Zenno Rob Roy waltzed away with Japanese Horse of the Year honors last year with a late-season sweep of the Autumn Tenno Sho, the Japan Cup, and the Arima Kinen. On Sunday at Tokyo Racecourse, he will embark on an attempted repeat of that remarkable triple in the $2.2 million Autumn Tenno Sho, a 1 1/4-mile Grade 1 turf contest that has attracted a field of 18 runners.