Kōbōyama Daizō (born 15 August 1957 as Kōkichi Yomogida) is a former sumo wrestler from Tsukidate, Kurihara, Miyagi Prefecture, Japan.

He reached the top makuuchi division for the first time in November 1981, although he was demoted back to juryo after three tournaments.

In November 1983 he won his second Technique prize and was promoted all the way from maegashira 7 to sekiwake, because of the failure of the men above him in the rankings to obtain winning records.

[2] He won only two bouts in this tournament and made the sanyaku ranks only one more time, at komusubi in September 1985.

Koboyama served regularly as the tsuyuharai to Chiyonofuji for the yokozuna's dohyo-iri ceremony, even though the two were not members of the same stable or ichimon.

Takashima ran for a seat on the Sumo Association's board of directors in January 2016, but was unsuccessful.

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