This article originally appeared in the March 2001 issue of GammOnLine.|
Thank you to Kit Woolsey for his kind permission to reproduce it here.
A long time ago I was having a conversation with Paul Magriel about the
causes for errors. He said something which surprised me -- that for
all players (even experts), the most common cause of error isn't choosing
the wrong alternative between candidate plays but not seeing the best play
as a candidate in the first place.
This surprised me. Surely experts are capable of finding all the decent alternatives one would think. However, upon upon analysis of matches it became clear that Magriel was quite correct. The biggest blunders came because the best move simply hadn't been considered. Sometimes it was a complete oversight. Sometimes the player was simply concentrating on the wrong theme and didn't see the best move because it involved a different theme than he was working on.
Here are a few examples from top-level competition in important matches.
Obviously Ballard should play 7/3(3), 4/0. However he blanked out and played 7/4(3), 6/2, unnecessarily leaving a shot. What happened? Probably when Ballard saw the 4-4 number and realized that he had to use three of the fours to bring the men in, he was convinced that his play was forced and that he had to leave a shot. He overlooked that once the checkers were in he could take a man off with the fourth four.
Obviously Goulding should play 11/8, 10/8, locking up the full prime and virtually claiming the game and the match. Instead he played 7/2, exposing himself to a 6-1 joker. What happened? He was so focused on covering the blot on the two point with a five that when he saw the 3-2 roll he immediately grabbed a checker from the bar point to cover. Of course he knew that making the full prime is correct -- he just didn't see it.
Here is my personal worst blunder (at least the worst that I know about -- it wouldn't surprise me if there were worse ones out there which I never realized I had made).
A great roll, entering with the six and hitting with the four. But I blanked out and never saw it. I played B/15. I'm sure that what happened was that I was concentrating on entering, and when I saw the four on one of the dice I came in with the four and looked for a six to play.
Both Ballard and Goulding survived. Senkiewicz missed the shot, and Ballard brought the position home. Dwek didn't roll the 1-6 joker, and Goulding completed the prime next roll and went on to win. I wasn't so fortunate. Kissane went on to gammon me, taking over the lead. It was a huge turning point in the match, both from the score and psychologically (yes, I realized my error just after I had made it). If I had hit I might well have been the favorite particularly since I owned the cube -- it would have certainly been close at worst. I eventually lost a close match, so while we will never know what would have happened it is safe to say that my blunder quite likely cost me the match.
If this sort of thing can happen to the best players in the world, what about the average player? As you can guess, it happens to him much more. We will all have oversights, but we want to cut down on them as much as possible. What can we do in this area?
The most important thing, of course, is to examine all the reasonable alternatives. This means to find them first. Not too difficult, you say. After all there are only a finite number of legal plays for any position and roll, and many of them can be properly dismissed immediately as ridiculous. So why do players at any level not see the best move as a candidate? There are many reasons.
One of the most common errors is to be overly focused on a particular number. When that number comes up, you may play it immediately on one of the dice and then look around for how to play the other part of the roll. The problem with this is that there may be an entirely different and superior play which doesn't involve playing the number the way you had planned. Here is a very simple example from the early part of the game.
Before rolling, Blue is praying for an ace or a six so he can hit the blot on the bar point. Upon seeing the 6-3 roll, it is very tempting to immediately hit with the six and then decide whether to play 24/21 or 13/10 with the three. After all, that is the six that Blue was looking for. Of course, the correct play by far is none of the above -- it is 24/15*. This gains in the race, rips away White's builder, starts to escape a back checker, and leaves fewer return shots. The average player is well aware of this, but if he makes the mistake of playing the six first by hitting he may never even see the correct play as a candidate. It should be noted that had he chosen the play the three first and played 24/21 and then looked for the best six, he would have had no difficulty finding the right play.
How can this sort of trap be avoided? One very good rule is to never play part of your roll until you have examined all the candidates and are convinced that the part of the roll you are playing is definitely among all of the alternatives you are considering. Had I not made the error of entering with the four and then looking for the best six in the previous position where I blundered, I probably would not have overlooked the hit.
It should be noted that if you are convinced about half of your play, then it is a good idea to play the part you are sure of. For example, if you are on the bar and have rolled a 6-4, you might as well play the four first and then think about the six. Or if your opponent has hit loose on his five point early in the game and you enter with a 5-3, you know quite well that you are going to hit the blot, so you should play the five, hitting, and then look for the best three. This helps you visualize the resulting positions better. However, you must be absolutely sure about the part of the move you know you want to make. Some positions can be deceptive.
Blue is going full force for his five point. Before he rolls he can see he hits on the five point with aces, twos, and fives. When the 5-3 appears it is very easy for him to instantly play 10/5* and then try to decide between 13/10 and 23/20 for the three. Of course, the correct play is none of the above -- it is 13/8*, 8/5*. However if Blue plays the wrong five first, he will never even see the correct play.
The problem of never seeing the corect play is very common when you have rolled doubles. Once again it is quite easy to be blindsided into making a play which does something you wish to accomplish without seeing all the alternatives.
