Japanese martial art. Rules of Sumo are simple : two men are pitted against each other in a clay ring.

The first to step out of the circular boundary or touch the ring floor with any part of his body except his feet has lost the match. Few rules and restrictions govern match. However, the paucity of rules is balanced by the number of rituals and ceremonies and the traditional etiquette that is present in sumo.

Sumo truly is a national symbol for the Japanese of the bygone days of samurai honor. The Japanese often refer to sumodo (the way of sumo) as the modern bushido (way of the samurai). Sumo has few shared techniques with Greco-Roman wrestling. In fact, it has more in common with the martial arts of judo and aikido.

Throughout Japan's long and eventful history, sumo has been a valuable part of Japanese culture; whether as a religious ritual, a part of military training, or as a national sport. Sumo has undergone numerous changes, especially from the 15th century to the present. It has changed in social status, going from a form of entertainment for the Gods, to entertainment for the noble, to entertainment for the masses. The final step was to make it the Japanese national sport in the early 19th century, when it began to develop into what is practiced and recognized today.