Grass Wonder (Japanese: グラスワンダー, Hepburn: Gurasu Wandā; 18 February 1995 – 8 August 2025) was an American-bred Japanese-trained Thoroughbredracehorse 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 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.
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.
Mitsuhiro Ogata, who trained Grass Wonder throughout his racing career
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
R on the time indicates that this was a record time
Retirement and stud record
Grass Wonder in retirement, 2002
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.
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 career mode in the video game and role in the anime 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
Pedigree of Grass Wonder (USA), chestnut stallion, 1995
12Suda, Takao (July 2017). スマートなライバルと比べて 泥臭い存在として大レースを制覇[A foreign-bred horse that won the Arima Kinen twice in a row Fused with Grass Wonder]. 優駿 WEB (in Japanese). Retrieved 31 August 2026.
↑Cygames. Umamusume: Pretty Derby. Scene: Grass Wonder – Career.Level/area: The Beast's Successor. Reporter A: 'That's why people started calling her the Beast in the first place... But now, Grass Wonder has entered the picture!' / Symboli Rudolf: '...Hmm.' / Reporter A: 'She's already this strong, and she hasn't even debuted yet! Heck, she hasn't even been scouted yet! [...] She's right up there with Maruzensky! I think the Beast's Successor would be the perfect nickname for her!'
