Dan (rank) highest level that might be attained, with instructor certification and judge/judgment authorization being understood as higher-level or more sophisticated. Many arts use between one and ten dan ranks: In some martial arts, black belts are worn for all "dan" grades. In others, the highest grade (10th "dan") wears a red colored belt. In Jūdo and Shotokan 6th to 8th "dan" may wear a red and white-patterned belt and 9th to 10th "dan" may wear a solid red belt. There is some variation even within styles. Generally, belts do not have markings that indicate the actual "dan" grade. Okinawan styles used
Judo and Dong-Sik Yoon. Kano Jigoro's Kodokan judo is the most popular and well-known style of judo, but is not the only one. The terms judo and jujutsu were quite interchangeable in the early years, so some of these forms of judo are still known as jujutsu or jiu-jitsu either for that reason, or simply to differentiate them from mainstream judo. From Kano's original style of judo, several related forms have evolved—some now widely considered to be distinct arts: Kano's vision for judo was one of a martial way that could be practiced realistically. Randori (free practice) was a central part