Sumo Wrestling

The wrestling ring (dohyō)
Sumo matches take place in a dohyō (土俵): a ring, 4.55 metres (14.9 ft) in diameter and 16.26 square metres (175.0 sq ft) in area, of rice-straw bales on top of a platform made of clay mixed with sand. A new dohyō is built for each tournament by the yobidashi. At the center are two white lines, the shikiri-sen, behind which the wrestlers position themselves at the start of the bout. A roof resembling that of a Shinto shrine may be suspended over the dohyō.