Match Play

Forum Archive : Match Play

 
When to free drop

From:   Gregg Cattanach
Address:   gcattanach@prodigy.net
Date:   31 December 2004
Subject:   Win the opening roll, take the free drop?
Forum:   GammOnLine

Recently, I had a couple matches analyzed where Snowie indicated that
even though I won the opening roll I was supposed to take the free drop
(at 1-away, 2-away post-Crawford). I decided to roll all these out and
see if there really were some plays where this would be right.

I assumed that if I made a point on the first roll (other than 64) then
I'm a favorite and should take, these I didn't roll out. The rest I did
with Snowie. Then I did them all with Gnu 0-ply. On most of the plays
that the two bots disagreed I did another rollout with Gnu 2-ply.

The Gnu rollouts are probably a bit better as they are moving the
checkers as the DMP game that it really is.

Conclusions:

You should always split with your opening roll, including all 6x rolls.
Exception: slot with 21. 24/21 13/9 looks to be the best split with 43.

It looks like with 52 and 41 you should drop, the rest you should take.

Here's the chart: Percentages are the single games won by the 1-away
player that won the opening roll. ** is where Snowie and Gnu disagreed.

                     Rollout         Rollout           Rollout
Play            Snowie 2-ply     GnuBG 0-ply       GnuBG 2-ply
--------------  -----------      -----------       -----------
21 13/11 6/5    Take  50.5%      Take  51.0%
21 24/23 13/11  Take  50.3%      Pass  49.5%  **
31 8/5 6/5      Take  55.4% NR
32 24/21 13/11  Take  50.1%      Take  50.5%
32 13/8         Pass  48.2%      Pass  48.8%
32 13/11 13/10  Pass  49.5%      Pass  49.7%
41 24/23 13/9   Pass  49.6%      Pass  49.7%
41 13/9 6/5     Pass  49.7%      Pass  49.7%
42 8/4 6/4      Take  53.6% NR
43 24/21 13/9   Pass  49.9%      Take  50.2%  **   Take  50.2%
43 24/20 13/10  Pass  49.7%      Pass  49.7%
43 13/10 13/9   Pass  49.6%      Take  50.3%  **   Pass  49.7%
51 24/23 13/8   Take  50.2%      Take  50.0%
51 13/8 6/5     Pass  49.3%      Pass  49.1%
52 24/22 13/8   Take  50.6%      Pass  49.7%  **   Pass  49.9%
52 13/11 13/8   Pass  49.3%      Pass  49.9%
53 8/3 6/3      Take  51.6% NR
54 24/20 13/8   Take  50.6%      Take  50.5%
54 13/9 13/8    Pass  49.6%      Pass  49.8%
61 13/7 8/7     Take  53.4% NR
62 24/18 13/11  Take  50.8%      Take  51.0%
62 24/16        Take  50.3%      Take  51.0%
62 13/5         Pass  49.2%      Pass  49.4%
63 24/18 13/10  Take  50.7%      Take  51.2%
63 24/15        Take  50.6%      Take  50.0%
64 24/18 13/8   Take  50.6%      Take  50.4%
64 24/14        Pass  49.9%      Take  50.4% **    Take  50.4%
64 8/2 6/2      Pass  49.8%      Pass  49.2%
65 24/13        Take  52.5% NR

                864 games,       1296 games full, 1296 games full,
                2-ply, precise,  0-ply checkers,  2-ply checkers,
                full             2-ply cube       2-ply cube
 
Did you find the information in this article useful?          

Do you have any comments you'd like to add?     

 

