1997: two-year-old season Grass Wonder began his racing by defeating nine opponents in a
maiden race over 1800 metres at
Nakayama Racecourse on 13 September 1997. A month later he followed up in the Ivy Stakes over 1400 metres at
Tokyo Racecourse, winning from Machikane Sanshiro. In November he was moved up in class for the
Grade II Keisei Hai Sansai Stakes over the same course and distance and won from Machikane Sanshiro and Courir Cyclone. On his final start of the season, Grass Wonder was one of fifteen colts to contest Japan's most prestigious race for juveniles, the Asahi Hai Sansai Stakes over 1600 metres at Nakayama on 7 December. Ridden by Matoba, he won by two and a half lengths from Meiner Love (later to win the
Sprinters Stakes) who took second ahead of Figaro and
Agnes World. Grass Wonder was voted
Japanese Champion 2-Year-Old Colt of 1997 at the
JRA Awards.
1998: three-year-old season As a foreign-bred horse, Grass Wonder was not eligible to race in many of the major Japanese races for three-year-olds, and when he sustained a leg injury in March 1998 it was decided to reserve him for an autumn campaign. He made his first appearance of the year he finished fifth behind
Silence Suzuka in the Grade II
Mainichi Okan over 1800 metres at Tokyo in October. In the following month he was moved up in distance for the Grade II Copa Republica Argentina over 2500 metres at Tokyo and finished sixth behind
Yusei Top Run.
1999: four-year-old season Grass Wonder began his third season in the Grade II Keio Hai Spring Cup over 1400 metres at Tokyo on 15 May. He won by three quarters of a length from Air Jihad, to whom he was conceding four pounds. The unplaced horses included Phalaenopsis (
Oka Sho,
Shuka Sho) and the
Godolphin challenger
Lend A Hand (
Gran Criterium). On 13 June over 1600 metres Grass Wonder faced Air Jihad at level weights in the
Yasuda Kinen. He was beaten a nose by his rival with the pair finishing two and a half lengths clear of
Seeking The Pearl (
Prix Maurice de Gheest) in third place. Grass Wonder returned to middle distances for the Takarazuka Kinen over 2200 metres at
Hanshin Racecourse on 11 July and was matched for the first time against
Special Week, a colt who had won the
Tokyo Yushun in 1998 and the spring edition of the
Tenno Sho. The other runners included Matikanefukukitaru and Stay Gold. Grass Wonder defeated Special Week with a gap of seven lengths back to Stay Gold in third. After a break of almost three months, Grass Wonder returned for the Grade II Mainichi Okan over 1800 metres at Tokyo on 10 October and won from Meisho Odo and Embrasser Moi. For his efforts over the course of the season, Grass Wonder was given a special award at the
JRA Awards for 1999.
2000: five-year-old season Grass Wonder remained in training as a five-year-old colt but failed to reproduce his best form. He finished sixth behind Leo Ryuho in the Grade II Nikkei Sho over 2500 metres at Nakayama on 26 March and then ran unplaced behind the filly Stinger in the Keio Hai Spring Cup. In his final race the horse ran for the second time in the Takarazuka Kinen and finished sixth of the eleven runners behind T. M. Opera O. ==Racing form==