Of all the elements that make up a links course, and particularly a British links course, none is quite so distinctive as the bunkering.
On inland courses, bunkers can sometimes seem almost decorative, but links bunkers are at the heart of what The Open Championship is all about. The player who wins at Royal St George's this week will either be very good at getting out of them, or very good at not getting into them. Preferably both.
Links bunkers have a severity that the sand traps on parkland courses rarely match. Put your ball in a greenside bunker on a parkland course and you can often be pretty confident of getting up and down in two; do the same thing on a quality links course and you can send your score skywards.
How many Opens have been lost in the Road Hole bunker at St Andrews? How many times each day does Thomas Bjorn recall the trap by the 16th at Royal St George's where his chance of the 2003 title evaporated?
Tony Jacklin's Open victory at Lytham in 1969 was built squarely on his talent for recovery shots from the Lancashire course's hazards. Tiger Woods' momentous win at St Andrews in 2000 came down to the skill with which he kept his ball safely away from the sand. Of course, any Open champion needs an all-round game, but his bunker play must be pin-sharp for four days.
Royal St George's capriciousness tends to divide opinions among top players, but I've always liked it. It tends to play the hardest and fastest of all the Open courses, so you need a certain equanimity to deal with what it dishes up. It's a place where you have to shrug, bite your lip, grimace and get on with it. And if that's not what golf is all about, then what is?
As a general rule, an Open champion will play well from greenside bunkers and avoid the fairway traps completely. With the kind of devious kicks off the fairways you can expect at Royal St George's, that can be hard to do, but the player who picks up the Claret Jug on Sunday will have done better than most of his rivals in both regards.
And, just as the topography of Sandwich causes problems, so does the sand itself. At Royal St George's it somehow seems more powdery, drier and dustier than at other Open venues, and it can be hard to judge shots with real precision.
All links bunkers have a depth and profile that makes them hard to tackle. You might be able to escape, but can you land your ball in the precise corner of the green where you want it? Do you dare to play a six-iron from a fairway bunker when you know your ball may clatter against the lip and land back at your feet? Such thoughts will crowd in on the players this week.
Let the bunker busting begin.
This one sits in a very strategic position in the crook of the dogleg. With wind behind it's not really a problem, but in any other conditions it preys on players' minds. It's pretty deep, so almost impossible to reach the green in two if your ball goes in. Many players end up in the right-side rough as they try to avoid it.
The most famous at Sandwich, this massive, steeply-angled trap dominates the view from the tee. Put your ball in this and you're in serious trouble, as a succession of players have found out. It looks vicious and nasty - and it is. Players who go left to play safe often land in another little trap that's invisible from the tee. Greenside bunker.
The second shot at this par four is semi-blind. Approaching the green, the last place you want to find your ball is in the front-left bunker. With a generous pin position it is maybe not so bad, but on other days it can be almost impossible to get to within 10 feet of the flag from this brutal little trap. Three fairway bunkers. Bad luck come in threes on this hole.
To get a decent approach to the green you have to go left with your tee shot, but these three little horrors lie in wait for any poorly struck drives. The difficulty of the challenge they present is very wind dependent, but the players have to take them on.
This is the one where Thomas Bjorn's Open fell apart eight years ago. The 16th green is circled by sand traps, but this one is the worst because of the way it gathers the ball. Recovery - as Bjorn found out - can be very hard, for with a pin on the left you have to punch your shot into the bank and judge the weight to perfection.