This article originally appeared in the February 2000 issue of GammOnLine.|
Thank you to Kit Woolsey for his kind permission to reproduce it here.
The main advantage bots have over us mere mortals is their ability to
grasp the big picture. When it comes to technical issues such as races,
bearing in safely, or maneuvering to jar a second checker loose from a back
game, experts can outplay the bots. These positions require focus only
on a specific side of the board. What is happening on the other side of
the board doesn't make much difference.
For most positions, the whole board matters. Whether or not to take a certain risk on one side of the board is often a function of what the other side of the board looks like, not just the side of the board where the risk is being taken. The neural networks of the bots can synthesize all of this information and weigh it together properly to usually come to the correct conclusion. This is something which we have to learn to be able to do if we are going to improve our game.
Here is a simple early game example:
Blue has a choice of five points to make. In general, offense comes before defense. Blue's offensive position improves dramatically after playing 8/5, 6/5. With the White checkers hemmed in on the ace point, Blue has a good chance to win a priming battle. His own back men aren't in great danger, so it isn't urgent for him to make the advanced anchor.
However, a slight change in the position changes the priorities.
Now making the offensive five point doesn't gain as much. White has an advanced anchor, so Blue can't hem White in. It is more important for Blue to counter with an advanced anchor of his own. If he fails to do so, he risks finding himself on the wrong end of a priming battle. Even though 24/20, 23/20 leaves White the direct shot at the blot on the nine point, it is still the superior play. The change in White's defensive structure shifts Blue's priorities from offense to defense.
There is no need to risk the action play of B/18. Blue is in fine shape, and by playing B/24, 13/7 he can bring down some ammunition to make a new point. With White penned in on Blue's ace point, Blue figures to be in good shape in a priming battle. Playing B/18 just gives White a chance to batter Blue around and safely split his own back checkers.
Contrast this with:
This is another story. White has an advanced anchor, so playing B/24, 13/7 isn't particularly productive. Blue isn't going to be able to hem White in. If Blue doesn't fight on White's side of the board with B/18, White will bring the builders down and hem Blue in. This time it is imperative to play B/18. White may hit, but then Blue has a chance to hit back. Note how the change of what has happened on the other side of the board makes the split correct now when it wasn't correct before.
The situation on the other side of the board is often vital when considering pay me now or pay me later problems. Here is an example:
Contrast this with:
This is another story. White has a solid five-prime, so if he hits a shot he will be a favorite to contain the hit checker. This time Blue is better off playing the number in his inner board and hoping to roll doubles later to clear the midpoint. Getting hit now would be fatal.
The situation on the other side of the board can often affect blitz decisions. The weaker the opponent is, the more aggressive you can be with your attack.
The problem of whether to hit a second checker and prevent your opponent from anchoring or to make a new inner board point is a common dilemma when running a blitz. There are many factors invovled, but a crucial one is the state of your opponent's board. In this position White has no board at all, so even if Blue hits loose and White hits back Blue figures to have little difficulty escaping. The gain from putting a second checker on the bar and preventing White from anchoring is large. Blue has plenty of ammunition left to fight with. Blue should play 6/4*, 4/3*.
A slight difference on the other side of the board can change things.
Now White has made the five point. This changes things. If Blue hits two checkers and White hits back, suddenly White is back in the game. That made five point gives White a fighting chance in a blot-hitting contest, and sends him on his way toward containing any hit checkers. It isn't worth the risk. Blue should simply play 6/4*, 5/4 and hope that White doesn't anchor.
Timing considerations on the other side of the board can often affect your checker play. For example:
10/7, 9/7 is an awkward play. Piling four checkers on the bar point restricts Blue's flexibility. Now if he rolls fives and fours he will be forced to take these checkers deep, which will hurt him later in when bearing off against the ace-point anchor. The advantage of the play is that it kills Blue's sixes. If Blue rolls a six next turn he won't have to play it, which permits him to retain his prime longer. Since White is on the verge of crunching, holding that prime one extra roll could be quite significant. If White is forced to crunch his board, it won't be nearly as serious if and when White hits a shot later on. Blue should play 10/7, 9/7.
This time White is already crunched. There isn't much more damage that can be done to his board, so Blue doesn't gain by holding the prime an extra roll. Now Blue should play the more flexible 10/8, 9/6. The different structure on the other side of the table changes Blue's play.
The full board picture is often of vital importance for cube decisions. Consider the following well-known type of position:
A classic five-point holding game. Blue has a solid double. Despite the race deficit, White has a comfortable take. He has some small racing chances, along with the possibility of hitting a shot. These combined possibilities are sufficient to get him over the 25% mark. However, change the position to:
Same holding game, same pip count. The difference is that White has no board, and he will have some difficulty building up a board. This means that hitting a shot is no longer a virtual winner for White -- he will still have some work to do. This is sufficient to swing what was a solid take into a pass.
Cube decisions involving blitzes are the trickiest of all. There are a ton of factors involved, but the most underrated one is the strength of the blitzee's board.
Blue has a strong blitz potential. To make matters worse for White, he has no board. This means that if White starts to survive the blitz by hitting a shot Blue will be able to get right back in and White will still have to work to get an offense going. This fact combined with the obvious danger that Blue's blitz might succeed is sufficient to give White a clear pass.
The difference here is that White no longer has an outfield blot hanging. This means that even if Blue gets the blitz going, he won't have any other checkers to scoop up. This change is sufficient to no longer give Blue a double. Quite the change. From double-pass to double-take to no double with the same blitz threat, depending on what is happening on the other side of the board.
These are just a few of the many types of positions where what is happening on one side of the board affects the play on the other side of the board. Backgammon is a complex game where all the pieces interact with one another. It is necessary to get the big picture of this interaction in order to understand the position and find the right play.