Asashoryu returned to Mongolia in 2007 due to a stress disorder.
Mongolian sumo champion Asashoryu has announced his retirement following allegations he attacked a man outside a Tokyo nightclub last month.
"I feel heavy responsibility that I have caused trouble to so many people, Asashoryu said.
The wrestler's stable master said he could not remember what happened on the night because he was too drunk.
Asashoryu, the first Mongolian to become champion, has been described as the "bad boy" of sumo for his conduct.
He is alleged to have attacked the man during an argument in Nishiazabu, an expensive nightclub area in Tokyo.
Asashoryu made his debut in 1999 and rose quickly through the ranks, attaining top-level yokozuna, or grand champion, status four years later.
Sumo traditionalists have accused Asashoryu, whose real name is Dolgorsuren Dagvadorj, of being too brash for a grand champion.
In 2007 he was suspended - the first such move in the history of sumo wrestling - for missing a training tournament. Following the incident, he returned to Mongolia to seek treatment for a stress disorder.