was an American-bred Japanese-trained Thoroughbred racehorse and sire. In a racing career which lasted from 1997 until 2000 he won nine of his fifteen races including four Grade I races. He was the leading juvenile colt in Japan in 1997 when he was unbeaten in four races, culminating in a victory in the Asahi Hai Sansai Stakes. He missed most of his second season with injury problems but returned in autumn to win the Arima Kinen. He reached his peak as a four-year-old when he won the Takarazuka Kinen and a second Arima Kinen. He failed to win in three races in 2000 and was retired to stud. He had some success as a breeding stallion.

Background Grass Wonder was a chestnut horse with a white star, standing 15.3½ hands high bred in Kentucky by Phillips Racing Partnership & John Phillips, of the Darby Dan Farm. He was sired by Silver Hawk, an American-bred colt who finished third in the 1982 Epsom Derby and later became a successful breeding stallion, siring the 1997 Epsom Derby winner Benny the Dip, the 1999 St Leger winner Mutafaweq and the leading American turf performer Hawkster. Grass Wonder's dam Ameriflora was an unraced daughter of Danzig. She was a great-granddaughter of Soaring, an American broodmare who was the ancestor of many major winners including Glorious Song, Saint Ballado, Rahy and Singspiel.

The yearling was consigned to the Keeneland sale in September 1996 and was bought for $250,000 by Nobuo Tsunoda. Grass Wonder auction history Grass Wonder was exported to Japan where he was trained by Mitsuhiro Ogata and was mainly ridden in his races by Hitoshi Matoba.

Racing career

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.

Despite his lack of form in 1998, Grass Wonder was one of sixteen horses selected to run in the Arima Kinen over 2500 metres at Nakayama on 27 December. His opponents included Air Groove (Tenno Sho (autumn)), Matikanefukukitaru (Kikuka Sho), Mejiro Bright (Tenno Sho (spring)), Mejiro Dober (Shuka Sho, Queen Elizabeth II Commemorative Cup), Offside Trap (Tenno Sho (autumn)), Seiun Sky (Satsuki Sho, Kikuka Sho), Silk Justice (Defending Champion), Stay Gold and Yusei Top Run. Grass Wonder won by half a length from Mejiro Bright with a gap of two and a half lengths back to Stay Gold who took third place ahead of Seiun Sky.

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. On 26 December at Nakayama, Grass Wonder attempted to become the fourth horse following Speed Symboli, Symboli Rudolf and Oguri Cap to win back-to-back runnings of the Arima Kinen, and the sixth horse following Ryu Forel, Shinzan, Speed Symboli Inari One and Mejiro Palmer to win both of Japan's all-star Grand Prix races in the same year, the other being the Takarazuka Kinen. His main opponents in the fourteen runner field included Mejiro Bright, Narita Top Road, Phalaenopsis, Special Week, Stay Gold, Symboli Indy (NHK Mile Cup) and T. M. Opera O (Satsuki Sho). The race produced a dramatic finish with the lead changing hand several times in the last 200 metres, but Grass Wonder prevailed by a nose and a neck from Special Week and T. M. Opera O with Tsurumaru Tsuyoshi half a length away in fourth.

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 The following racing form is based on information available on JBIS Search and netkeiba.com

