 Oso was interested in sumo from a young age, as his father was the director of the Ibaraki Prefecture sumo association.He won national amateur titles at high school and at Senshu University, where he was a rival of Tosanoumi.He made his professional debut in January 1993 in the third "makushita" division, as due to his amateur achievements he had been given "makushita tsukedashi" status.