the dorbel daily

Thursday, 23 February 2012

Learning To Love The Cube

There are several ways to approach improving one’s checker play but for me, the most important feature is your attitude to the cube. How do you view it? I want to divide this into Doubling and Taking, because the two skills are actually quite different. I see doubling as being much more important. This is because we typically face many more doubling decisions than taking decisions, as obviously we only consider a take when we get cubed, but have to consider doubling several times in every game.

World Class players, without exception, are eager to turn the cube at the first reasonable opportunity. They actively look for chances to double very early, as early as the bots and much earlier than players below expert level. There attitude is, “I think that this might be a cube, it’s certainly very close, so even if it is a small mistake, I’ll turn it now.”

If you are not actively looking for these opportunities as soon as you think that you have an advantage in the game, you are certain to miss them. Bear in mind that they adopt this policy even when they are playing another player of their own standard, so they have worked out that this attitude is technically correct. For the rest of us playing opponents that are anything but World Class, it is even more likely to be the right policy. Why? Look at it like this.

Doubling on the first roll that you think that you may have a double has some hidden benefits. The first is that it allows your opponent the chance to make a mistake. Choosing not to double does not do this. “But”, I hear you say, “If I double very early then there is no chance that she will make a mistake and wrongly pass”. There is less chance certainly, but there will be some wrong passes and when they do come along, they will be huge blunders. One blunder that gives away 0.3 or 0.4 of a point (and these do happen) will pay for a lot of slightly early cubes. There is more. Once you have cubed, you can’t then make subsequent cube errors in that game, unless of course you get recubed later. There is more too. Part of the equity of the player taking the cube resides in her ability to use it efficiently later, but only very, very strong players do this. If your opponent isn’t an expert, the chances are that she will miss her chance to redouble you in later and/or cash when she is too good to double. By giving her the cube it’s true that you give her some theoretical equity, but that will only help her if she uses it well and the chances are that she won’t. By cubing early then, you not only kill your own chances to make a later cube error, but you open up the possibility that she will do so!

“If I wait until I am stronger, then there is much more chance that she will make a bad pass”. This is absolutely true, but there are two things to consider here. The first is that you risk losing your market. The second is that the possible mistake that she can make is much smaller. If for example you wait until your equity is say 0.95 of a point after a double and take, then it is true that her take/pass decision will be very difficult, but if she makes the wrong decision, it only costs her 0.05 of a point.

The second kind of doubling decision is, “Am I too good to double?” This is one of the nicest decisions that we face of course, difficult to get right but always meaning that we are in a very strong position. I have a very simple rule for this. I only play on for a gammon if I am 100% certain that I am too good and if I do, I make sure that I keep reviewing that decision on every roll. How does this work in practice? It means that I make some small errors when I am technically too good (i.e. worth more than a point a game on this roll). However there are two compensating factors that more than make up for these errors. The first is the possibility of wrong takes, which are always huge blunders. Not very likely? Show me the player who has never taken a cube that was actually too good. I have and Iam quite sure that I will do again. They come up a lot and it only takes one of these every now and then to pay for a lot of small errors when they correctly pass.

The second is that when they correctly pass, it puts a concrete point on to the scoresheet. It isn’t theoretical equity, it’s a real point and I don’t have to play to get it!

So, we need an aggressive attitude that actively wants to double and we need a way of approaching each roll that gives us the time to consider a cube. Now of course we get to the difficult part, which is trying to figure out our winning chances so that we can see if we should be doubling. I’ll digress for a moment though, to say that experts never think to themselves, “What if he takes and turns it round and I lose?” They only think, “Is it a double?” However, looking at the position from our opponent’s point of view can paradoxically lead us to the correct cube action. This is the legendary Woolsey Rule. Invented by the great theoretician and player Kit, it simply states, “Are you 100% sure that this is a take?” If not, it must be a double.” Even easier, you can simplify it further to the dorbel rule. “If I was him, would I want to be doubled here?” No? Ship it in!

Food for thought? I hope so. Let me know what you think of this and please, ask questions.

Tomorrow we'll look at taking and passing and actually look at some real positions.

Until then, enjoy the game and get that cube moving!


Epitaxi said...

"Even easier, you can simplify it further to the dorbel rule. “If I was him, would I want to be doubled here?” No? Ship it in!"

Easy, fun and probably a good rule for me as a novice to remember. Want to thank you for a great blog, the discussions and tips are great.

boop said...

great post Dorbel
something you said elsewhere sticks in my mind too - learning to refine an overly aggressive cubeing style is much easier, more intuitive, than strengthening a weak cubeing style. You can see the results of your cube, whereas a cube inaction just exists in a fog of statistical uncertainty - something like that :-)

markx said...

Great article about one of the most common BG problems!
"Part of the equity of the player taking the cube resides in her ability to use it efficiently later, but only very, very strong players do this."
An additional point on this aspect: Some players, who usually cube passably, might get overly timid when the cube goes to 4 or even higher.