Kudo (formerly known as Daido Juku) is a very intense Japanese Mixed Martial Art, based on a combination of Kyokushin Karate and Judo. It was initially created by Kyokushin fighters who liked the idea of tough, full-contact, “knockdown” Karate, but felt that the Kyokushin rules against head strikes were too restrictive.
They developed a special protective helmet and began allowing full-power strikes to the head. They also included throws and submissions, although Kudo rules emphasize stand-up fighting by forcing the fighters to return to their feet if a submission hold is not achieved almost immediately after a fall.