 He was also the author of the first English taekwondo syllabus book, "Taekwon-Do", published by Daeha Publication Company in 1965.In 1972, Choi went into exile in Canada after the South Korean government objected to his introduction of the sport into North Korea, and the South Korea government formed the World Taekwondo Federation (WTF) in 1973 (renamed to WT in 2018).He moved again in 1979 to North Korea where he was welcomed by the government and supported in his project of spreading Taekwondo to the world.