Cube Handling

Forum Archive : Cube Handling

PRAT--Position, Race, and Threats

From:   Alan Webb
Date:   6 February 2001
Subject:   Re: How to analyze a cube action?
Google:   95oj2m$m3v$

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
           | 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 |
           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
           |          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 |
           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
           | 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 |
           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


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 :-)


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Cube Handling

Against a weaker opponent  (Kit Woolsey, July 1994) 
Closed board cube decisions  (Dan Pelton+, Jan 2009) 
Cube concepts  (Peter Bell, Aug 1995)  [Long message]
Early game blitzes  (kruidenbuiltje, Jan 2011) 
Early-late ratio  (Tom Keith, Sept 2003) 
Endgame close out: Michael's 432 rule  (Michael Bo Hansen+, Feb 1998)  [Recommended reading]
Endgame close out: Spleischft formula  (Simon Larsen, Sept 1999) 
Endgame closeout: win percentages  (David Rubin+, Oct 2010) 
Evaluating the position  (Daniel Murphy, Feb 2001) 
Evaluating the position  (Daniel Murphy, Mar 2000) 
How does rake affect cube actions?  (Paul Epstein+, Sept 2005) 
How to use the doubling cube  (Michael J. Zehr, Nov 1993) 
Liveliness of the cube  (Kit Woolsey, Apr 1997) 
PRAT--Position, Race, and Threats  (Alan Webb, Feb 2001) 
Playing your opponent  (Morris Pearl+, Jan 2002)  [GammOnLine forum]
References  (Chuck Bower, Nov 1997) 
Robertie's rule  (Chuck Bower, Sept 2006)  [GammOnLine forum]
Rough guidelines  (Michael J. Zehr, Dec 1993) 
Tells  (Tad Bright+, Nov 2003)  [GammOnLine forum]
The take/pass decision  (Otis+, Aug 2007) 
Too good to double  (Michael J. Zehr, May 1997) 
Too good to double--Janowski's formula  (Chuck Bower, Jan 1997) 
Value of an ace-point game  (Raccoon+, June 2006)  [GammOnLine forum]
Value of an ace-point game  (Øystein Johansen, Aug 2000) 
Volatility  (Chuck Bower, Oct 1998)  [Long message]
Volatility  (Kit Woolsey, Sept 1996) 
When to accept a double  (Daniel Murphy+, Feb 2001) 
When to beaver  (Walter Trice, Aug 1999) 
When to double  (Kit Woolsey, Nov 1994) 
With the Jacoby rule  (KL Gerber+, Nov 2002) 
With the Jacoby rule  (Gary Wong, Dec 1997) 
Woolsey's law  (PersianLord+, Mar 2008) 
Woolsey's law  (Kit Woolsey, Sept 1996) 
Words of wisdom  (Chris C., Dec 2003) 

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