Many times a pro's 501 leg looks like this: 100, 140, 100, a good try (or the brilliant shotout) on the remaining 161, or scores of 140, 100, 140 for 121 left. Anyway, to throw a good leg a score of at least 100 is a necessity.
Then you are playing, and your start in 501 is brilliant - 100 first turn, 140 second turn. You are on 261, and you have seen the pros playing another ton to 161 and shooting this out for a fabulous 12 darter, or even another ton-forty for a nice 'standard' 121 finish. Or you have thrown two 100s, and now from 301 you would have a chance for the 12-darter with 140 or 180, while a 'solid' 100 (or even 60) would still keep you on course for a pretty good leg, with a good chance for 15 or 18 darts.
You take a breath, step up to the oche and throw 45 - &"%$!
When you get to your next 501 tournament or league night watch the players of whom you know they are good but still lack some experience compared to the top players. Look for legs where they start good with two nice turns, and see what the third turn brings. In many cases you will find them throwing poor exactly here.
The interesting phenomenon is that the better your first two turns where, the more crucial is the third turn becoming, and the higher is the probability that inexperienced players fail there. The reason for this is explained above - it's 501 maths, you will rarely see it in cricket or other games. What happens is that your third throw has been put under pressure. Not from your opponent (who is likely to be well behind at this moment), but from yourself! You see the possibility of playing a good leg, and of course you want that 12,15 or 18-darter. After your first throw of 100 you don't think too much of the good leg yet (it's more like 'ey, good start'), but with your second throw of ton or ton-plus the possibility lies directly in front of you, and this raises the pressure (with 'wow, got a chance here, now I must take it!' on your mind; by the way, this problem is also very similiar to bad throws after a maximum 180!).
To handle the situation the most important thing is to keep cool. I'm sure you have already experienced this 3rd turn problem, but maybe you haven't yet been aware that it exists and that it is a common one (you should be now, and this already is the key point for defeating it). It's quite the same problem as every pressure situation - and if you are a frequent reader of The Dart Thrower you know how to fight pressure (if you are not, read the previous articles, especially the one about 'tension'). It is, like always, a matter of the right htinking. Don't have the 12 or 15 darts on your mind. I know, most of my readers don't throw such legs too often, and many will still have to throw their first 12-darter in 501, but don't worry about that -sooner or later they will come when you are a solid practiser. Don't chicken out when the chance is there, stay as cool as possible. When you face the third round problem, think like this: My opponent is well behind (which he usually is; if he is not, then the typical third round problem doesn't appear, because you are already under 'normal' pressure from your opponent and don't have the 'brain time' for other thinking!), and I can play this leg home when I throw just normal solid darts. Concentrate on simply playing the leg, not on playing it brilliant. You did nothing else in the first two rounds, right? So there is no need to change a winning 'team' (or better, a winning mental state). You know solid 60 will most probably do, so why should you chicken out? Another handy trick is to throw your last dart on the T19 when you have already scored two single 20s. You will have a finish for the great leg with a 97 score, too, so going away from the 60 may reduce pressure (the third dart is most likely to slip to 5 or 1 when aimed on the 60 with too desperate desire).
The third turn problem is also very suitable for visualizing exercises (again, if you have never heard of this mental technique before explore the 'previous articles' section). Remember your own experiences and feelings when you have failed in this situation and work on them. Together with using your knowledge on how to handle pressure situations in matchplay you will be able to become a perfect 'master of the third turn'!
Karlheinz Zöchling, Vienna, 28 April, 1998