The precursor to sumo probably originated in China during the Han Dynasty. The first sumo-like match in Japan occurred in 453 at the funeral ceremony of Emperor Ingyō. The sport is also associated with Shinto ritual where a human ceremonially wrestles with a kami, a Shinto spirit or god.
Professional Sumo originated in Japan during the Edo Period. It was then used as a form of entertainment and many of the original wrestlers were probably samurai who were looking for additional income.
The Japan Sumo Association is the current professional Sumo organization. The oyakata make up the members of the association. They are all former wrestlers and are the only people entitled to train new wrestlers. The heya make up the practicing wrestler training stable. The training stable is run by one of the oyakata. There are currently 54 training stables for about 700 wrestlers.
There is a strict hierarchy based upon sporting merit. The wrestlers are ranked and are promoted or demoted according to their previous performance. Two weeks prior to each sumo tournament the Banzuke which lists the full hierarchy is published. This method has been in place since the Edo period.
There are six divisions in sumo: Makuuchi (fixed at 42 wrestlers), Juryo (fixed at 28 wrestlers), Makushita (fixed at 120 wrestlers), Sandanme (fixed at 200 wrestlers), Jonidan (approximately 230 wrestlers), and Jonokuchi (approximately 80 wrestlers). Wrestlers in training enter in the Jonokuchi division and can work their way up to the Makuuchi. The sekitori are the wrestlers in the top two divisions and are the only wrestlers that are salaried. Wrestlers in training receive a subsistence allowance for performing various chores in their training stable....