Rank in Judo 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. The
The Canon of Judo mentioned. In the book, Kyuzo Mifune explains his metaphysical view of Judo, its role in Japanese society (and the world), and benefits to the individual player. He notes that Judo initially only included throws, and explains the difference between Judo and Ju-jutsu. He discusses the role of competition in Judo, and the purpose of free practice, randori, and explains that it is an indispensable part of the sport. Although the book mentions the five kata, it does not cover them. Furthermore, it does not cover Atemi-waza, but states that Atemi-waza include strikes, kicks, hits, and attacks using the fist, foot,