DateDistance (Condition)RaceClassCourseFieldHNOdds(Favored)FinishTimeWinning(Losing)MarginJockeyWinner(2nd Place)Ref1997 – two-year-old season Sep 13 Turf 1800 m (Firm) Two Year Old Debut Nakayama 10 9 1.5 (1) 1:52.4 3 lengths Hitoshi Matoba (Bildschon) Oct 12 Turf 1400 m (Firm) Ivy Stakes OP Tokyo 9 8 1.4 (1) 1:21.9 5 lengths Hitoshi Matoba (Machikane Sanshiro) Nov 8 Turf 1400 m (Firm) Keisei Hai Sansai Stakes GII Tokyo 9 2 1.1 (1) 1:21.9 6 lengths Hitoshi Matoba (Machikane Sanshiro) Dec 7 Turf 1600 m (Firm) Asahi Hai Sansai Stakes GI Nakayama 15 11 1.3 (1) lengths Hitoshi Matoba (Meiner Love) 1998 – three-year-old season Oct 11 Turf 1800 m (Firm) Mainichi Okan GII Tokyo 9 6 3.7 (2) 5th 1:46.4 ( lengths) Hitoshi Matoba Silence Suzuka Nov 7 Turf 2500 m (Firm) Copa Republica Argentina GII Tokyo 18 13 3.0 (1) 6th 2:33.5 ( lengths) Hitoshi Matoba Yusei Top Run Dec 27 Turf 2500 m (Firm) Arima Kinen GI Nakayama 16 2 14.5 (4) 2:32.1 length Hitoshi Matoba (Mejiro Bright) 1999 – four-year-old season May 15 Turf 1400 m (Firm) Keio Hai Spring Cup GII Tokyo 18 5 2.1 (1) 1:20.5 length Hitoshi Matoba (Air Jihad) Jun 13 Turf 1600 m (Firm) Yasuda Kinen GI Tokyo 14 7 1.3 (1) 1:33.3 (nose) Hitoshi Matoba Air Jihad Jul 11 Turf 2200 m (Firm) Takarazuka Kinen GI Hanshin 12 5 2.8 (2) 2:12.1 3 lengths Hitoshi Matoba (Special Week) Oct 10 Turf 1800 m (Firm) Mainichi Okan GII Tokyo 10 8 1.2 (1) 1:45.8 nose Hitoshi Matoba (Meisho Odo) Dec 26 Turf 2500 m (Firm) Arima Kinen GI Nakayama 14 7 2.8 (1) 2:37.2 nose Hitoshi Matoba (Special Week) 2000 – five-year-old season Mar 26 Turf 2500 m (Firm) Nikkei Sho GII Nakayama 10 7 1.3 (1) 6th 2:36.3 (6 lengths) Hitoshi Matoba Leo Ryuho May 14 Turf 1400 m (Firm) Keio Hai Spring Cup GII Tokyo 18 8 2.4 (1) 9th 1:21.6 ( lengths) Hitoshi Matoba Stinger Jun 25 Turf 2200 m (Firm) Takarazuka Kinen GI Hanshin 11 11 2.8 (2) 6th 2:14.7 ( lengths) Masayoshi Ebina T. M. Opera O

on the time indicates that this was a record time

Retirement and stud record

Grass Wonder was retired from racing to stand at the Shadai Stallion Station in Hokkaido. He later moved to the Breeders' Stallion Station where he was based in 2015.

Notable progeny c = colt, f = filly, g = gelding

bold: GI/JpnI grade winners

+Grade winnersFoaledNameSexMajor Wins2002FeliciafFairy Stakes2002Maruka RascalcNakayama Grand Jump, Nakayama Daishogai2002Osumi Grass OnecNiigata Daishoten (2x)2003Meiner ScherzicKyoto Kimpai, New Zealand Trophy2003Sakura Mega WondercRadio Tampa Hai Nisai Stakes, Naruo Kinen (2x), Kinko Sho2004Meiner RainiercKeio Hai Nisai Stakes, Swan Stakes2004Screen HerocCopa Republica Argentina, Japan Cup2005EarnestlycChunichi Shimbun Hai, Kinko Sho, Sapporo Kinen, Sankei Sho All Comers, Takarazuka Kinen2006Seiun WondercNiigata Nisai Stakes, Epsom Cup, Asahi Hai Futurity Stakes2007Cosmo HelenoscStayers Stakes2007Meisho KampakucKyoto Daishoten2008Big RomancecZen-Nippon Nisai Yushun2008Shigeru JuyakucNiigata Jump Stakes, Hanshin Spring Jump2010Smart OriongOcean Stakes, Chukyo Kinen

Death Grass Wonder died at Big Red Farm on 8 August 2025, after suffering multiple organ failures linked to old age. He was 30.

In popular culture An anthropomorphized version of Grass Wonder appears as a character in the Japanese multimedia franchise Umamusume: Pretty Derby, voiced by Rena Maeda. She is depicted as a calm and gentle North American exchange student who aspires to become the ideal Yamato nadeshiko. She has a deep fascination for Japanese culture, which can be seen by her wielding a naginata in the mobile game adaptation. However, her graceful and friendly facade hides an aggressive, no-nonsense, and highly competitive nature. Her in-game career mode and role in the anime series take inspiration from her real-life counterpart's racing career, such as her rivalry with Special Week and comparisons to her upperclassman Maruzensky. Phillips was unfamiliar with Umamusume, whereas Maeda is a horse racing fan who visited the real Grass Wonder in 2018.

Pedigree

References