Bulgarian Kotooshu overpowered Iwakiyama on Monday to remain undefeated and in sole possession of the lead at the Autumn Grand Sumo Tournament.
Kotooshu came charging out of the blocks at Tokyo's Ryogoku Kokugikan and forced No. 4 maegashira Iwakiyama to the edge of the ring where he used an arm throw to send his opponent out.
Sekiwake Kotooshu improved to 9-0 while Iwakiyama dropped to 4-5.
In the day's final bout, grand champion Asashoryu of Mongolia stayed one win off the pace at 8-1 when he got a grip of compatriot Kyokushuzan's belt after the faceoff and calmly lifted the No. 4 maegashira over the ridge.
Asashoryu is gunning for his sixth straight Emperor's Cup and 14th overall. Kyokushuzan, who was unable to mount any challenge against the yokozuna grappler, dropped to 4-5.
Lower-ranked wrestler Kisenosato defeated rank-and-filer Kotonowaka earlier and also stands at 8-1.
In other major bouts, ozeki Chiyotaikai used his trademark arm thrusts to send fan favorite Takamisakari out over the straw ridge.
Chiyotaikai, who needs a winning record in this tournament to maintain his ozeki status, improved to 6-3 while No. 5 maegashira Takamisakari dropped to 3-6.
Ozeki Tochiazuma got a grip of Futeno's belt and shoved the komusubi grappler out to improve to 7-2.
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