Rory McIlroy has played Carnoustie, site of the 147th Open Championship, quite a few times in his career. Obviously he's only played it as an Open venue one time -- he was low amateur in 2007 -- but this track is one of the three used in the European Tour's fall Dunhill Links tournament, which McIlroy plays often.

He discussed its unique nature recently.

"How difficult Carnoustie is as a golf course," McIlroy said. "It's probably one of the most well-bunkered golf courses in the world in terms of position and making you think and giving you options off the tees."

However, the Carnoustie that McIlroy normally plays (even at The Open in 2007) is a far different Carnoustie than the one that will be played at this Open. Green is now brown. "Firm and fast" is now "hard as a rock and an absolute speedway." So how will players attack a course that has seen a 330-yard 3-iron and 430-yard drive so far? 

"You'll see guys playing this golf course very differently," 2017 champion Jordan Spieth said Monday before fully checking out the course conditions. "You'll see a lot of different strategies."

"It certainly plays into the hands of guys who can thread the ball around," said Padraig Harrington, the 2007 Open champ at this course. "The great thing about this golf course, or the interesting thing, is you can't take all the trouble out. There's no perfect strategy that eliminates risk. You're going to have to take some risk. You're going to have to ... skirt by some bunkers. It's very difficult to stay short."

The dry, speedy conditions might make that even more difficult.

"Eventually, you're going to have to grow up and hit the shots," Harrington added. "You're going to have to take some chances. I'm not sure there's a strategy that you can set out right now that you could stick to on every hole without waiting to see how the weather changes, the wind changes, how the scoring happens. 

"I think the most important thing is every player is going to have to be fluid when it comes to their strategy, that they're not going to be able to set out a strategy that they could stick to at all times. They're going to have to be able to adapt, watch their playing partner, see what they do, and learn as they go along."

That's fascinating, isn't it? It makes for the most ambiguous event of the year in which if you told me right now any one of about 35 guys was crowned champion at the end of the week, I would believe it.

"It is a completely different course," said course record holder Tommy Fleetwood, who shot 63 here last year during the Dunhill Links. "I played yesterday, just I've never played it this firm or fast. Shots that you've hit have literally no relevance for a lot of it. It was definitely apparent that the difficulties this week are probably going to be putting it in play and hitting it in the fairways and go from there.

"The greens are still pretty receptive. You can tuck some pins away, but overall the greens are pretty flat. It doesn't do any harm to have played it for a few years. It doesn't do any harm to have a course record, but it's a completely different challenge to what we normally face."

Solving that puzzle -- an Open Championship puzzle at the trickiest track with unknowable conditions that offer myriad solutions -- is going to make this tournament good. Who and how many golfers actually figure it out are what could make it great.