Stay Gold's father is American Horse of the Year and Triple Crown contender Sunday Silence.

Oju Chosan's mother is Shadow Silhouette, sired by two-time Japanese Horse of the Year Symboli Kris S. Oju Chosan made his debut at the Tokyo Racecourse under the training of Mitsuhiro Ogata in October 2013 in a flat race but finished in 11th place and his second race in 8th place,[7] before a broken front leg forced him to take a year off, by which point maiden races that suited Oju Chosan had finished.

[8] Training role was soon passed from Ogata to Shoichirō Wada soon after, with Shinichi Ishigami being his primary jockey.

[6] Oju Chosan's victory at the Nakayama Grand Jump in 2022 made him the oldest horse in Japan to win a graded race, as well as the most wins in a JRA G1 steeplechase races.

[8] Oju Chosan retired in December 2022 after finishing in 6th place at the 2022 Nakayama Daishogai behind Nishino Daisy.