It’s a brilliant rule, heightening the drama within the sport and the sport within the drama, and it’s a rule that not only cost Bondi Beach the St Leger but also robbed Jack Hobbs of the Derby, Storm The Stars the Irish Derby and Kingfisher the Gold Cup.

The rule allowing horses to be supplemented for big races at late stages, at a premium price, has been the catalytic converter for taking this season from middle-lane mediocrity to fast-lane fascination.

The supplement supplant has been the move of the year, the buy-in/take-out blueprint that has added generic value to the race and intrinsic value to the successful schemer, Simple Verse at Doncaster (via High Holborn), Trip To Paris at Royal Ascot, Jack Hobbs at the Curragh and, in the Derby itself, Golden Horn, who will likewise have to pay his way into the Arc, incidentally.

Curvy (Ribblesdale) and Covert Love (Irish Oaks) are two other flavoured additives of 2015, instances which perfectly illustrate the necessity of the supplementary option, as, in the course of the season, the driving force of both fillies broke their SatNav, demanding a new and improved destination, mutually beneficial for horse and race.

But Golden Horn and Jack Hobbs are the supplementary princes, orchestrated by the supplementary king, and the universal king for that matter, John Gosden, who moves his pieces around the thoroughbred board like a Grandmaster.

Nathaniel in the 2011 King George and Great Heavens in the 2012 Irish Oaks are previous works of ancillary art by Grandmaster Gosden, whose veil of assurance masks his astute adaptability.

Nurturing a horse beyond its foreseeable means is one thing, but having the convictional courage to play the supplementary game is quite another, and Gosden follows the John F. Kennedy line that "change is the law of life, and those who look only to the past or present are certain to miss the future."

In the past, Gosden has been fairly adamant that Shalaa is a sprinter through and through, already pencilled in for the Commonwealth Cup in 2016, while in the present Shalaa will strut his sensational stuff once again in the Middle Park Stakes at Newmarket on Saturday, that race completely at his mercy. But might he miss out in future by galloping down his pre-determined path?

If, as could happen, the temptation increases over the winter to aim a little higher, and stretch a little further, with the three-year-old Shalaa then his current price for the Guineas will look big. Very big.

True, the Guineas looks a more dangerous jungle now than a fortnight ago, after the game of anything you can do I can do better between Emotionless and Air Force Blue on successive days on racing’s epic weekend, but they only came up to Shalaa’s level, merely jumping the same ratings height that he’d already soared over, not once but twice.

Though speedy, electrically so, Shalaa isn’t headstrong, never looking to be flat out at the end of his races, and there’s a lot in his pedigree to suggest he’d stay the trip of the Guineas. Last year, Kingman and Charm Spirit won a phenomenal seven European Group 1 mile events between them, both by Invincible Spirit, the same sire as Shalaa.

Shalaa is the fifth foal of Ghurra, who has produced two hurdling winners, Pearl Castle and Dai Bando, albeit both by Montjeu, but Ghurra herself, having kept to sprinting as a juvenile, ran her best race over nine furlongs aged three.

And then there are the three ‘p’s: pressure, prestige and promotion, all interlinked in a way. Let’s presume – and the odds as well as the ratings say it’s okay to do so – that Shalaa waltzes away with the Middle Park, then he’ll have already won two Group 1s over six furlongs, and there might, just might, be an added pressure to try for the greater prestige of the Guineas over a mile, for his future promotion as not a highly-marketable sprint sire but a highly-marketable sire full stop.

It’s purely a hypothetical dot-joining exercise, but the dots are there, pretty significant ones at that, and just as the risk/reward of a Guineas tilt is in Shalaa’s favour, and maybe even his interest, the same goes for ante-post punters, too.

Thinking that far ahead may be foolish, but it’s worth remembering that, at this time last year, Golden Horn and Jack Hobbs were mere dots on a dice yet to be rolled by Gosden.