K-1

K-1 is a world-wide kickboxing promotion founded in Tokyo, Japan by Kazuyoshi Ishii, a former Kyokushin karate practitioner. Its rules are similar to those of kickboxing but they have been simplified to promote exciting matches that may end in a knockout win. The main difference between K-1 rules and kickboxing is the use of knees, allowed in K-1 but not in international kickboxing.