Lee Chang-ho
Choi Cheol-han is a South Korean professional Go player. He is the fourth youngest (12 years 2 months) to become a professional Go player in South Korean history behind Cho Hun-hyun (9 years 7 months), Lee Chang-ho (11 years 1 months) and Cho Hye-yeon (11 years 10 months). His nickname is "The Viper".