Tactically and strategically, the Old Course is one of the most entertaining golf venues in the world.
The first time you play it, you'll probably hate it. You'll hit a good one and then catch a bunker, or fire it straight at the pin and not even find it.
But once you get to know your way round it's brilliant.
The Old Course will welcome the Open for the 28th time
It's totally unique and you're stimulated all the way around to keep it in the right spot. That's what keeps you mentally on your toes.
It helps to have a calculating chess-type mind to know when you're going to take risks, what flags you can get at, when is it folly to go for the pin and when do you just play for par and walk on?
It's a permanently interesting test, which challenges every single shot in the book, and some that have not been invented yet.
You have to be able to play a wide range of strokes, and do it consistently, often in fairly unpleasant conditions.
Some of its - maybe we should say her - aura stems from the fact that a lot of the bunkers are unsighted, so you can't see them from the tee, which adds to the mystery.
And there are so many different ways of getting the ball from A to B.
It's dependent on wind and pin positions but every shot has different possibilities and there are lots of playable options.
Generally, both going out and coming back, the further left you are off the tee, the safer it is, but harder to get close to the pins.
The more I studied the Old Course, the more I loved it. And the more I loved it, the more I studied it
Legendary golfer Bobby Jones
And the tighter to the right you go, the closer you are to the out-of-bounds, though you have a better angle into the flag.
But with every shot you face, there are myriad ways of playing it. Do you go low, high, run it, chip it, play a draw or a fade?
There's no right way, and it's wonderful for "feel" players and imaginative shot making. Most modern golf is played in the air - you can see where you are going, you hit it between the bunkers and then onto the green.
But St Andrews brings a whole new dynamic to the game. It's no longer a case of just hitting, say, a simple nine iron. Maybe you've got to run it through a little hollow or whatever.
It's very stimulating, and that's without the wind. It can differ in strength and direction constantly.
Montgomerie plays out of the Road Hole bunker at St Andrews
The first nine can play downwind with the homeward nine back into it, or vice-versa, or both can play downwind or upwind or a combination, so the exam paper is permanently changing. It's true that some holes are defenceless without any wind, but that's true of any links course.
There's also that beautiful links turf that will go white and rock hard in a warm week.
But the key is to plot your way round avoiding the 112 bunkers, as Tiger Woods did for the whole week when he won in 2000.
Some of the names of these traps, such as Hell and The Coffins, invoke fear before you've even got there.
Many are deep pots with steep, riveted faces which make you wonder, not "can I get a four-wood to it, but can I even get out?"
Another quirk is that all the double greens add up to 18 when you combine their holes, so for example 5 is with 13, 11 & 7 and 10 & 8
BBC golf commentator Peter Alliss
Hitting the ball a long way does give you an advantage, as long as you're not in a bunker, as you'll have a more lofted club for your second.
But the second shot is progressively more difficult the further off line you go.
The huge putting surfaces and double greens on 14 of the holes also present problems, with a variety of possible pin positions and plenty of 40-foot putts leaving longish ones still for par.
And finally there's the history. St Andrews is steeped in it, and winners of the Open over the Old Course read like a who's who of the world's greatest-ever players.
Winning a major is tough, winning the Open for a European is harder still with all the home pressure and for a British or Irish player, winning the Open at St Andrews is like the Holy Grail.
St Andrews is unique and the fact that it has been sacred to change for nigh on a century makes you feel like you are still walking in the footsteps of Open champions from 100 years ago.