Tokyo  - The former master of a Japanese sumo wrestling stable was sentenced to six years in prison Friday over the physical abuse of a teenage trainee in 2007 which led to the boy's death, media reports said.

Junichi Yamamoto, 59, was held to be responsible for three senior wrestlers physically abusing 17-year-old sumo trainee Takashi Saito at his Tokitsukaze stable.

Yamamoto ordered the three to force Saito into sparring exercises after the teenager tried to run away from the stable, the court said.

The three wrestlers who were involved in the abuse already received suspended prison terms and were dismissed by the Japan Sumo Association after they were found guilty by the Nagoya District Court.

The court heard that Yamamoto hit Saito with a beer bottle during a dinner in June 2007 and ordered the other three wrestlers to beat the junior member with a wooden stick.

Saito was smashed onto the ring and beaten with a metal bat by the wrestlers during a 30-minute sparring session the next day and later died from multiple trauma injuries at hospital.

Yamamoto, who was also dismissed by the sumo association, immediately filed an appeal against Friday's ruling. His lawyers argued that the three wrestlers had acted on their own and that sparring was a regular training practice.

Traditional sumo training is known to involve severe physical disciplines to foster the feeling of perseverance.

Yamamoto apologized to Saito's family during the trial but denied he ordered the assault.(dpa)