Makuuchi (幕内^?) or makunouchi (幕の内^?) is the top division of professional sumo. Its size is fixed at 42 wrestlers (rikishi), ordered into five ranks according to their ability as defined by their performance in previous tournaments.

This is the only division that is featured on NHK's standard live coverage of sumo tournaments. The lower divisions are shown on their satellite coverage, with only makuuchi broadcast having bilingual commentary.

Makuuchi literally means "inside the curtain", a reference to the early period of professional sumo, when there was a curtained-off area reserved for the top ranked wrestlers to sit prior to appearing for their bouts.

Wrestlers are considered for promotion or demotion in rank prior to each grand tournament according to their performance in the one previous. Generally, a greater number of wins than losses (kachikoshi) results in a promotion, and the reverse (makekoshi) results in demotion. There are stricter criteria for promotion to the top two ranks, which are also privileged when considered for demotion.

Yokozuna may refer to:

Sumo (相撲, sumō^?) is a competitive full-contact sport where a wrestler (rikishi) attempts to force another wrestler out of a circular ring (dohyō) or to touch the ground with anything other than the soles of the feet. The sport originated in Japan, the only country where it is practiced professionally. It is generally considered to be a gendai budō (a modern Japanese martial art), though this definition is incorrect as the sport has a history spanning many centuries. Many ancient traditions have been preserved in sumo, and even today the sport includes many ritual elements, such as the use of salt purification, from the days when sumo was used in the Shinto religion. Life as a rikishi is highly regimented, with rules laid down by the Sumo Association. Most sumo wrestlers are required to live in communal "sumo training stables" known in Japanese as heya where all aspects of their daily lives—from meals to their manner of dress—are dictated by strict tradition.

In addition to its use as a trial of strength in combat, sumo has also been associated with Shinto ritual, and even certain shrines carry out forms of ritual dance where a human is said to wrestle with a kami (a Shinto divine spirit). It was an important ritual at the imperial court. Representatives of each province were ordered to attend the contest at the court and fight. They were required to pay for their travels themselves. The contest was known as sumai no sechie, or "sumai party."