Chin Taiken, also called Master Chin, is a martial artist and leader of the Chin-Star School.

Biography
When Goku is looking for someone strong to test his power against, an old lady suggested that a man named Master Chin is the strongest person around. Goku runs into Chin's son, Shoken, who had allegedly stolen Rising Dragon's, a member of the Panther-Fang School, wallet.

The Chin-Star school and the Panther-Fang school are bitter rivals, so Chin is eager to defend his school and his son. Chin then uses his signature technique, the Phantom-Star (a variation of the Afterimage Technique), on two of Rising Dragon's goons. When he is ready to fight an awestruck Rising Dragon, he buckles due to his sickness. After Sky Dragon breaks up the scuffle between his brother and Goku, Master Chin agrees to a sparring session with Goku, but once again, his sickness got the better of him.

By now, Chin's sickness is so bad that he cannot compete in King Wonton's martial arts competition against Sky Dragon to decide who is the master of martial arts. After deciding that his son, Shoken is not yet ready, Chin agrees that Goku should take his place. Goku wins the match by using Chin's technique and Chin is then named "The Master of Martial Arts". After the match, Chin and Sky finally put the past behind them as Sky starts anew under Chin as a member of the Chin-Star School.

(Source: Dragon Ball Wikia)