The national sport of sumo traces its origins to an early Shinto ritual to pray for a bountiful harvest, and the professional tournaments of today date to the 17th century during the Edo Period.
The traditional all-male sport in recent years has been dogged by scandals, including the beating death of a young trainee in 2007, alleged marijuana use and even claims of match-fixing. The recent retirement of the brash Mongolia-born yokozuna Asashoryu while still in his prime was prompted by allegations of drunken violence.
Earlier this month, reform-minded former yokozuna and stable master Takanohana, 37, was elected as a new board member of the Japan Sumo Association. Observers view this as a sign that some stable masters are concerned with the way the board members in their 50s and 60s are handling the problems that have eroded sumo's popularity.