After his expulsion from school, Choi's father sent him to study calligraphy under one of the most famous teachers in Korea, Han Il Dong. His father felt that Choi could later use these skills to carve tombstones. Later in his life, Choi became a prize-winning calligrapher. Han, who was also a master of Taekkyon, was concerned over the frail condition of his new student and began teaching Choi the rigorous exercises of Taekkyon to help build his body. Choi studied under Han for seven years.
In 1937, Choi became interested in studying Western culture, sciences and laws. His friends had been studying the West in Japan and they encouraged him to come to Japan. Choi's father was satisfied with his proficiency in calligraphy so he sent Choi to Japan to further his education
Shortly before leaving for Japan, Choi had an argument with a massive professional wrestler, named Hu. Choi lost all his money he was to use in Japan to Hu during a card game and Hu refused to return some of the money. As Hu turned to leave, Choi threw a ink well at him that hit him on the forehead and knocked him unconscious. Choi grabbed the money and left for Japan. Hu promised to tear the youth limb from limb at their next encounter. This threat seemed to give a new impetus to young Choi’s training in the martial arts. Choi has explained that after this event, "I resolved to become a black belt holder in karate while I was in Japan."