Judo (柔道) is a martial art which originated in Japan. Judo was developed from Ju-jitsu, and was founded by Jigoro Kano in 1882. The sport became the model of the modern Japanese martial arts, gendai budo, developed from old koryu schools.
Judo literally means "gentle way". Judo takes from ju-jitsu ("gentle art") the principle of using one's opponent's strength against him. Kano saw ju-jitsu as a disconnected bag of tricks, and sought to unify it according to some principle: he found it in the notion of "maximum efficiency". With that, he renamed his art "judo", to indicate his view of it as a means of physical and spiritual development, as well as self-defense.
The focus in judo is on throwing techniques (nage-waza), with groundwork (katame-waza) also a major component. A kind of sparring is practiced in judo, known as randori, meaning "free practice". In randori, players (known as judoka) may attack each other with any judo throw or grappling technique. Striking techniques (called atemi-waza) such as kicking and punching, along with knife and sword techniques are retained in the katas taught to higher ranking judoka (for instance, in the kime-no-kata), but are forbidden in randori, for reasons of safety.
Judoka are ranked according to skill and knowledge of judo, that grade being reflected in the color of his belt: There are two divisions of grades, the student grades (kyu), and the master grades (dan). In the west, the kyu colors run from red (a rank beginner) then white through yellow, orange, green, blue, and brown. In Japan, all kyu grades wear brown belts. All dan grades may wear the Black Belt; seventh and eighth dans may alternately wear a red-and-white belt, while ninth and tenth dans may wear a red belt.
Wearing a red belt as a beginner and again as a tenth dan you have completed the 'circle'. Jigaro Kano was the inventor of the kyu - dan grading system, that soon got adapted by other martial arts such as karate.
Although a fully-featured martial art, judo has also developed as a sport. Judo became an Olympic sport for men in 1964 and, with the persistence of a woman by the name of Rusty Kanakogi, a sport for women as well in 1992. In the west, the sport aspect of judo probably is the most commonly taught. Men and women compete separately (although they often train together), and there are several weight divisions including an open-weight category which anyone may enter.History and philosophy
Techniques
Grading
Styles
Jigaro Kanos Kodokan is the most spread style of judo. Another style is Kosen judo, with the same range of techniques but more Ne-waza (ground techniques). Sport