The following are the events in professional sumo during 2018. Tournaments Hatsu basho Ryōgoku Kokugikan, Tokyo, 14 January – 28 January Haru basho Osaka Prefectural Gymnasium, Osaka, 11 March – 25 March Natsu basho Ryōgoku Kokugikan, Tokyo, 13 May – 27 May Nagoya basho Aichi Prefectural Gymnasium, Nagoya, 8 July – 22 July Aki basho Ryōgoku Kokugikan, Tokyo, 9 September – 23 September Kyushu basho Fukuoka Kokusai Center, Kyushu, 11 November – 25 November News January 6: The highest ranked referee, Shikimori Inosuke, is reported in the Japanese media to have apologized for sexually harassing a junior referee in a hotel in Okinawa Prefecture on December 16 last year, while drunk. 9: The three current yokozuna, Hakuhō, Kakuryū and Kisenosato, perform the traditional New Year dohyo-iri ceremony at the Meiji Shrine. 14: The Sumo Association suspend Shikimori Inosuke for three tournaments. He has already submitted his resignation, but it will not take effect until after the suspension ends in May 2018. With the other top referee title (Kimura Shonosuke) currently vacant, this will be the first time since the March 1994 tournament that neither of the head referees (tate-gyōji) will be available. 11: Kakuryū and Kisenosato, both of whom have missed some or all of the preceding four tournaments, each confirm that they will enter the forthcoming Hatsu basho. 22: Egyptian juryo division wrestler Ōsunaarashi withdraws from the tournament after reports emerge that he was involved in a rear-end motor collision at the Yamanouchi, Nagano ski resort town on January 3. Osunaarashi apparently defied the Sumo Association's ban on wrestlers driving cars, and also did not have a valid licence. He initially told police that his pregnant wife was driving and he switched seats to protect her, but back-tracked when confronted with security video evidence. 25: A lawsuit against Kasugano Oyakata and a former member of Kasugano stable who had been convicted of assault, is publicly revealed for the first time. The victim, another former wrestler from the stable, alleges that Kasugano failed to prevent the attack and delayed medical treatment. 27: The championship is won by maegashira Tochinoshin, who defeats Shōhōzan to move to an unassailable two-win lead of 13 wins against just one loss. It is the first championship by a maegashira since Kyokutenhō in 2012. 28: On the final day of the Hatsu Basho, Tochinoshin wins again to finish on 14–1, two wins ahead of ōzeki Takayasu