Sue Montgomery: Vision D'Etat can defy Aga's dynasty and inflict Arc defeat on Zarkava

The threads that bind the sport, and make it more than merely an opportunity to bet in the instant, are very much part of this weekend's tapestry. Take the raging hot Prix de l'Arc de Triomphe favourite Zarkava, for instance. Her story, with reference to the here and now, began 86 years ago. On 14 September, 1922, the third Aga Khan, spiritual leader of the Ismaili Muslims and friend of European aristocracy, acquired a grey yearling filly at the auction sales in Doncaster for 9,100 guineas.

Named Mumtaz Mahal, she repaid her new owner's outlay – the equivalent of nearly £400,000 today – by becoming a turf legend. On 14 September this year Zarkava, her seven-greats grand-daughter, staked her claim for similar immortality by winning the Prix Vermeille over the course and distance of tomorrow's 87th running of the Arc. Zarkava was bred by and runs in the colours of the present Aga Khan, the old man's grandson. Among the racehorses he inherited in 1960 when his father, Aly Khan, died young in a car crash was another belle ideal of the track, Mumtaz Mahal's direct descendant Petite Etoile. But though she was a great racemare, she was a disaster as a progenitrix. Her dynasty hung on her last baby, the sole daughter she produced from just three surviving offspring. The Aga Khan named the foal Zahra, after his own daughter, then aged four. The filly grew up the opposite of her dam: a useless racehorse and a great broodmare, two-greats grandmother of Zarkava.

Little Princess Zahra grew up as a chip off the old block in her love and understanding of horses. This afternoon at Newmarket, the pride of her own nascent breeding programme, Darjina, will contest the Sun Chariot Stakes, one of nine Group One prizes over a glittering two days in England and France.

The Qatar-sponsored Arc, the world's richest race on turf with its €4m (£3.1m)purse, is the centrepiece. And something will have to give at Longchamp. Zarkava takes to the fray an unbeaten record. And so does the perceived second-best of the home defence, her three-year-old contemporary Vision D'Etat. If, as the Aga Khan has said, the breeding business is a game of chess with nature, then success tomorrow for Vision D'Etat would be check-mate against a grandmaster. The colt was meant to be a jumper; he is a half-brother, out of a four-times hurdles winner, to chaser Milan Deux Mille, who took this year's Grand National field along for a circuit.

The man who produced him, Gilles Gaetan, also bred, among others, the Cheltenham Gold Cup runner-up Exotic Dancer. Sent to market as a yearling, the son of unproven Chichicastenango was bought by provincial trainer Eric Libaud for just €39,000 (some £30,000) and runs in the colours of Jacques Detre, who owned Azertyuiop in his early days.

But for the slenderest of cords, Zarkava might not have existed. But for the workings of fate, Vision D'Etat's life might have been so different. The underbidder for him at auction was one of Britain's leading jumping agents, David Minton. "He was a lovely individual, a real Cheltenham prospect," he recalled, "but I had my limit. His sire was unknown and it would have been hard to sell him on."

Grand Prix de Paris winner Chichicastenango, out of a one-eyed mare whose best performance was to win a claimer, thoroughly outran his pedigree. Vision D'Etat has followed suit, graduating from performances in the provinces to take the Prix du Jockey-Club and, last month, the most significant Arc trial, the Prix Niel.

Zarkava has some hefty pages of history to overturn tomorrow, but the last of her age and sex to take an Arc, Akiyda, did carry the same famous green colours, back in 1982. The daughter of sprinter Zamindar may yet prove herself a wonder horse, but neither her draw, tight on the inside of the 16-strong field, nor the ever-softening ground at Longchamp are wholly in her favour.

Any rain, however, will suit Vision D'Etat. "He has natural speed, but I've never had a doubt about his stamina," said Libaud, who has a stable of 60 at Le Lude, 150 miles south-west of Paris. "He's improved since the Niel and he's a really happy horse." To add piquancy to the clash between the unbeaten pair, Libaud used to be assistant to Zarkava's trainer, Alain de Royer-Dupré.

The highest-rated horse in tomorrow's field, and indeed on turf in the world, is Duke Of Marmalade, but his connections have made no secret of the fact that he will not run if the ground deteriorates markedly, and further soaking for the marroniers in the Bois de Boulogne is forecast today and tonight. Yesterday the four-year-old drifted like the Marie Celeste on the betting exchanges in favour of his Aidan O'Brien stablemate Soldier Of Fortune.

At around 9-1, Vision D'Etat is the value. Today at Newmarket Darjina (3.15) can become the bride after five successive runner-up spots. And in the Cambridgeshire, one of those races that does provide fun for punters, Huzzah (3.50) can raise a cheer.

Bushranger puts Wachman on Classic landscape

Aidan O'Brien has three chances today to add to 20 Group One victories this season, first at Longchamp with Astronomer Royal and US Ranger in the Prix de la Foret and with the peerless Yeats in the Prix du Cadran, and then at Newmarket with Halfway To Heaven and Listen in the Sun Chariot Stakes. Yesterday his employers at Coolmore carried on their plunder without him, with Bushranger in the Middle Park Stakes.

The colt was the third top-level victory of the campaign for David Wachman, after his own Prix Morny and Again's Moyglare Stud Stakes. Driven out by Johnny Murtagh, the 15-8 favourite saw off Sayif readily but, given the the ordinary record of the Newmarket race as a Classic pointer, the market for next year's 2,000 Guineas barely rippled.

In the equivalent filly contest, the Cheveley Park Stakes, there was a welcome return to the top table for local man Rae Guest, with Serious Attitude, a duckling who became a swan. When offered as a yearling, the Mtoto filly failed to find a buyer, and was afterwards passed to Guest for the equivalent of buttons. She is now unbeaten, a Group One winner, and as short as 10-1 for the 1,000 Guineas.