Cherished for its serenity and deep ties to Japanese culture, sumo wrestling’s floundering reputation was dealt its latest blow yesterday when one of the ritualistic sport’s grand champions retired over a brawl with a junior fighter.

Harumafuji, one of four reigning grand champions – or yokozuna – left a cloud of shame hanging over Japan’s oldest sport as he bowed out in disgrace following the fight in a restaurant-bar, in which it is claimed he struck another wrestler with a beer bottle.

"As yokozuka I feel responsible for injuring Takanoiwa and so will retire from today," Harumafuji on Wednesday told a news conference in Fukuoka, southern Japan, the site of the most recent tournament.

"I apologise from my heart to the people, sumo fans, the Japan Sumo Association, to supporters of my stable [gym] and my oyakata [coach] and his wife for causing such trouble."

Harumafuji, 33, gave no further details of the incident, which is currently under investigation by police. Media reports suggested he attacked Takanoiwa, 27, leaving him with a fractured skull and concussion, and forcing him to miss the latest tournament.