Rank in judo

In judo, improvement and understanding of the art is denoted by a system of rankings split into kyū and dan grades. These are indicated with various systems of coloured belts, with the black belt indicating a practitioner who has attained a certain level of competence.

Practitioners of Judo (柔道家, Jūdōka) are ranked according to their skill and knowledge, and, for high ranking dan grades, their contribution to the art. Their rank is indicated by the colour of belt that they wear. There are two broad categories of rank: those who have attained a level of competency at which they are considered worthy of a black belt (黒帯, kuro obi) and who hold dan (段) grades and those who are yet to attain that level and who hold kyū (級) grades. Those who hold dan grades are collectively termed Yūdansha (有段者) (literally "person who has dan") and those with kyū grades are Mudansha (無段者), literally "person without dan". High grade "Judoka" 5th dan to 10th dan are Kōdan-sha (高段者) literally "person of high rank" and the "esteemed" grades of 6th, 7th, and 8th dan have alternating red and white panel belts (紅白帯) Kōhaku-obi, and for the "venerable" Kōdan-sha (高段者) "high ranking" grades of 9th and 10th dan, their belts are solid and bright red.

This ranking system was introduced by Kanō Jigorō, the founder of judo, in 1883. However, the current system is not the original one, but based on Kanō's last system introduced between 1926 and 1931, with some modification shortly after Kanō's death in 1938. The first dan grades were awarded to his students Saigō Shirō and Tomita Tsunejirō. Since then it has been widely adopted by other modern martial arts.

In the current system as in use in Japan, there are six student grades ranked in descending numerical order. Beginners were given the rank of sixth kyū (六級, rokkyū) and wore a light blue belt. Once they had passed an elementary level of instruction, they were promoted to fifth kyū (五級, gokyū), when they would adopt the white belt. This they wore through fourth kyū (四級, yonkyū). The remaining three grades ,third kyū (三級, sankyū), second kyū (二級, nikyū) and first kyū (一級, ikkyū) were all indicated with brown belts (for seniors) or with purple belts (for juniors).

1st kyū is the last kyū rank before promotion to first degree black belt (shodan). There are (in practice) 10 dan ranks, which are ranked in ascending numerical order.

The ninth (kudan) and tenth degree black belt (jūdan) and, theoretically, those higher, have no formal requirements. Only 15 individuals have been promoted to the rank of Kōdōkan 10th dan. On January 6, 2006, three individuals were promoted to this rank simultaneously: Daigo Toshirō, Ichirō Abe, and Ōsawa Yoshimi. This is the most ever at the same time, and the first in 22 years. No one has ever been promoted to a rank higher than 10th dan, but in theory the judo rank system is not limited to 10 degrees of black belt. As an educator by profession, Kanō believed that there should be no end to an individual's learning, and therefore no limit to the number of dan ranks. The English language edition (1955) of Illustrated Kodokan Judo, edited by the Kōdōkan, says:

There is no limit ... on the grade one can receive. Therefore if one does reach a stage above 10th dan ... there is no reason why he should not be promoted to 11th dan.

This statement was later clarified, however. Essentially, the dan-rank system was capped at 10 after the death of Kanō. In that respect, in the November 1963 issue of Jūdō, the Kōdōkan's official magazine, the Kōdōkan responding to the question "Do the 11th and 12th Dan really exist?" *clarifies that the hierarchy now stops at 10 and that the Kōdōkan does not envisage any nominations to these grades.