History of the Dan System
The systematic use of belt color to denote the rank was first used in Japan by Jigoro Kano, the founder of judo, who first devised the colored belt system using obi (sash), and awarded the first black belts to denote a Dan rank in the 1880s.
The Dan system has been adopted by most legitimate martial arts and recognized worldwide as the Black Belt ranking standard. Many styles award Shodan (1st Degree) through Judan (10th Degree). A number of styles (such as Bujinkan, created by Masaaki Hatsumi) include additional levels of Judan which for consistency are also referred to as 11th - 15th Degree. These are actually steps within the rank of Judan, as Shodan to Judan are the traditional Dan levels.