Deep Impact, by Sunday Silence, is considered the best racehorse in Japanese horse racing history.

Deep Impact won the 2005 Satsuki Sho (Japanese 2000 Guineas) in Nakayama by two and a half lengths from outsider Six Sense, despite having stumbled at the start. It was his fourth start.

He then won the Tokyo Yushun (the Japanese Derby over 2400m) and the Kikuka Sho (the Japanese St. Leger Stakes over 3000m in Kyoto), becoming the first horse since Narita Brian in 1995 to complete the Japanese Triple Crown. Deep Impact also became the first unbeaten Japanese Triple Crown winner since Symboli Rudolf in 1985.

In his next race, the Arimakinen, Deep Impact was defeated by Hearts Cry.

In 2006 Deep Impact won the Tenno Sho and the Takarazuka Memorial. He had won 10 of 11 starts in Japan.

In October 2006, he started favourite in the Prix de l'Arc de Triomphe in Paris, but finished third and later tested positive for a banned substance, Ipratropium.

Japanese Triple Crown winner and superstar Deep Impact then scored an emphatic win in the 2006 Japan Cup with a superb victory in Tokyo.

Deep Impact, racing in front of 113,552 racegoers, won by two lengths from Dream Passport, with globetrotting mare Ouija Board a further half a length back in third.

Deep Impact, ridden by Yutaka Take, was cruising in the rear for a large part of the race as Cosmo Bulk led them along. Take asked Deep Impact to move up just before they turned into the straight and Japan’s favourite horse went around the leaders, was briefly bumped, quickly got into overdrive and then simply galloped to victory with an outstandingly composed performance worthy of a superstar.

Ouija Board was closing on Dream Passport at the post but there was no doubt about the quality of the race and the victor.

The great Deep Impact was retired on Christmas Eve after a three length victory in the Arima Kinen at Nakayama. Deep Impact beat a quality field including Melbourne Cup runner up Pop Rock, who was second, with Melbourne Cup winner Delta Blues in sixth. As usual Yutaka Take kept Deep Impact near the rear as Admire Main took the lead. Deep Impact went to the front near the final bend and galloped to victory as he had done in the Japan Cup. The field also included Daiwa Major, who was third.

With victory in the Arima Kinen, Deep Impact became only the third Japanese horse to win seven Group 1 races.