Match Equities

Forum Archive : Match Equities

Value of free drop

From:   Neil Kazaross
Date:   28 October 2002
Subject:   Free drop equity using GNU and SW
Forum:   GammOnLine

In preparation for a more modern equity table that I'll be publishing
in a while that will take into account the higher gammon percentages
obtained by bots and likely some bot rollouts as well, I decided to
using both Snowie 4 and GNU to see what they think the equity is at
-2-1 Post Crawford.

I used Snowie 4 on 3 ply precise and took the equity from each of the
best plays for each side for each of the 15 opening rolls. The cubeful
look ahead actually sees the situations it thinks are slightly too good
to cube and also see situations that it thinks are passes after poor
opening throws by the leader. GNU's cubeful look ahead also sees the
same things. Thus, the cubeful look ahead simply can be set to display
the respective bot's opinion of match equity after each of 30 plays.
I did the GNU analysis on 3 ply (which took a while since it is like
Snowie 4 ply)

Anyhow..according to Snowie 4, the trailer's match equity when the
leader has 1 free drop is 48.74 %

According to GNU this match equity is 48.72 %.

If one averages the two very close numbers one can safely use 48.73% as
the match equity at -2-1 Post Crawford.

I realize that rollouts could change this a bit, but I am not considering
doing them at the moment.

> So you mean that if I am behind (-2,-1, post crawford), and I win the
> opening roll, after my move, and my opponents move, sometimes my opponent
> has a drop, but I play on, hoping to win the match with a gammon, rather
> than doubling him out (and letting him use his free drop), and then
> playing the next game for the match?

I didn't really believe this either, but then the German master and author
Harald Johanni did some interactive rollout using JF and his data seemed
pretty conclusive. You basically need a very good opening roll like 31 and
your opponent needs to to throw a poor shot in return. For example after 31
followed by a poor shot like 63 it should be worth the risk of regaining
one's market (becoming an underdog after the worst sequences) to hope to
throw a joker and get real gammon chances. GNU and Snowie agree that some
positions like that are too good at this score.

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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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