In sumo wrestling, what is the diameter of the raised dohyo fighting ring?

The diameter of a sumo wrestling dohyo fighting ring is 4.55 metres.

The dohyo is a raised clay platform covered with a thin layer of sand. Its circular contest area is marked by rice-straw bales called tawara. The four central bales are partly buried in the clay, while the remaining bales form the visible boundary.

The ring’s size is standardized, although the platform surrounding it can be larger. Wrestlers lose when any part of the body other than the soles of the feet touches the ground inside or outside the ring, or when they step beyond the tawara. A bout can therefore be decided by a very small movement near the edge.

The dohyo is not simply a visual arena: its construction and ceremonial purification are important parts of sumo tradition. The Japan Sumo Association maintains the official rules and tournament standards, while referees, or gyōji, judge contests from inside the ring.