NEW YORK — The Triple Crown.

Three races in a five-week span at varying distances on different tracks. So tough only 11 horses have won it, none in 34 years, by far the longest gap ever.

Now it's your turn to try, I'll Have Another, on Saturday at the Belmont Stakes.

"You need the racing luck," suggests Bob Baffert, the only trainer to lose the Belmont three times with horses that won the first two legs.

It's tougher these days because of changes in breeding, full fields of 20 horses in the Kentucky Derby, more foals and an increased emphasis by owners and trainers on the sport's three biggest races.

I'll Have Another, an average-sized chestnut colt, appears to have rebounded well after two hard races in the Derby and Preakness, with the most exhausting still to come. He'll run 11/2 miles around Belmont's oval with 11 rivals gunning to keep history from happening.

Before Affirmed swept the 1978 Kentucky Derby, Preakness and Belmont, 25 years had passed between Citation in 1948 and Secretariat in 1973.

Ask trainers and jockeys what makes winning the Triple Crown so difficult, and no one can agree on a single factor.

Real Quiet had no luck in 1998, when a nose separated him from racing immortality. The year before, Baffert watched from the stands as Silver Charm lost by three-quarters of a length. In 2002, War Emblem nearly fell to his knees when the starting gate sprang open, and Baffert knew right then the colt was doomed. He straggled home in eighth place, beaten 191/2 lengths by a 70-1 shot.

"Everybody is trying to take their little shot at you," Baffert said.

When Sir Barton became the first horse to sweep the Kentucky Derby, Preakness and Belmont in 1919, the phrase Triple Crown hadn't been invented. And he wasn't even the most popular horse of his era; that mantle belonged to Man o' War, who won nine of his 10 starts as a 2-year-old but didn't run in the Derby the next year.