Kagamiō Hideoki (Japanese: 鏡桜 秀興, born 9 February 1988 as Batkhuu Nanjid (Mongolian: Батхүүгийн Нанжид)) is a former Mongolian-born professional sumo wrestler from Ulaanbaatar.

He took the shikona Kagamiō Nanji (鏡桜 南二), the surname taken from part of his stable's name and the given name because it sounds similar to his real given name of Nanjid.

Though he did manage to get a majority of wins in his first tournament, his continuing low weight of around 90 kilograms was one factor holding him back and he struggled in the jonidan division for close to two years.

This was not a satisfactory situation for training, so Kagamiō would often commute to the now defunct Nakamura stable to get adequate practice with other wrestlers.

In September 2013, future ōzeki and fellow Mongolian Terunofuji beat him on the final day to force a subsequent playoff between them.

[5] Regardless of this, one more solid performance at 10–5 in the jūryō 1 rank would garner him promotion to the top flight makuuchi division for the January 2014 tournament.

Kagamiō was the first wrestler from Kagamiyama stable to make the top division since his coach took control of it seventeen years previously.

[7] In an interview about his promotion, talking about his lengthy rise, he happily joked, "for me it felt quite quick, I thought it was going to take me 15 years."

However, in the following May tournament, at jūryō 9 he posted an impressive 12–3 record, beating Hidenoumi on the last day to avoid a playoff, and finally taking the championship on his third chance.

Continuing injury problems saw him pull out of five successive tournaments between July 2020 and March 2021 and fall from makushita to the jonidan division.

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