History
Sumo is Japan's national sport and is woven with Shinto ritual: it was performed at shrines and the imperial court for centuries. Professional sumo, organised to raise money for temples and shrines, began in Edo (Tokyo) in 1684.
Today the Japan Sumo Association holds six grand tournaments (honbasho) a year, a system in place since 1958. Wrestlers live and train together in "stables" (heya) and climb a strict ranking ladder up to yokozuna, the grand champion.