Dan (rank) is by far the most recognizable symbol to the general public. The highest dan ranks are sometimes reserved for the founder or leaders of a style and only high-ranking students can be promoted to them. For example, only five living people hold a tenth dan in judo and only about thirty-five worldwide have been promoted to the rank since its inception; of those 10th dan promotions only fifteen were conferred by the Kodokan, all of them to Japanese judoka. This has led to upper level ranks becoming extinct in some arts. In other styles, the dan ranks are not 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