Mile Championship
Harbinger was retired in 2011 to the Shadai Stallion Station in Japan. In the autumn of 2017 he had his first Grade 1 winners when his three-year-old daughters Deirdre and Mozu Katchan won the Shuka Sho and the Queen Elizabeth II Cup respectively before the colt Persian Knight took the Mile Championship. His fourth Grade 1 followed in 2018 when Blast Onepiece won the Arima Kinen. Deirdre gave Harbinger a European Group 1 win in August 2019 when taking the Nassau Stakes.