Equinox is a Japanese thoroughbred by Kitasan Black out of Chateau Blanche by King Halo trained by Tetsuya Kimura. His dam Chateau Blanche is the G3 Mermaid Stakes winner at Hanshin. Equinox finished his 2-year-old season with two wins from two starts. In three-year old season, he won the Tenno Sho (Autumn) and Arima Kinen (The Grand Prix), and he remains unbeaten for four-year-old campaign with four G1 titles including Longines Dubai Sheema Classic, Takarazuka Kinen, Tenno Sho (Autumn), and Japan Cup. He secured the top spot with a rating of 129 for his performance in the Dubai Sheema Classic and became the third Japanese horse to top the rankings after Just A Way in 2014 and A Shin Hikari in 2016.
He is also a winner of the 2022 Japanese Horse of the Year awarded by Japan Racing Association. His major wins are 2022,2023 G1 Tenno Sho (Autumn), 2022 Arima Kinen (The Grand Prix), 2023 G1 Longines Dubai Sheema Classic, 2023 Takarazuka Kinen, and 2023 Japan Cup.