Dan (rank) highest level that might be attained, with instructor certification and judge/judgment authorization being understood as higher-level or more sophisticated. Many arts use between one and ten dan ranks: In some martial arts, black belts are worn for all "dan" grades. In others, the highest grade (10th "dan") wears a red colored belt. In Jūdo and Shotokan 6th to 8th "dan" may wear a red and white-patterned belt and 9th to 10th "dan" may wear a solid red belt. There is some variation even within styles. Generally, belts do not have markings that indicate the actual "dan" grade. Okinawan styles used
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