Japanese Prime Minister Shinzo Abe weighed in on the debate, while news of Harumafuji’s demise even nudged North Korea’s latest missile launch off top spot on many news programmes on Wednesday morning.

Yokozuna are expected to be beyond moral reproach but the writing was on the wall for Harumafuji after he confessed to hitting Takanoiwa for texting his girlfriend while he was scolding him over his poor attitude.

The 33-year-old Harumafuji, who reached sumo’s hallowed rank five years ago and whose real name is Davaanyam Byambadorj, denied reports he had used a beer bottle in the attack but admitted punching Takanoiwa and bashing him with a karaoke remote control.

Takanoiwa, 27, was hospitalised after suffering concussion and a fractured skull base in the brawl, which broke out at a bar in the western Japanese city of Tottori during a regional sumo tour in late October, according to local media.

His stable master subsequently reported the incident to the police, who invited Harumafuji in for questioning.

Prime Minister Abe, who was busy dealing with Pyongyang’s missile test, expressed disappointment over sumo’s latest scandal during a scheduled parliament session.

“This incident of violence in the world of sumo, while still under investigation by the Japan Sumo Association, is extremely regrettable,” he told the upper house.

“First of all it is important to clarify the facts quickly, then the sports ministry will take appropriate measures.”

The PM’s words were echoed by Yoshimasa Hayashi, the education and sports minister.

“We have to absolutely eradicate violence in sport,” he said.

“People involved in sumo must be aware that sumo is the oldest sport in Japan. They must act responsibly to prevent a repeat of this violence and never betray Japanese people’s expectations.”

The furore has reopened old wounds in the closeted world of sumo after an increase in violence, allegations of illegal betting, links with crime syndicates and drugs busts shook the roly-poly sport in recent years.

A sumo stable-master was sentenced to six years in prison in 2007 after a trainee wrestler was beaten to death, triggering outrage across Japan.

Another gym boss narrowly escaped criminal punishment after whacking three wrestlers with a golf club for breaking curfew.

The 135-kilo Harumafuji, whose nifty technique makes up for his relative lack of size, won nine Emperor’s Cups before his fall from grace.

Historians claim sumo dates back more than 2,000 years and the sport retains many Shinto religious overtones.

Breaches of its strict protocol are frowned upon, although the JSA has been accused of picking on Mongolian wrestlers, who critics claim lack “dignity”.

However, the trailblazing Asashoryu stretched their patience to breaking point with his repeated rule-breaking, despite roaring to 25 major championships.

He was ordered to clean up his act after a sparking a soapy punch-up with a rival wrestler during a soak in a communal bath.

Asashoryu was subsequently banned for forging a doctor’s note for an apparent back injury before being caught playing in a charity football match wearing a Wayne Rooney shirt.

Another Mongolian grand champion Hakuho, seen as a gentle giant, has battled almost single-handedly to repair sumo’s tarnished image.

But even he has been accused of breaching etiquette by arguing about decisions, most recently on his way to a record-extending 40th championship earlier this month, prompting more tut-tutting from officials.