Grand champion Harumafuji D.Byambadorj has decided to retire as a sumo wrestler to take responsibility for his assault on a lower-ranked wrestler, his stablemaster Isegahama said Wednesday.

Isegahama is expected to file the Mongolian yokozuna’s letter of resignation with the Japan Sumo Association later in the day.

D.Byambadorj has caused great trouble to the association and the public, Isegahama said, adding the yokozuna bears grave responsibility.

Harumafuji has admitted to assaulting his compatriot Takanoiwa in a drinking event at a restaurant-bar in the western Japan city of Tottori during a regional tour late October.