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Red is on the bar and on roll, trailing 0-2 to 5. Cube action?

 

 

 

FencepostCorner04.png

 

A lot of players double this and their thinking goes as follows. “Well, if I lose this game I am certain to be gammoned and that will mean that I trail 0-4 Crawford, in other words practically dead, so I may as well double now”. The flaws in that reasoning are firstly that he isn’t certain to be gammoned, because he often hits now or later and loses a plain game and secondly that 0-4 Crawford is anything but dead! You still have 15% match winning chances from there.

 

A rough breakdown of the outcome of this game is that White wins 55% of the games from here, divided into 17 backgammons, 21 gammons and 17 plain wins. Doubling now renders the backgammons redundant, which is handy and reduces the value of the gammons, because White will only be able to use one of the two extra points that a doubled gammon will win. The downside is that plain wins now get White to Crawford and that is very damaging. Do you need to be able to guesstimate these percentages at the table in order to decide upon your strategy? No you don’t. Just ask yourself some simple questions.

 

(1) If I double, is there any doubt as to whether this is a take? If the take is in doubt, it must be a double but here it isn’t. A take is as clear as day. It might still be a double of course, so go on to step 2.

 

(2) Is there any chance of getting a wrong pass? If there is, a wrong double might just be right or a weak double would be stronger, but here there is absolutely no chance of a pass. Nobody passes this, ever.

 

(3) There must be some market losers for any double to be correct. Is there a sequence here where if I roll my best and he rolls his worst I can cash? Here, even if Red rolls 6-6 and White fans, White will still have a take and in fact it still won’t even be a correct double!

 

(4) From here, how hard is this to play for either of us? You need to ask this, because in many situations human players are not capable of achieving the theoretical equity of a position! In this position, the bots tell us that Red blunders by doubling, giving away about one-third of a point, or if you prefer, reducing his match winning chances from 28% to 25%. That assumes near perfect play on both sides, but here you won’t see that. White will play almost perfectly from here because her play will be trivially easy whether hit or not, whereas Red will face many tough plays if he manages to hit, whether now or later. Even a strong player (and Red is 1800 on fibs) is likely to make a number of errors as he tries to arrange his outfield checkers in an optimal pattern to contain a straggler. This means that if his double was marginally correct technically speaking, he should probably still wait until he is a little stronger.

 

The key skill that you need in backgammon, is to arrange your thoughts so that you can use the knowledge that you have. A checklist of questions when considering cube action is a good way to organize your thoughts. You may be able to devise a better system for yourself but you do need a system. It’s no use knowing the answer if you don’t know the question! Think about this. It is the reason that many knowledgeable gammoners don’t play as well as they could.

 

Until next time, Enjoy the game!

 

Comments: 3 *

1) Re: Improvers Corner Number Four.
Comment by padski on January 21, 2007, 12:29:01 PM

where is the board ?
2) Re: Improvers Corner Number Four.
Comment by diane on January 21, 2007, 12:50:28 PM

Ok - without a board I am struggling a bit to visualise this, so I am struggling with some statements.
Firstly - 'Red wins 55% of the games from here, divided into 17 backgammons, 21 gammons and 17 plain wins. Doubling now renders the backgammons redundant'.  If Red trails 0-2, the backgammons are great for him - surely, if he has cubed.
If red wins 55% of games, then why no cube?  If he waits until that number goes up to, say 90%, then it wont be a  take - and that market is lost, whereas with 55%, it would seem to me there is a cube.

Having said that - I am not sure I would cube this
3) Re: Improvers Corner Number Four.
Comment by webrunner on January 21, 2007, 10:39:26 PM

The board is visible now.
I wouldn't cube this BTW (but who am i?)
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