Shinzo was foaled and raised at Coolmore and is by dual Group 1 winning mare Samaready.

Samaready was bought by Coolmore in 2020 for $1.8million at the Inglis Chairman's Sale when she was carrying Shinzo in utero.

[2] Shinzo made his race debut on 25 January 2023 in the Canonbury Stakes when finishing in third position.

This victory assured the horse a start in the Golden Slipper just seven days later.

It also gave Waller the final leg of Australian racing's “Grand-Slam” having won the big 4 races; the Melbourne Cup, the Caulfield Cup, Cox Plate and the Golden Slipper.