TOKYO (AFP) - A sumo wrestler and his stable master have been ordered to pay more than $287,000 (S$392,000) to a fellow grappler for daily abuse which led to loss of sight in one of the man's eyes, news reports said.

Tales of extreme physical abuse are becoming more common in sumo - the Japanese national sport - characterised by harsh training and strict hierarchy, and also rocked in recent years by bout-fixing rumours and illegal gambling.

The Tokyo District Court in its ruling said that Yasushi Aoki, the head of the Shibatayama stable, and a senior wrestler should pay 32.4 million yen (S$392,000) in compensation to the plaintiff, who had demanded 68.9 million yen in the civil trial, Jiji Press reported.

The victim, whose name was not reported, joined the stable in 2008 and suffered "daily abuse" including beatings from senior wrestlers, according to the ruling.

The court said that he underwent surgery four times for a detached retina due to the abuse but lost sight in his left eye in 2013, according to the Yomiuri Shimbun daily. The court declined to confirm the reports.

The wrestler had also sued the Japan Sumo Association, but the court did not order it to pay any of the damages.

Aoki, a former grand champion, said it was an "unfair ruling" and that he planned to appeal, Jiji said.

Last year a former Japanese sumo stable master admitted to abusing an assistant, including beating him with a bat, stuffing a towel in his mouth and forcing him to eat a full container of wasabi, the notoriously hot Japanese condiment.

In 2007, a 17-year-old sumo apprentice died after a hazing incident involving his stable master and senior wrestlers.

The stable master, who struck the teen with a beer bottle, was sentenced to five years in jail for negligence resulting in death.