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 be promoted after five years in the previous grade, but a 'good' candidate would have to wait eight. There have only been seventeen "judan" (tenth dan) judoka in history, fifteen promoted by the Kodokan and two by the International Judo Federation. None of them are Canadian, but Canada does have a group of more than 100 "kōdansha" (high dan holders), all of whom have devoted much of their lives to Canadian Judo. The late Yoshio Senda became Canada's first "kudan" (ninth dan) in 2007, and since then three more Canadians have been promoted to "kudan" by Judo Canada: Yeiji Inouye