The winner of a sumo bout is either the first wrestler to force his opponent to step out of the ring, or the first wrestler to force his opponent to touch the ground with any part of his body other than the bottom of his feet. On rare occasions the referee or judges may award the win to the wrestler who touched the ground first; this happens if both wrestlers touch the ground at nearly the same time and it is decided that the wrestler who touched the ground second had no chance of winning as, due to the superior sumo of his opponent, he was already in an irrecoverable position. There are also a number of other rarely used rules that can be used to determine the winner. Matches often last only a few seconds, as usually one wrestler is quickly ousted from the circle or thrown to the ground.
Sumo Wrestling is a Japanese form of wrestling characterized by the immense size of the wrestlers and the traditional garb worn by all competitors. In Sumo Wrestling competitors attempt to win a match by forcing their opponent out of a small circle or by forcing them to touch the ground with anything but their feet. Sumo wrestling is a highly competitive Japanese contact sport involving two wrestlers pitted against each other in an attempt to force one another outside of a circular ring, or to touch the ground with any body part other than the soles of their feet. Japan is the only country where the sport is practiced professionally.
Over time, sumo's popularity has changed according to the whims of its rulers and the need for its use as a training tool in periods of civil strife. The form of wrestling combat probably changed gradually into one where the main aim in victory was to throw one's opponent. The concept of pushing one's opponent out of a defined area came some time later. It is believed that a ring, defined by more than the area given to the wrestlers by spectators, came into being in the 16th century as a result of a tournament organized by the then principal warlord in Japan, Oda Nobunaga. At this point wrestlers would wear loose loincloths, rather than the much stiffer mawashi of today. During the Edo period, wrestlers would wear a fringed kesho-mawashi during the bout, whereas today these are worn only during pre-tournament rituals. Most of the rest of the current forms within the sport developed in the early Edo period. Professional sumo can trace its roots back to the Edo Period in Japan as a form of sporting entertainment. The original wrestlers were probably samurai, often ronin, who needed to find an alternative form of income.