The Japanese martial art Judo was the first of the martial arts to use a colored belt system to mark the progress of its practitioners. Judo's inventor, Dr. Kano Jigoro, introduced the belt system, adapting the traditional Japanese sash, or obi, for this purpose. As part of its modernization, karate adopted the belt system in the 1930s.

Identification
In the different martial arts disciplines, the system of color codification according to rank, or kyu, varies. However, all martial arts that use the colored belt system follow a ranking structure that progresses from 10 to one.

History
Within the colored belt system, the ranking of Number One corresponds to the black belt, which is the ultimate color a martial arts student can achieve. Once a student has been awarded a black belt, the Dan system, a traditional Japanese ranking method, takes over. The Dan system was adapted by Dr. Jigoro from a tradition in Japan that had originated with the game Go in the Edo period, which runs from 1603 to 1868. Students awarded the black belt will then be able to progress from Dan level one through to Dan level 10.

Considerations
Regardless of which martial art students study, they will always begin with a white belt. As their expertise improves, their belt color will change. Traditionally, a belt would be dyed a new color to indicate a student’s ascent in rank.

Theories/Speculation
A popular theory about the origin of the colored belt system is that a student’s belt changed color due to a superstition that prohibited washing it. The black color indicating a high level of accomplishment could then be seen as a sign of all the years of effort and sweat a student would invest in martial arts practice.

Types
A more likely theory about the origins of the colored belt ranking system in the martial arts is simply that the dying process dictated a gradual progression in the color of the belt, from light to dark. The standard color belt ranking system is white, yellow, orange, green, blue, brown, black.