He came to Japan in 2000 with an invitation to try out for Tatsunami stable through a connection with Kyokutenhō's contemporary Kyokushūzan, and entered sumo in March, 2001, the same tournament as the later Mongolian yokozuna Hakuhō.

The ring name he took combined "Mōko" (猛虎, "fierce tiger", which is homophonous with the old Sino-Japanese name for Mongolia, 蒙古) with the "nami" of Tatsunami stable.

Possibly challenged by debuting at such a high rank, Mōkonami's first two tournaments in the top division were losing performances.

However, in the November 2009 tournament, he finally achieved a positive record of 9–6 at the 13th maegashira slot, staving off any fears of demotion from makuuchi.

After clinching his kachi-koshi on the final day of the July 2010 tournament, he reached a new highest rank of maegashira 6 in September.

After an investigation by the Sumo Association into allegations of bout-rigging prompted by the discovery of text-messages on a mobile phone belonging to former maegashira Kasuganishiki, Mōkonami was one of 23 wrestlers and coaches found guilty of involvement.

Sanshō key: F=Fighting spirit; O=Outstanding performance; T=Technique     Also shown: ★=Kinboshi; P=Playoff(s) Divisions: Makuuchi — Jūryō — Makushita — Sandanme — Jonidan — Jonokuchi