Kickboxing originated in Japan in the 1950s and spread to North America and Europe in the 1970s. The World Kickboxing Association was founded in the 1970s and is now the largest kickboxing organization with over 100 member countries. Kickboxing gained widespread popularity in the 1990s with the introduction of special rules for competitions. It is now practiced by an estimated 2-3 million people in the UK.