Karate, Jujitsu, AIKIDO, and Judo are all forms of martial arts that originated in Japan. Karate is a form of unarmed combat that uses punches, kicks, and blocks to defend oneself. Jujitsu is a form of grappling that focuses on joint locks and throws. AIKIDO is a form of self-defense that uses circular movements to redirect an attacker's energy. Judo is a form of martial art that emphasizes throws and pins. All four of these martial arts are popular around the world and have been adapted for use in various sports and competitions.