Wikipedia
also known as ushi-zumo or Bull sumo, is a spectator sport native to the Ryukyu Islands of Japan ( Okinawa Prefecture and the Amami Islands of Kagoshima Prefecture). It is also held in other regions of Japan, such as Iwate Prefecture, Niigata Prefecture, Shimane Prefecture, and Ehime Prefecture. Although sometimes known to Westerners as "Okinawan bullfighting", it is drastically different from the Spanish or Portuguese style of bullfighting where the matches are between a bull and a human, with blood being spilt. Tōgyū has more in common with northern Portugal's sport of chegas and the Swiss sport of cow fighting.
During matches, the bulls lock horns and attempt to force each other to give up ground. Each bull has a coach who helps to keep the bulls locked in conflict and encourages their bull to win. The match is over when one of the bulls tires and withdraws, losing the match. The coaches take great care to prevent the bulls from harming each other and the fight is immediately over if one of them accidentally gores the other.