Japan and Circus Maximus give Aidan O'Brien a strong hand as he goes in search of a record-equalling sixth victory in the Juddmonte International at York on Wednesday.

It is 19 years since the Ballydoyle maestro first landed the Group One prize with the mighty Giant's Causeway (2000) - and he has since added to his tally with Duke Of Marmalade (2008), Rip Van Winkle (2010), Declaration Of War (2013) and Australia (2014).

This year's two contenders have both done well since running in the Investec Derby, in which Japan finished third and Circus Maximus sixth.

Japan has subsequently landed the King Edward VII Stakes at Royal Ascot and the Grand Prix de Paris at Paris Longchamp, while Circus Maximus successfully dropped back to a mile in the St James's Palace Stakes before pushing Too Darn Hot all the way in the Sussex Stakes at Goodwood.

O'Brien said: "We've been happy with Japan since France, and he seems to be in good form.

"We're obviously bringing him back to a mile and a quarter - and we think the experience will do him good back at this trip.

"Circus Maximus is going up in trip and he ran a very good race at Goodwood last time.

"The stiff mile in Ascot suited him,and then he still ran very well on the easy mile at Goodwood. We always felt a mile and a quarter would suit him well. He seems to be in good form since he ran."

The John Gosden-trained King Of Comedy looked every inch a top-class prospect in the making when winning the Heron Stakes at Sandown on his penultimate start - and did nothing to suggest otherwise when beaten a diminishing neck by Circus Maximus at the Royal meeting.

Connections are looking forward to seeing him step up to a mile and a quarter for the first time on the Knavesmire, but are well aware of the task ahead - with O'Brien's pair and Michael Stoute's proven top-notcher Crystal Ocean among King Of Comedy's rivals.

An impressive course-and-distance success in last month's York Stakes prompted connections of the Mark Johnston-trained Elarqam to stump up the required £75,000 to add him to the International field.

A son of Frankel out of the Middleham trainer's former star mare Attraction, Elarqam has long been held in the highest regard.

Stoute's second string Regal Reality, Japanese raider Cheval Grand, David Menuisier's outsider Thundering Blue and David O'Meara's Lord Glitters complete the nine-strong field.

The  latter won the Queen Anne at Royal Ascot in June before finishing fifth in the Sussex Stakes and will step back up in trip for another leg of the Qipco British Champions Series.