Sumo (相撲 sumō?) is a competitive contact sport where two wrestlers called rikishi face off in a circular area. The sport is popular in Japan and is surrounded by ceremony and ritual. The Japanese consider sumo a gendai budō: a modern Japanese martial art, even though the sport has a history spanning many centuries. The sumo tradition is very ancient, and even today the sport includes many ritual elements, such as the use of salt for purification, from the days sumo was used in the Shinto religion.