When Kano developed Judo’s ranking system, there was no official system in the martial arts; student achievements were usually acknowledged by the presentation of certificates or scrolls. Today, Kano’s system has been adopted by the other martial arts, who have modified it for their needs. Originally, the Judo ranking system consisted only of white and black belt ranking, until the 1930s when Kano created a belt to acknowledge the achievements of high-ranking black belts. The red belt and brown belts were also added. The more extensive system used today was developed after Judo spread outside Japan. Judo instructor Mikonosuke Kawaishi introduced a more complex ranking system, featuring several more colored belts, when he began teaching in Paris in 1935. He felt Westerners would have more incentive to practice if they had a system in which achievement was regularly recognized. He included white, yellow, orange, green, blue and purple belts, awarded before the traditional black and brown belts.
There are two divisions: student, or kyu, and master, or dan. Within the dan, or black belt ranks, there are 10 levels. In traditional Judo practice, only those achieving the rank of godan, or 5th degree black belt, may properly be called a sensei, but in many Western dojos, this term is used for any degree black belt if he is the instructor. There is no official system for granting rank; the instructor decides when a student is ready to progress. In the West, everything up to the brown belt is awarded by the student’s dojo, and black belts are awarded after an exam judged by members of the national judo association.