Sadanoyama Shinmatsu

was a Japanese professional sumo wrestler from Nagasaki Prefecture. He was the sport's 50th yokozuna. After his retirement he was the head coach of Dewanoumi stable and served as head of the Japan Sumo Association.

Career Born in Arikawa, Minamimatsuura District, he made his professional debut in January 1956, and reached sekitori status four years later upon promotion to the jūryō division in March 1960. He made his top makuuchi division debut in January 1961. Sadanoyama won his first tournament title in only his third tournament in the top division, from the rank of maegashira 13. The achievement of winning a tournament from the maegashira ranks is sometimes seen as a jinx on subsequent success in sumo, but Sadanoyama disproved that theory by going on to reach ōzeki in March 1962 after winning his second title, and then yokozuna in January 1965 after capturing his third championship.

He made a cameo appearance in the 1967 James Bond film You Only Live Twice, as himself. Although more attention was focused on yokozuna Taihō and Kashiwado, with their rivalry referred to as the Hakuho era after a combination of their shikona, Sadanoyama in fact ended up winning more tournament championships than Kashiwado. In 1995, he also abrogated the tour system, changed from a promotional performance to an association independent performance.

He changed his toshiyori name to Sakaigawa in 1996, handing over the Dewanoumi name and the day-to-day running of his stable to the former Washūyama. The same year he tried to pass a new reform allowing the association to be the sole administrator of kabu to face the rising speculation around the possession of titles. At the time, the titles were either transmitted within a family or bought from the previous owner, the reform aimed to make the kabu the exclusive possession of the association the latter now giving the titles to the people requesting them. The proposition was however met with a refusal from the board of the association.

He did not run for re-election in 1998, after it became clear he lacked enough support due to his failed reform. He was then succeeded by former ōzeki Yutakayama from the rival Tokitsukaze faction. Remaining on the board, he subsequently became head of the judging department, an unusual move for a former head of the Sumo Association. Sadanoyama declined his right of doing a Kanreki dohyō-iri after receiving his red tsuna, in the form of taking responsibility for the turmoil during his time as a chairman. He stood down as an elder in 2003 upon reaching the mandatory retirement age of sixty five