Match Play

Forum Archive : Match Play

Post-crawford doubling

From:   Maik Stiebler
Date:   2 December 2002
Subject:   Re: 2 Post-Crawford games: why are these passes?

The difference between post-Crawford odd-away and post-Crawford
even-away cannot be stressed enough. At odd-away, the leader actually
has a "free TAKE"!
Would you ever drop if you were doubled at 6-6 in a 7-point-match?
Well, dropping while leading 6-4 is usually nearly as bad. If you
cannot be gammoned, you can take with game winning chances as small as
It's quite common for the trailer to delay doubling until he thinks
his hopefully less knowledgeable opponent will erroneously pass. The
leader can avoid this trap by deciding (and maybe even announcing)
before the game that he will take trailer's double no matter when it
comes. Doing so would not reduce leader's equity, though it is not
optimal in the case that trailer errs by losing his market.

Ian Dunstan  writes:

This begs the question: Can you be "too good to double" in this or
similar odd-away situations? Winning 2 points does not help the
trailer much in terms of MWC.  But winning an undoubled backgammon
certainly does.  Therefore, if Trailer looses his market, as in the
case above, should he play on hoping for a backgammon?  I think that
as long as you don't risk an exchange where you let the Leader back
into "take" territory you could reasonably play on the backgammon.

Douglas Zare  writes:

Yes, definitely you can be too good to double. This is true even without
the possibility of backgammons. In some positions, you will have a huge
gammon threat even after a setback, so your opponent will be unable to
take after any exchange, so you should play on for the gammon. With enough
backgammon potential, it may be worth it to risk regaining your market.

If you close 3 checkers out in ordinary circumstances (money play with
your opponent holding the cube) and ideally placed spares, you should win
more than 8% backgammons. It depends on the state of your opponent's
offense, thus how much you have to avoid getting hit. With 4 checkers
closed out you should win at least 25% backgammons. Most players,
including current bots, do not play aggressively enough for the
backgammon. They view it as a freak occurence, even though when you close
3 out winning a backgammon should be more common than losing. I've won 3
valuable backgammons in 14 live tournaments, including from trailing
2-away 5-away with the cube on 2 in a final, so I don't discount their

By the time you close out 3 checkers, you are certainly too good to double
at post-Crawford 3-away. The question is how you could get to such a
situation. You can't with perfect play by both sides, but I think it might
be reasonable not to double if you only have a couple of market losing
exchanges in 1296 if you are sure that your opponent will take now. Then if
you get one of the market losers, you might be too good to double if the
position is not volatile, e.g., you have manufactured a 6-prime that will
still be there next turn. (Be careful that a 6-prime is far from gin,
though, so if the gammon chances go down your opponent may have a take.)

At post-Crawford 5-away, backgammon wins are huge on a 2-cube. The
difference between winning a backgammon and winning a gammon is the same as
the difference between winning a gammon and losing! Although I think there
is more room to benefit from bad passes of delayed doubles, a real risk of
backgammons (count your opponent's blots) is a strong argument against
actually losing your market.

Douglas Zare
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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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