Blue is eyeing his five point, the point he wants to make the most. This is his big chance with the 1-1. He instantly plays 7/6, 6/5 with three of the aces and then starts looking for the best way to play the fourth ace. All fine and good, but Blue hasn't considered all the possibilities. Making the five point is strong, but it isn't forced. After Blue makes the five point White has twos to anchor, sixes to escape one checker, and several rolls which are an improvement on White's side of the board. If Blue looks at all the alternatives, he will see that 4/3(2)*, 2/1(2)* is very strong. This puts two White checkers on the bar against a three-point board, and Blue has sufficient ammunition in place to hope to carry out a blitz. I believe this blitzing play is better than making the five point. If Blue considers the blitzing play and rejects it in favor of making the five point that is okay -- just a matter of judgment. However if Blue never even considers the blitzing play, that is a serious error.
What can be done to make sure you examine all the candidate plays? There are no sure-fire answers to this, but there are several steps you can take which will help you to find all the reasonable possibilities.
1) Look for all the moves. I don't mean examine every legal possibility -- that would be silly. Also it is quite easy to dismiss most of the legal plays at a glance. If you have three checkers on your six point in the early stages of the game and you roll 4-3, you know you aren't going to be playing 6/3, 6/2, so that sort of play can be eliminated quickly. However, do note where each checker can go for each die. Checkers aren't necessarily planted in one place, even if it is good point. Following that philosophy would have protected me in this position I had recently:
I made the natural looking play of 23/14. The proper playof 8/5*, 8/2 never even crossed my mind. Why did I miss it? Because in my mind the checkers on the eight point point were pinned down there, and I didn't want to move them. I could see that running the back checker was generally something I wanted to do. So when the 6-3 appeared I immediately played 23/14. Had I taken the time to see where all my checkers played with a six and a three, it is likely I would have found the correct play.
2) Keep in focus. When you have rolled a very good or a very bad number, it is very easy to lose concentration and let your emotions take over. Don't fall for this trap. Regardless of the position and dice roll, analyze every candidate rationally and make sure you have found them all. Witness this horror show I had recently.
I had just rolled a joker the previous roll, and now I was correctly playing on for a gammon. The 5-5 was a horror roll of all time, and I was completely flustered. It looked hopeless, and I finally wound up playing 8/3(2), 7/2(2) leaving a bunch of shots. The correct play of 8/3, 6/1(3) which leaves only one blot and cuts down on the potential damage never crossed my mind. Had I seen the play I'm sure I would have made it, but I never saw it.
3) See alternatives. It is very easy to focus on one thing and when the dice allow you to do that thing quickly make the move without looking closely to see if there is something even better. A good drill is to always try to find the second best move after you have found what you think is the best move. Even when the best move is obvious, this approach may open your eyes to other concepts in the position.
If Blue is playing quickly, he may see that the 4-2 roll makes his four point quite conveniently. After all, isn't that the way a 4-2 is supposed to be played? It is quite easy for Blue to make the four point and scoop up his dice without any further thought.
Suppose Blue went through the drill of finding the second best move even though he thought that making the four point was the best move. The natural play to look at is 22/16, getting the back checker out of danger and covering the outfield. In fact, the more Blue looks at this possibility the more he may become convinced that it isn't the second best move but the best move for the position. I believe that 22/16 is better than making the four point, but that is not what is important. What is important is that Blue considers the play as a candidate before making his move.
4) Have themes in mind. We have all watched experts play money games. They bang out their moves quickly, almost without thought it seems. How can they do this and consistently find the best or almost the best move? The key is that they are planning ahead, and they have a pretty good idea of what their priorities are in the position and what they will be doing with various dice numbers. As we have seen this can lead to trouble when it causes one to fail to see a move. Usually, however, concentrating on the right themes will have you looking at the right candidates. In the previous position, for example, any expert would know that his number one priority is to get that back checker out of trouble, not make points behind White's anchor. He would be mentally grabbing that checker even before the dice hit the table, and when he saw 4-2 his instinctive play would be 22/16 rather than 8/4, 6/4 because he knows that is where the priorities lie.
Blue has his choice of five points to make. It is clear that making the 20 point is correct, since Blue's back men would otherwise be in serious danger of being hemmed in. The expert would know this immediately, since his main concern would be doing something with those back checkers. He can see that his offense is fine as is, but if he doesn't do something good with the back men soon he will be in trouble. He is mentally reaching for those back checkers, planning on moving them someplace almost whatever is rolled. When the 4-3 appears, those checkers go instantly to the 20 point. This is not a play which is likely to be missed by any decent player, but it will be found quicker by the player who is concentrating on the highest priority.
5) Avoid plays which don't feel right. Sure sometimes the dice spit at us and we are forced to make ugly looking plays. Usually, however, there is some way to salvage things without tearing our position to shreds if we spend the time to search for it. If we make a play and it just doesn't feel right, there is often a good reason for it. Our instincts serve us pretty well if we are willing to listen to them. Take the play back and take another look. There may be something which you have missed, and subconsciously you know something is wrong.
I have seen many a player grab the checker on the eight point and play 8/2 in this sort of position. Yuck! One should instinctively know that this is unlikely to be the best play. That third checker on the two point is really weak. It can only be put in play with an ace, and then it goes to the ace point. This structure should be avoided if at all possible. Our instincts rebel against this position, so we should be looking for another play. A little effort reveals that the shifting play of 8/3, 2/1 is much more comfortable. Instead of no followup at all, White leaves himself with aces, fives, and sixes to make a fourth inner board point. This sort of shifting play is very common and easy to miss if you aren't willing to examine all the possibilities.
I have given just a few examples of the many kinds of positions where a player may totally overlook the best move. It happens to everybody. If you can force yourself to see and examine all the candidate plays, your checker play will take a big improvement.