The G1 Prix de l’Arc de Triomphe (2400m) never fails to excite but rarely have race fans and racing analysts looked in so many different directions as they attempt to solve the riddle of Sunday’s (2 October) great Longchamp spectacle.

Intriguing Arc debates include questions such as: Can Germany’s Torquator Tasso consolidate on his 72/1 shock win of last year? Can one of the four Japanese contenders – among the 20 equine stars declared on Thursday (29 September) – end the thwarting of their long-held aspiration to capture Europe’s great 2400m Group 1 in Paris? Can the Newmarket-trained grey galloping machine Alpinista gain her sixth consecutive Group 1 win under Luke Morris, or can either Luxembourg, Vadeni, Onesto, Al Hakeem, Bubble Gift or Mendocino give their respective jockeys Ryan Moore, Christophe Soumillon, Stephane Pasquier, Cristian Demuro, Olivier Peslier and Rene Piechulek yet another experience of just how good it feels to win the Prix de l’Arc de Triomphe?

And, of course, 51-year-old Frankie Dettori – booked for Torquator Tasso – has won the Arc a remarkable six times and, while he won’t be celebrating gate 18, he will be more than delighted in the latest predictions of a soft – possibly even heavy – Longchamp surface on Sunday.

On Tuesday (27 September), Dettori flew to Germany to partner Torquator Tasso in work at the Mulheim stable of trainer Marcel Weiss who commented: "It was really important Frankie came. Not only was there a real harmony between horse and rider but I wanted to see ‘Tasso’ again travel around a right-handed track. He feels like a different horse that way."

Weiss then described the nightmare of his narrow defeat in his Arc preparation – albeit a Group 1 preparation – in this month’s four-runner G1 Grosser Preis von Baden (2400m).

"The race was as good as decided soon after the start when there was no pace and no chance of getting any cover for him,” he said.

Weiss says he is more nervous this year with his five-year-old horse being one of the Arc favourites rather than last year when the horse was an unconsidered outsider. And the trainer added: "The trouble with the Arc is that once you’ve won it you want to do it again. You get greedy!"

His narrow conqueror at Baden-Baden was Mendocino, ironically ridden by Piechulek who had achieved that sudden fame on Torquator Tasso last year, but has a contract to ride Mendocino, who also happens to be trained by Piechulek’s partner Sarah Steinberg. 

The trainer said: "Like Torquator Tasso, Mendocino likes soft ground but he can get stressed and will have ear plugs again in Paris, as he had in Baden-Baden. We are expecting a big run."

Four-year-old chestnut colt Mendocino will be an outsider but, along with last year’s winner, German-trained horses are often underestimated in the Arc as those who can remember Danedream’s win in 2011 or Star Appeal’s 118/1 victory in 1975 would confirm.

Interestingly, Piechulek considers that another outsider – the Andre Fabre-trained Mare Australis (Bauyrzhan Murzabayev) – is possibly his biggest threat.

Japan’s main hope in righting its Arc hoodoo – which consists of four seconds, one third and 22 unplaced returns – probably rests on the shoulders of the fearsome front-runner Titleholder (Kazuo Yokoyama), who arrives here after successive Japanese Group 1 wins over contrasting trips of 3200m and 2200m, the latter victory in course record time.

But 53-year-old superstar Yutaka Take warns against ignoring Do Deuce who he rode to win the G1 Japanese Derby (2400m) at Tokyo in May before being beaten into fourth when favourite for his Arc trial in the G2 Prix Niel (2400m) at Longchamp this month. Take said: "Do Deuce was still in his Arc preparation phase in the Prix Neil and just got tired late on. We still think that he is the right horse for this race."