Match Play

Forum Archive : Match Play

Doubling when facing a gammon loss

From:   Kit Woolsey
Date:   31 January 1999
Subject:   Re: Double When Facing Gammon

> I was in a 7 pt match trailing 3 to 5.  It looked to me like there was
> no way to run around and avoid a gammon, so I doubled.  My reasoning was
> that if I hit and won, I could win more points.  But if I didn't hit, I
> lost nothing extra by doubling.  Snowie disagrees with my double.  And
> maybe I should have looked at the possibility of hitting and avoiding a
> gammon instead of hitting and winning.  What do you think of doubling in
> the below position?
>            X on roll, cube action?
>            +24-23-22-21-20-19-------18-17-16-15-14-13-+
>            | X  O  O  O       |   |              X  X |
>            | X  O  O  O       |   |                 X |
>            |    O  O          |   |                 X | S
>            |    O  O          |   |                   | n
>            |       O          |   |                   | o
>            |                  |BAR|                   | w
>            |                  |   |                   | i
>            |                  |   |                   | e
>            |                X |   |                   |
>            |             X  X |   |     X             |
>            |          X  X  X |   |     X        X    |
>            +-1--2--3--4--5--6--------7--8--9-10-11-12-+

Your error is a very common one; I have seen experts make it several
times.  Clearly there is a small downside to doubling.  You might hit a
late shot when your opponent has borne almost all of his men off.  If
this happens you can save the gammon by building a prime and walking it
home, but you are still an underdog to win the game.  If this happens you
will be behind 4 away, 0 away -- no bargain, but it is better than losing
the match outright.

Is there an upside to doubling?  Your thinking that most of your losses
will be gammons is quite correct, so it would appear that there is more
to gain than to lose by doubling.  In fact, if your only options were to
double now or never double, then doubling now would probably be the
percentage move.

However, this is not your last chance to double.  If you wait, you will
have that option every time it is your turn to roll.  So, let's suppose you
wait, roll something, and your opponent rolls 4-3 and has to leave you a
shot.  Now let's suppose you double.  Will he take?  Of course he will.

Therefore, in your most favorable scenario for the next exchange (i.e.
you roll, he rolls), he will still have a take.  Consequently there is no
upside for doubling now.  To put it another way, it is impossible for you
to lose your market on the next exchange, since your opponent will always
have a take next turn no matter what happens.  Therefore doubling now is

If you get the shot next turn, it might be correct to double.  If your
opponent would have a pass after you hit the shot, then doubling would
probably be correct.  However if your opponent would still have a take
after you hit the shot, then doubling would be wrong for the same reason
-- you couldn't lose your market.

This is a very difficult concept to understand, and players often make
desparation doubles of this sort when uncalled for.  The main principle
is very simple: If it is impossible for you to lose your market on the
next exchange, then it is never correct to double.

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]

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