But in a sweeping new move that has also outlawed tattoos and long nails, the sport’s authorities have declared that any failure to adhere to the new rules will leave wrestlers a whisker away from trouble.
“Wrestlers must preserve their personal hygiene,” Japan Sumo Association elder Oguruma told reporters after a board meeting.
“Officials and referees will be on the lookout. The sumo ring is sacred and it’s important spectators don’t see anything unsightly.”
The move is seen as an attempt to clean up the sport following a series of scandals including match-fixing and violence in recent years. In October, the JSA issued a declaration pledging to eradicate violence from the sport.
In 2017, grand champion Harumafuji’s career was brought to an abrupt end after he was charged over a brutal assault on a rival while out drinking.
There was also controversy in April 2018 when women who had rushed to the aid of a man suffering a stroke while giving a speech at a sumo event in Japan were told to leave the ring because of rules banning women from the sacred space.
The incident led to the JSA offering an embarrassing apology following a deluge of criticism on social media.