John Size has called on champion jockey Ryan Moore to ride Ping Hai Star in the BMW Hong Kong Derby but the bigger surprise is that the horse will trial at Happy Valley just nine days out from the HK$18 million classic and six days after his last run.

With regular rider Joao Moreira committed to ride Ping Hai Star’s stablemate Nothingilikemore in the Derby, Moore was considered the most likely candidate to ride Size’s in-form four-year-old.

Size confirmed Moore’s booking on Thursday and also that Ping Hai Star would head across town for a hit-out on Friday.

Ping Hai Star will trial over 1,700m with Moreira aboard in preparation for a first try at the Derby distance of 2,000m.

Size has trialled Ping Hai Star at Happy Valley before his last three wins but each time over 1,200m and none have been this soon after a race or as close to his next run.

“He hasn’t had a race over the Derby distance in his life and I think the trial at Happy Valley and the timing of it might suit him,” Size said.

Ping Hai Star is by 2008 Australian Derby winner and stamina-laden sire Nom Du Jeu, which suggests that he won’t have a problem running a strong 2,000m, but Size has expressed concerns about the gelding’s inexperience up in trip.

After two defeats at a mile, Ping Hai Star rattled off three straight wins over 1,400m to rise 26 points in the ratings and into Derby contention.

There was some speculation Size would use the trial as a chance to run without blinkers but the master trainer said the horse’s normal race-day gear would remain intact.

“He has won all of his races in blinkers, so we won’t be changing anything,” Size said.

Moore is considered by most to be the best jockey in the world and has formed a strong association with Size from limited opportunities during short-term stints and one-day visits.

The 34-year-old Englishman has notched five wins from 17 starts for Size at an impressive strike rate of 29 per cent, including wins in the first two legs on the four-year-old series in 2016 aboard Sun Jewellery.

Moore was unplaced in the 2016 Derby on Sun Jewellery but was second a year earlier aboard outsider Got Fly.

Tough sprinter Blizzard will also trial before jetting out for Japan next week to contest the Group One Takamatsunomiya Kinen on March 25 at Chukyo.

John Size’s Ping Hai Star adds X-factor to a strong 2018 Hong Kong Derby field

“He leaves Hong Kong on March 12 and we just wanted him to have one more workout before he gets on the plane as it has been six weeks since his last run,” said trainer Ricky Yiu Poon-fai.

In other news, Jockey Club officials have confirmed that incoming apprentice Victor Wong Chun will be indentured to trainer Tony Millard.

Wong has already ridden 119 winners in Australia with the 24-year-old’s most recent stint based in Adelaide with trainer Richard Jolly.