Mark Driver wrote:
> I found Paul Lamford's (100 Backgammon Puzzles) concise cube advice to
> be effective, simple and easy to remember.
> Paul uses the acronym PRAT as a guide to doubling and accepting:
>
> PRAT stands for - Postion, Race And Threats
>
> Paul recomends to double when you have an advantage in two of these three
> areas. If you have a clear advantage in all 3, then your opponents should
> pass.
You beat me to it Mark :-)
I just want to add a little more about the "PRAT" method. First of all it
is easy to remember as you just ask yourself not to be a "PRAT" on doubling
decisions :-) "Prat" btw in english, english is a derogatory term meaning
"Idiot" Not sure if you can say it across the pond though :-)
Since I read Paul Lamford's book, about 6 months ago now, I have used this
method pretty much extensivly. I tested it in fact recently against the
doubling positions in Roberties "501 essential bg positions" by not relying
on experience but simply solely using the method described. I found that
the results were impressive and I made a marked improvement from when I
first tried them using just experience, especially in contact positions.
I have tweaked the general principal slightly myself in that I attach
weightings to each of the 3 main areas. Meaning for example, if all things
being equal, I will weigh in the pip count higher than the threat and
position areas. I also take good account of the score in match play and
gammon potential both ways.
The method itself is not that much good to a real beginner however as you
still need to know if your position is in fact better and still need to
know if you have any threats and what they are. For those with a reasonable
understanding of the game, say 1550+ I believe it can help a long way. It
isn't perfect as there are some positions where other factors override the
result of the method, particular prime vs prime positions, but it has
helped my game along nicely and I'm making far fewer doubling errors than I
used to.
Just to illustrate things let's see the guidelines in action...
O on roll, cube action
+-1--2--3--4--5--6--------7--8--9-10-11-12-+
| X O O O | | O O X |
| X O O O | | O X |
| O | | X | S
| O | | X | n
| | | | o
| |BAR| | w
| | | | i
| | | | e
| X | | |
| X O X | | X X O |
| X O X | | X X O |
+24-23-22-21-20-19-------18-17-16-15-14-13-+
Pipcount X: 150 O: 132 X-O: 0-0/3 (1)
CubeValue: 1
X O
---------------------------
Position| - * Better board, high anchor.
|
Race | - * O is 18 pips ahead and on roll
|
and |
|
Threats | - * Positioned well to make bar or 4 point.
From the above we gather that O has the better Position, is ahead in the
Race and Threatens to make the bar or 4 point.
So if we use the criteria that 3 areas in your favour should be double /
pass, then the correct cube action must be double / pass. Snowie agrees...
1. Double, pass 1,000
2. No double 0,920 (-0,080)
3. Double, take 1,210 (+0,210)
How about this one...
O on roll, cube action
+-1--2--3--4--5--6--------7--8--9-10-11-12-+
| O X O | | O O X |
| O O | | O O X |
| O | | O X | S
| | | X | n
| | | X | o
| |BAR| | w
| X | | | i
| X | | O | e
| X | | X O |
| X | | X O |
| O X X | | X O |
+24-23-22-21-20-19-------18-17-16-15-14-13-+
Pipcount X: 143 O: 148 X-O: 1-1/3 (3)
CubeValue: 1
X O
----------------------
Position| - * Better board, 11 point
|
Race | * - O trails by 5 pips.
|
and |
|
Threats | - * Pointing on the 5 pnt, hitting on 21, 2 checkers up
So O has 2 out of the 3 areas which according to the general rule is a
double / take.
Snowie sayssss...
1. Double, take 0,732
2. No double 0,666 (-0,067)
3. Double, pass 1,000 (+0,268)
Proper cube action: Double, take
Last but not least...
O on roll, cube action
+-1--2--3--4--5--6--------7--8--9-10-11-12-+
| O O O O O | | O X |
| O O O O | | |
| O | | | S
| | | | n
| | X | | o
| |BAR| | w
| | | | i
| | | | e
| X | | O |
| X X X X | | X X O |
| X O X X X | | X X O |
+24-23-22-21-20-19-------18-17-16-15-14-13-+
Pipcount X: 108 O: 113 X-O: 0-0/5 (1)
CubeValue: 1
X O
----------------------
Position| - * O clearly has the better board and remains flexible
|
Race | * - O trails by 5 pips.
|
and |
|
Threats | - * Numerous. Covering, hitting, escaping etc.
So what we have here is 2 out of 3 of the areas so according to the
guideline this is a double/take right?
1. Double, pass 1,000
2. No double 0,731 (-0,269)
3. Double, take 1,151 (+0,151)
Proper cube action: Double, pass
Wrong!
This is why you should only use it as a general guideline. Here the
position and threats are so great that they override the small pip deficit.
Gammon is another factor and X is so inflexible with buried checkers and
...etc etc. If you are going to use the method then look out for positions
where one area clearly overrides the others.
Also beware that not all "good in all 3 areas" are double / passes. They
may not even be doubles of course as you may well be too good to double.
Anyway, it works for me :-)
regards
Alan
Webby's Backgammon Site
quizzes, downloads, tips, annotated matches, links...
www.isg-vsg.de/backgammon/BGHome.
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