What material is a sumo wrestling ring traditionally made of?

What-A-Mess

"Sumo matches take place in a ring called a dohyō. The dohyō is made of a mixture of CLAY and SAND spread over the top. It is between 34 and 60 cm high. It is removed after each sumo tournament, and in the case of Nagoya, pieces are taken home by the fans as souvenirs. A new dohyō is built prior to each tournament by the yobidashi, who are responsible for this activity. The yobidashi also build the dohyō for training stables and sumo touring events. The circle in which the match takes place is 4.55 meters in diameter and bounded by rice-straw bales called tawara, which are buried in the clay. The rice bales are ⅓ standard size and are partially buried in the clay of the dohyō. Four of the tawara are placed slightly outside the line of the circle. In olden times this was to allow rain to run off the surface, when sumo tournaments were held outdoors in the open." http://en.wikipedia.org/wiki/Sumo Mar 22 07, 4:09 PM