During the Japanese occupation of Korea, all facets of Korean identity, including folk culture, language and history, were banned in an attempt to erase Korean culture. Koreans were forced to adopt Japanese names and worship at Shinto shrines; Korean-language newspapers and magazines were banned; and during the war, hundreds of thousands of Koreans were forced into service to support Japanese war efforts. Martial arts such as taekkyeon (or subak) were also prohibited during this time; however, taekkyeon survived through underground teaching and folk custom. During the occupation, Koreans who were able to study in Japan were exposed to Japanese martial arts—in some cases receiving black belt ranking in these arts. Others were exposed to martial arts in China and Manchuria.
When the occupation ended in 1945, Korean martial arts schools (kwans) began to open in Korea under various influences. There are differing views on the origins of the arts taught in these schools. Some believe that they taught martial arts that were based primarily upon the traditional Korean martial arts taekkyon and subak, or upon a variety of martial arts, including kung fu and karate. Others believe that these schools taught arts that were almost entirely based upon karate. The book 5,000 years of Korean martial arts points out how Japan tried to erase Korean martial arts history by altering various Korean traditions and practices. How this impacted the perception in today's history is difficult to assess. The Japanese efforts ranged from damaging alterations to monuments of Korean conquests/achievements to facile alterations such as changing the image of Korea's traditional map from a tiger form to a rabbit form. The Japanese leadership of the time believed that by blocking the knowledge of younger Koreans, they could be led to believe they were not warriors in history but a passive race, and so the occupation would be easier. Historians of the time have stated, "Teachers of Japanese martial arts were the only approved instructors. This situation began the amalgamation of Japanese martial arts with the remaining fragments of the Korean systems still in general circulation." Taking all of these factors into consideration, it is difficult to determine who developed the original technique that is praticed in the various martial arts. In any case, after the occupation, the Koreans recompiled the ancient Korean arts and taekwondo was nominated as a national martial art in 1971.
In 1952, at the height of the Korean War, there was a martial arts exhibition in which the kwans displayed their skills. In one demonstration, Nam Tae Hi smashed 13 roof tiles with a punch. Following this demonstration, South Korean President Syngman Rhee instructed Choi Hong Hi to introduce the martial arts to the Korean army. By the mid-1950s, nine kwans had emerged. Syngman Rhee ordered that the various schools unify under a single system. The name "taekwondo" was either submitted by Choi Hong Hi (of the Oh Do Kwan) or Song Duk Son (of the Chung Do Kwan), and was accepted on April 11, 1955. As it stands today, the nine kwans are the founders of taekwondo, though not all the kwans used the name. The Korea Taekwondo Association (KTA) was formed in 1959/1961 to facilitate the unification. Shortly thereafter, taekwondo made its début worldwide with assignment of the original masters of taekwondo to various countries. Standardization efforts in South Korea stalled, as the kwans continued to teach differing styles. Another request from the Korean government for unification resulted in the formation of the Korea Tae Soo Do Association, which changed its name back to the Korea Taekwondo Association in 1965 following a change of leadership.
One source has estimated that taekwondo is practiced in 123 countries, with over 30 million practitioners and 3 million individuals with black belts throughout the world. The South Korean government has published an estimate that taekwondo is practiced by 70 million people in 190 countries. It is now one of only two Asian martial arts (the other being judo) that are included in the Olympic Games; it became a demonstration event starting with the 1988 games in Seoul, and became an official medal event starting with the 2000 games in Sydney.