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
Judo in Canada notably in Japan. It has received relatively little attention in Canada, but Judo research has been conducted by Canadians working in several different disciplines. The most widely cited publications are journal articles and books written by sports scientists. The earliest, "A physiological profile of the Canadian judo team" by A.W. Taylor and L. Brassard, was published in "The Journal of Sports Medicine and Physical Fitness" in 1981. The similarly titled "Physiological profiles of the Canadian National Judo Team" was published by S.G. Thomas, M.H. Cox, Y.M. LeGal, T.J. Verde, and H.K. Smith in the "Canadian Journal of Sport Sciences" in