The Japan Sumo Association holds tournaments every other month and each tournament lasts for 15 days. Each sumo wrestler must fight a match everyday during the tournament otherwise it’s considered a loss. There are six ranking divisions; Makuuchi, Jūryō, Makushita, Sandanme, Jonidan, and Jonokuchi. Furthermore, there are five rankings within the top Makuuchi division; Yokozuna, Ōzeki, Sekiwake, Komusubi, and Maegashira. After each tournament, a wrestler’s ranking will be revised based on their result except for Yokozuna. Once a wrestler becomes a Yokozuna, he will never be demoted. But Yokozuna are expected to be the top sumo wrestlers and it is disgraceful and dishonorable if one does not achieve good records for several tournaments. Usually a Yokozuna will retire when he starts failing to win or even to be included in championship matches. Please click here for details on sumo.