The last time Ryan Moore weighed out at 117 pounds in the United Kingdom was on June 9, 2006, when the superstar rider finished second aboard a galloper trained by his father, Gary, at Brighton.

Determined to ride Warm Heart in Sunday’s Group One Longines Hong Kong Vase (2,400m), Moore will attempt to wind back the years and make the feather weight for the HK$24 million contest, although Jockey Club stewards have approved him to weigh out up to two pounds over.

“She’s a light weight, but I rode a horse at Santa Anita carrying eight stone seven [119 pounds]. This will be lighter, but we’ll do what we can,” Moore said. “I think she’s a nice chance, but there’s a couple of good unexposed Japanese horses in there.”

Warm Heart has enjoyed a busy campaign, triumphing in five of her eight assignments this year, and will aim to go one better than her last-start second in the Group One Breeders’ Cup Filly & Mare Turf (2,000m).

Aidan O’Brien has travelled to Hong Kong on the hunt for a fourth Vase victory and admitted he was surprised Moore had agreed to take the ride on his three-year-old filly.

“Since Ryan came to us, I don’t think I’ve ever seen him do that [weight],” O’Brien said. “He straight away wanted to make sure he was able to do the weight on her, so hopefully, she can run a good race.

“We think she’s well in at the weights, and she ran a great race in America and just got nabbed late. She’s a hardy filly, and she should love the track and ground.”

“She’s very fresh, and physically she’s doing great. I think if we had run her in the Irish Champion Stakes, she might have just been behind the first two.”

If Warm Heart completes a successful raid on the Hong Kong Vase, it could be her last appearance, with O’Brien suggesting the daughter of Galileo may head to the breeding barn.

“It could [be her last start],” O’Brien said. “She would suit Justify, so there’s a good chance she could go to him after.”

O’Brien boasts representatives in all four of Sunday’s feature contests, with three-time Group One winner Luxembourg locking horns with Romantic Warrior in the Group One Hong Kong Cup (2,000m).

Moore will reunite with the four-year-old after opting to ride the eventual winner, Auguste Rodin, in September’s Group One Irish Champion Stakes (2,000m), with Luxembourg giving a good account to finish second.

“I haven’t ridden him for a while, but I think he goes there with a very solid chance,” Moore said. “Romantic Warrior is very hard to beat, and with the likes of Prognosis, it’s always a very hard race. I think he should get a decent shot at it.”

An intended runner in the Group One British Champion Stakes (2,000m), Luxembourg’s untimely foot bruise forced him to miss that assignment.

“The injury held up him up for two weeks, and this was always going to be his next target after that,” O’Brien said. “He loves nice ground, and everyone is very happy with him.”

Completing O’Brien’s four-strong attack on Sha Tin’s marquee meeting are Aesop’s Fables in the Group One Hong Kong Sprint (1,200m) and Cairo in the Group One Hong Kong Mile. Moore will partner all the Ballydoyle master’s runners, but he has not accepted any other rides.