The PGAChampionship is a mystery in so many ways. The final major of the year begins Thursday at Kiawah Island along the coastal waters of South Carolina, a golf course that has not been in the spotlight since it punished some of the best players in the world in the 1991 Ryder Cup.

Still fresh are the images of Mark Calcavecchia losing a big lead under the pressure from a big event and a relentless course, and Hale Irwin shooting a 41 on the back nine and still winning the decisive match. But that was more than 20 years ago.

Jose Maria Olazabal, now the European captain, is the only player from that Ryder Cup who is playing in the PGA Championship. There are 15 other players who have taken on the Ocean Course over the years at two World Cups, a list that includes Padraig Harrington, Jim Furyk, Angel Cabrera and K.J. Choi.

For everyone else, no one is sure what to expect on a Pete Dye design that is 7,676 yards, the longest in major championship history. Tiger Woods, Adam Scott and Graeme McDowell played Kiawah a week before the PGA Championship to get an idea what they face.

“I walked off the front nine saying, ‘This course is not all that.’ I walked off the back nine and said, ‘Yeah, it’s good. It’s good,’” Mc- Dowell said. “It’s a course of two nines. The front nine has no real definition to it. The back nine has a bit of elevation, a bit of water. It’s good.”

That’s only part of the mystery.

The majors have rarely been this unpredictable, especially when it comes to the final round.

It started with the Masters, when Bubba Watson came from three shots behind and won in a playoff. Then, Webb Simpson rallied from four shots back on the last day to win the U.S. Open. Still, nothing was more stunning than the British Open, when Ernie Els started the final round six shots back— and was still four behind with three to play — and won whenAdam Scott bogeyed his last four holes.

Not since 1989 have all four majors been won by players who were not in the lead going into Sunday.

“It’s showing how deep the fields are and that winning from the front is tough,” Luke Donald said. “I think that’s why we all respect what Tiger has done in the game, because he was so good at getting a lead and keeping it. That’s a tough thing to do. And obviously, that’s been shown this year that no lead is really safe.”

Woods used tomake it look so easy. Fourteen times he had at least a share of the lead going into the final round of a major. Fourteen times he posed with the trophy. But since winning his last major, the 2008 U.S. Open at Torrey Pines, only four players in the last 17 majors have held onto the lead on Sunday.

“I think everybody got spoiled with Tiger winning,” Brandt Snedeker said. “I bet if you look back 20 years ago, very few guys closed all the time. Tiger was the best closer ever. But you know, it’s hard to win. Guys are getting nervous. Guys behind don’t get nervous, they just fire at pins because you’re not thinking about it.”

Perhaps that will change at Kiawah. Then again, it was only a year ago at Atlanta Athletic Club when Keegan Bradley walked off the 15th hole of the final round in the PGA Championship trailing by five shots. He wound up with the Wanamaker Trophy.

Go figure.