Former sumo grand champion Harumafuji was charged Thursday for a brutal assault on a rival wrestler while out drinking in a scandal that has humiliated Japan's ancient sport.

The Mongolian former "yokozuna", sumo's highest rank, however, faced a summary indictment, a spokesman with a local public prosecutors office told AFP, meaning he was expected to be fined but exempted from standing trial.

Prosecutors decided to impose the lighter penalty on him considering his retirement to take responsibility for the scandal, Jiji Press said.

The indictment came nearly a month after he stepped down, apologising for the embarrassment caused by a violent outburst in October that left countryman Takanoiwa with a fractured skull.

"I'm truly sorry for hurting Takanoiwa mentally and physically," Harumafuji told police, according to Jiji Press.

Harumafuji's exit mirrors that of another Mongolian star, Asashoryu, who stepped down in 2010 after being accused of breaking a man's nose in a drunken brawl outside a Tokyo nightclub.

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, 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 fight, which broke out at a bar in the western Japanese city of Tottori in late October, according to local media.

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

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 drug 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.

The 135-kilo (298-pound) Harumafuji, whose nifty technique makes up for his relative lack of size, won nine Emperor's Cups before his fall from grace.

Source: AFP