Match Equities

Forum Archive : Match Equities

 
ME Table: Snowie

From:   Harald Retter
Address:   harald.retter@okay.net
Date:   20 August 1998
Subject:   Snowie match equity chart
Forum:   rec.games.backgammon
Google:   6rhjv8$lfs$1@trader.ipf.de

Snowie uses its own match equity table, based on a gammon
rate of 26%. I couldn't find those equities summarized in
a diagram, so I spent some minutes to create one. As I am
not willed to memorize more than that, I did it up to -9.
Here is the result:

                  Your opponent needs
  You
  need|  1*   1    2    3    4    5    6    7    8    9
  ----+--------------------------------------------------
   1* | 50.0  --  51.5 68.5 69.5 81.3 81.9 88.8 89.1 93.3
   1  |  --  50.0 68.5 75.1 82.0 84.3 89.1 90.8 93.6 95.0
   2  | 48.5 31.5 50.0 60.4 68.5 75.3 81.0 85.1 88.5 90.9
   3  | 31.5 24.9 39.6 50.0 57.8 65.3 71.7 76.8 81.2 84.6
   4  | 30.5 18.0 31.5 42.2 50.0 57.9 64.6 70.3 75.2 79.4
   5  | 18.7 15.7 24.7 34.7 42.1 50.0 56.8 62.8 68.1 72.9
   6  | 18.1 10.9 19.0 28.3 35.4 43.2 50.0 56.3 61.9 67.1
   7  | 11.2 09.2 14.9 23.2 29.7 37.2 43.7 50.0 55.6 61.0
   8  | 10.9 06.4 11.5 18.8 24.8 31.9 38.1 44.4 50.0 55.5
   9  | 06.7 05.0 09.1 15.4 20.6 27.1 32.9 39.0 44.5 50.0

 *  = Post Crawford
-- = Retter-Paradox ;-)

While typing all those numbers, I was quite surprised how
similar they seemed to be to the Woolsey-table, I used to
work with (and actually still do). If my memory is right,
Kits tables where computed assuming a gammon rate of 20%.
Quite a difference, but the tables do not seem to reflect
on it much. So I created a second diagramm to display the
differences between the two versions. I took the numbers,
which are printed in "Cubes and Gammons..." by Ortega and
Kleinman and subtracted them from Snowie-values:

                             YON

   YN |  1*   1    2    3    4    5    6    7    8    9
  ----+--------------------------------------------------
    1*|  #    --   #    #    #    #    #    #    #    #
    1 |  --   0   -1.5 +0.1 -1.1 -0.9 -1.1 -0.5 -0.6 -0.1
    2 |  #   +1.5  0   +0.6 +0.7 +0.5 +0.2 +0.3 +0.5 +0.1
    3 |  #   -0.1 -0.6  0   +1.5 -0.5 +0.2 +0.4 +0.7 +0.2
    4 |  #   +1.1 -0.7 -1.5  0   -0.1 +0.2  0   -0.2  0
    5 |  #   +0.9 -0.5 +0.5 +0.1  0   -0.5 -0.5 -0.3 -0.4
    6 |  #   +1.1 -0.2 -0.2 -0.2 +0.5  0   +0.1 -0.4 -0.2
    7 |  #   +0.5 -0.3 -0.4  0   +0.5 -0.1  0   -0.6 -0.3
    8 |  #   +0.6 -0.5 -0.7 +0.2 +0.3 +0.4 +0.6  0   +0.2
    9 |  #   +0.1 -0.1 -0.2  0   +0.4 +0.2 +0.3 -0.2  0

# = only Snowie-data available

Oh, how nice, only four matchscores (-1-2/-1-4/-1-6/-3-4)
differ more than 1%point, the largest is 1.5%points. Once
these figures should get "accepted", there is not as much
to relearn as I feared. Most discrepancies appear at -1-T
(T = points to go for Trailer). As expected the increased
gammon rate favours the Trailer at these scores, with him
only having usage of those extra-points.

I am confused by the result for -4-3. A doubled gammon at
this score should be a big shot for the trailer,  winning
the match exactly outright.  His matchequity should raise
assuming a larger gammon rate. Food for thought,  who has
an idea?

Regards, Harald Retter
 
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Match Equities

Constructing a match equity table  (Walter Trice, Apr 2000) 
Does it matter which match equity table you use?  (Klaus Evers+, Nov 2005)  [GammOnLine forum]
Does it matter which match equity table you use?  (Achim Mueller+, Dec 2003) 
Does it matter which match equity table you use?  (Chuck Bower+, Sept 2001)  [GammOnLine forum] [Long message]
ME Table: Big Brother  (Peter Fankhauser, July 1996) 
ME Table: Dunstan  (Ian Dunstan+, Aug 2004)  [GammOnLine forum]
ME Table: Escoffery  (David Escoffery, Nov 1991) 
ME Table: Friedman  (Elliott C Winslow, Oct 1991) 
ME Table: Kazaross  (Neil Kazaross, Dec 2003)  [GammOnLine forum]
ME Table: Kazaross-XG2  (neilkaz, Aug 2011) 
ME Table: Rockwell-Kazaross  (Chuck Bower+, June 2010) 
ME Table: Snowie  (Chase, Apr 2002) 
ME Table: Snowie  (Harald Retter, Aug 1998) 
ME Table: Woolsey  (Raccoon, Apr 2006) 
ME Table: Woolsey  (Kit Woolsey, May 1994) 
ME Table: Woolsey  (William R. Tallmadge, Jan 1994) 
ME Table: Zadeh  (Jørn Thyssen, Mar 2004)  [GammOnLine forum]
ME Table: Zorba  (Robert-Jan Veldhuizen+, Dec 2003) 
ME at 1-away/2-away (crawford)  (Fabrice Liardet+, Nov 2007)  [GammOnLine forum]
ME at 1-away/2-away (crawford)  (Ian Shaw+, Apr 2003)  [GammOnLine forum]
Match equities--an alternate view  (Durf Freund, Oct 1994) 
Neil's new numbers  (neilkaz, Aug 2011) 
Neil's numbers  (Kit Woolsey+, Oct 1994) 
On calculating match equity tables  (Neil Kazaross, July 2004)  [GammOnLine forum]
Turner formula  (Gregg Cattanach, Feb 2003) 
Turner formula  (Stephen Turner, June 1994) 
Using a match equity table  (Michael J. Zehr, June 1992) 
Value of free drop  (Neil Kazaross, Oct 2002)  [GammOnLine forum]
Which match equity table is best?  (Martin Krainer+, Oct 2003) 
Which match equity table is best?  (Ian Shaw+, Dec 2001) 
Why use a match equity table?  (Kit Woolsey, Feb 1999) 
Worth memorizing?  (Alef Rosenbaum+, Feb 2003) 

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