Sumo
Sumo (相撲, sumō) is a competitive contact sport where two wrestlers (rikishi) attempt to force one another out of a circular ring (dohyo) or to touch the ground with anything other than the soles of the feet. The sport originated in Japan and is still very popular there today, being the only country where the sport is practiced professionally. The Japanese consider sumo a gendai budō: a modern Japanese martial art, even though the sport has a history spanning many centuries. The sumo tradition is very ancient, and even today the sport includes many ritual elements, such as the use of salt for purification, from the days sumo was used in the Shinto religion. Life as a rikishi is highly regimented, with rules laid down by the Sumo Association. Professional sumo wrestlers are required to live in communal "sumo training stables" known in Japanese as heya where all aspects of their daily lives - from meals to their manner of dress - are dictated by strict tradition. See here for a list of the active heya in sumo.