thumb|upright=0.6|Two children training in judo techniques Judo is a hierarchical art, where seniority of judoka is designated by what is known as the - ranking system. This system was developed by Jigoro Kano and was based on the ranking system in the board game Go.
thumb|upright=0.6|Two children training in judo techniques Judo is a hierarchical art, where seniority of judoka is designated by what is known as the - ranking system. This system was developed by Jigoro Kano and was based on the ranking system in the board game Go