got along very well with him, and his questions in class were amusing but enlightening for us to understand better the Chinese legal system and laws."

Kim lived in Seuol's famous Gangnam District. He was one of seven who passed the judicial exam held in South Korea in 1965. He worked as a prosecutor for 20 years since 1971 and became a lawyer after retiring from the position.

He came to China in 2007. After two years learning the language, he began to study for his first doctorate under Zhang Jinpan, a prestigious professor in history of the legal system, at the China University of Political Science and Law.

His family have deep connections with China. His son studied at Peking University and his daughter-in-law studied at Beijing University of Chinese Medicine. During their studies in the late 1990s, Kim's granddaughter even enrolled in kindergarten in Beijing. "Her Chinese is better than mine," Kim said proudly.