. The American was the first foreign-born wrestler to reach the level of yokozuna.

The sport is highly regimented with many wrestlers living in communal training facilities where food and dress are controlled by ancient traditions.

Onosato's promotion will set up an instant rivalry with Mongolia-born Hoshoryu, who is the other wrestler in Japan to hold the yokozuna title.

The Japanese news agency Kyodo said the two sumo stars are due to meet in a tournament in July in the central city of Nagoya.