The dohyō is the sumo wrestling fighting ring. It is mounted on a square platform of clay with the sand on a top. The ring is made by rice-straw bales.

The roof on the top of the ring is looking like a roof of a shinto shrine is called tsuriane and mean to protect the fight from bad spirits.
Before the roof was places on 4 columns but for last 60 years it was suspended from the roof to give a full pleasure of fight watching to the audience.