Tesco Boy was foaled in 1963. He was owned by
Sir Jack Cohen, the founder of
Tesco, who named the horse after the supermarket chain. At the end of 1967, he was exported to Japan to stand stud at the Hidaka Light Stallion Agricultural Cooperative's Monbestu Stud Farm in the
Hokkaido region. In Japan, Tesco Boy saw massive success as a sire and became a major part of the Japanese horse racing bloodline. In six different years, Tesco Boy was the
leading sire in Japan and his offspring would win nearly all of Japan's major races. Included among his most notable progeny are
Kitano Kachidoki,
Tosho Boy,
Tesco Gaby, and
Hagino Kamui O, all of whom won major races that would later be considered Grade 1 when grading was introduced to horse racing.
Tosho Boy himself also became a successful sire after his racing career. As a broodmare sire, Tesco Boy was also highly successful, with his daughters producing such successful race horses as
Ines Fujin, the 1990
Tōkyō Yūshun winner,
Trot Thunder, the 1996
Yasuda Kinen and
Mile Championship winner, and
Nehai Caesar, the 1994 Autumn
Tenno Sho winner. He is also the grandsire of
Mr. C. B., who won the Japanese Triple Crown in 1983. Another of Tesco Boy's grandsons,
Sakura Bakushin O, became a successful sire in his own right, and Tesco Boy's bloodline continues in the 21st century mainly through descendants of Sakura Bakushin O. This includes
Kitasan Black, of whom Sakura Bakushin O is the damsire of. Tesco Boy died on 25 October 1987, aged 24. ==Notable progeny==