Match Play

1-away/1-away: advice from Bernhard Kaiser  (Darse Billings, July 1995)  [Long message] [Recommended reading]
1-away/1-away: advice from Stick  (Stick+, Mar 2007)  [GammOnLine forum]
1-away/1-away: and similar scores  (Lou Poppler, Aug 1995) 
2-away/3-away: playing for gammon  (Tom Keith, Feb 1996) 
2-away/4-away: Neil's rule of 80  (Neil Kazaross, June 2004)  [GammOnLine forum]
2-away/4-away: cube strategy  (Tom Keith, Dec 1996) 
2-away/4-away: practical issues  (Mark Damish, Jan 1996) 
2-away/4-away: trailer's initial double  (Kit Woolsey, Jan 1996) 
3-away/4-away: opponent's recube  (William C. Bitting+, Feb 1997)  [Long message]
3-away/4-away: racing cube  (Bill Calton+, Nov 2012) 
3-away/4-away: tricky cube decision  (Kit Woolsey+, July 1994) 
3-away/4-away: what's the correct equity?  (Tom Keith, Sept 1997) 
4-away/4-away: take/drop point  (Gary Wong, Oct 1997) 
5-away/11-away: redouble to 8  (Gavin Anderson, Oct 1998) 
7-away/11-away: volatile recube decision  (Kit Woolsey, May 1997) 
Both too good and not good enough to double  (Paul Epstein+, Sept 2007) 
Comparing 2-away/3-away and 2-away/4-away  (Douglas Zare, Mar 2002) 
Crawford rule  (Chuck Bower, May 1998) 
Crawford rule  (Kit Woolsey, Mar 1997) 
Crawford rule--Why just one game?  (Walter Trice, Jan 2000) 
Crawford rule--history  (Michael Strato, Jan 2001) 
Delayed mandatory double  (tem_sat+, Oct 2010) 
Delayed mandatory double  (Donald Kahn+, Dec 1997)  [Recommended reading]
Doubling when facing a gammon loss  (Kit Woolsey, Jan 1999) 
Doubling when opponent is 2-away  (David Montgomery, Dec 1997) 
Doubling when you're an underdog  (Stein Kulseth, Dec 1997) 
Doubling window with gammons  (Jason Lee+, Jan 2009) 
Free drop  (Ian Shaw, May 1999) 
Free drop  (Willis Elias+, Oct 1994) 
Gammonless takepoint formula  (Adam Stocks, June 2002) 
Going for gammon when opp has free drop  (Kit Woolsey, Jan 1998) 
Going for gammon when opp has free drop  (Kit Woolsey, Apr 1995) 
Holland rule  (Neil Kazaross, Apr 2010) 
Holland rule  (Kit Woolsey, Dec 1994) 
Leading 2-away with good gammon chances  (Douglas Zare, Feb 2004)  [GammOnLine forum]
Match play 101  (Max Urban+, Oct 2009) 
Matches to a set number of games  (Tom Keith+, Oct 1998) 
Playing when opponent has free drop  (Gilles Baudrillard+, Dec 1996) 
Post-crawford doubling  (Scott Steiner+, Feb 2004) 
Post-crawford doubling  (Maik Stiebler+, Dec 2002) 
Post-crawford doubling  (Gus+, Sept 2002) 
Post-crawford mistakes  (Rob Adams, Sept 2007)  [GammOnLine forum]
Post-crawford/2-away: too good to double  (Robert-Jan Veldhuizen, July 2004) 
Slotting when opponent has free drop  (onur alan+, Apr 2013) 
Take points  (fiore+, Feb 2005)  [GammOnLine forum]
Tips to improve cube handling  (Lucky Jim+, Jan 2010) 
When to free drop  (Dan Pelton+, Oct 2006) 
When to free drop  (Tom Keith+, July 2005)  [GammOnLine forum]
When to free drop  (Gregg Cattanach, Dec 2004)  [GammOnLine forum]
When to free drop  (Kit Woolsey, Feb 1998) 
When to free drop  (Chuck Bower, Jan 1998) 
Which format most favors the favorite?  (Daniel Murphy+, Jan 2006)  [GammOnLine forum]

[GammOnLine forum]  From GammOnLine       [Long message]  Long message       [Recommended reading]  Recommended reading       [Recent addition]  Recent addition
 

  Book Suggestions
Books
Cheating
Chouettes
Computer Dice
Cube Handling
Cube Handling in Races
Equipment
Etiquette
Extreme Gammon
Fun and frustration
GNU Backgammon
History
Jellyfish
Learning
Luck versus Skill
Magazines & E-zines
Match Archives
Match Equities
Match Play
Match Play at 2-away/2-away
Miscellaneous
Opening Rolls
Pip Counting
Play Sites
Probability and Statistics
Programming
Propositions
Puzzles
Ratings
Rollouts
Rules
Rulings
Snowie
Software
Source Code
Strategy--Backgames
Strategy--Bearing Off
Strategy--Checker play
Terminology
Theory
Tournaments
Uncategorized
Variations

 

Return to:  Backgammon Galore : Forum Archive Main Page