Forum Archive :
Would it not be right to say that when making a decision to double, or
to play on for a gammon, that it makes a difference who your opponent
is? If I was playing in a tournament, and happened to be paired against
Kit. I think that I would be a little quicker to double with an
advantage. My feeling is that due to the talent of my opponent, I have a
lower chance of winning each game from the very beginning. Therefore, I
would count one point on the score sheet higher than the chance to play
on for a gammon. I would also be quicker to double with a small
advantage, figuring that if I played every game for two points, I have
more chance of being lucky and winning.
Douglas Zare writes:
It makes a huge difference who your opponent is, particularly in money
play. In chouettes I often see successful incorrect doubles that provoke
a bad pass, a bad take, or a bad beaver when doubling is an error and
I'm confident that the doubler knows it, and does not expect the
stronger players in the chouette to misjudge the position.
I think it is very common for an opponent's supposed weakness to be an
invalid excuse for bad play. Some people will make a blunder to provoke
a smaller error some of the time. However, if you pay attention to the
risk and reward, and to the tendencies of your opponents, you can use
bad doubles and failures to double to provoke far worse errors.
A mathematical treatment of this ... is insufficient. The problem is
that mathematically similar positions in terms of volatility, equity,
and gammon rates may differ tremendously in complexity and psychology.
There are some positions in which you need only 5% passes to "justify" a
double, but "no one" would pass: you can estimate that your opponent has
less than a 1% chance of passing, and indeed, you may have no market
In other positions, you may need 25% passes, and you will find them.
Within classes of positions, the percentage of mistakes necessary is
meaningful, but immediate errors need to be weighed against potential
I recently blundered to get an error rate of 5.8 mppm, with 5.0 mppm
coming from two doubles, one somewhat bad and one truly hideous.
This provoked an error rate of over 30 mppm from a player rated over
1900 on FIBS, mainly from two extremely bad passes.
The key was:
1) Timing. I don't mean playable pips. I mean seconds, and fractions of
a second. I don't want to elaborate now, but there is good reason that
there are elaborate rules regarding timing in bridge, to try to avoid
passing illicit information, and I think these rules are insufficient,
and must be combined with ethics. Does anyone have a good reference to
material written on this for poker?
2) After the first bad pass, the second double was much more reasonable.
It aimed for a bad pass, and it didn't give up as much equity as the
first bad pass lost.
3) The second position was confusing, and required proper estimation of
slimy ways to win, and acceptance of instant death a substantial
fraction of the time. Some people can't be sufficiently objective in
such positions. Nevertheless, the second double was a mistake. I didn't
realize the double was quite so bad when I did it. When you plan to make
small errors, you are more likely to make huge errors.
Morris Pearl writes:
I appreciate your insights. On timing, Kit once said that sometimes he
will sit and think for a minute or two about an obvious take or pass,
just to try to give the impression that it is a closer decision. I
assume that this is the kind of thing you are thinking about? What I was
actually thinking about with my original query was the match equity
Say the score is 2-away, 2-away. I am playing against someone who (for
whatever reason) I think plays better than I do. Assume that I have a
small advantage, and there is some joker with which I could lose my
Now, the MET (Kit's) starts out: 50%, 70%, however, because my opponent
is the world champion, I feel that it should be more like 45%, 55%.
In that case it could make sense to turn the cube and play for the match
with an advantage, then to wait, and have a small chance of losing my
market, and end up with less match equity.
Douglas Zare writes:
If you think your opponent is stronger, and instead of winning 70% from
Crawford 2-away, you would win 55%, then your notion of market loser
should change. You would lose your market when your winning chances
exceed 55%! You really ought to double almost immediately.
Ordinarily, you gain when your opponent passes a take, but that would
mean that you would get your stronger opponent to pass something you
would win less than 55% of the time. It's hard to imagine, as that is a
quarter of the advantage you are supposed to need in order to get a
In a complicated position, you might realize that you are lost, or that
you will not be able to extract enough equity from it.
Suppose you have a great backgame with 3 points, and your opponent's
position is getting brittle. However, you know that you haven't studied
containment positions, and with so many checkers back your offense is
imperfect, and you don't think you can get close to the full equity out
of the position. If you somehow know that the position is worth 65%, but
that you would only win 50%, then you might aim for a bad pass, in order
to improve your equity to 55%. I think few human players would want to
pass against a backgame before leaving a shot, though.
I think it is more important to focus on how to exploit mistakes of
weaker players rather than covering up your own mistakes against
stronger players. The standard method at 2-away 2-away is to delay the
double, risking a market loss, until you get to a confusing position
with perhaps a lot of gammon wins but only 60% wins, and your opponent
may pass, giving up a huge chunk of equity.
Another method at 2-away 2-away would be to pass when you have 35%
winning chances in the position (taking into account skill differences),
but feel that you would win more than 35% from Crawford 2-away. Note
that this is the opposite side of what I described in the first
The stronger player's take point is higher, so to avoid market losers
the weaker player must double even sooner. These issues show up at other
scores, but they are less clear there. Walter Trice and Jake Jacobs
wrote a book on asymmetric match equity tables, "Can a Fish Taste Twice
as Good?" I haven't yet gone through enough details to incorporate their
work into my game, though. I just hope I'm getting it right.
- Against a weaker opponent (Kit Woolsey, July 1994)
- Closed board cube decisions (Dan Pelton+, Jan 2009)
- Cube concepts (Peter Bell, Aug 1995)
- Early game blitzes (kruidenbuiltje, Jan 2011)
- Early-late ratio (Tom Keith, Sept 2003)
- Endgame close out: Michael's 432 rule (Michael Bo Hansen+, Feb 1998)
- Endgame close out: Spleischft formula (Simon Larsen, Sept 1999)
- Endgame closeout: win percentages (David Rubin+, Oct 2010)
- Evaluating the position (Daniel Murphy, Feb 2001)
- Evaluating the position (Daniel Murphy, Mar 2000)
- How does rake affect cube actions? (Paul Epstein+, Sept 2005)
- How to use the doubling cube (Michael J. Zehr, Nov 1993)
- Liveliness of the cube (Kit Woolsey, Apr 1997)
- PRAT--Position, Race, and Threats (Alan Webb, Feb 2001)
- Playing your opponent (Morris Pearl+, Jan 2002)
- References (Chuck Bower, Nov 1997)
- Robertie's rule (Chuck Bower, Sept 2006)
- Rough guidelines (Michael J. Zehr, Dec 1993)
- Tells (Tad Bright+, Nov 2003)
- The take/pass decision (Otis+, Aug 2007)
- Too good to double (Michael J. Zehr, May 1997)
- Too good to double--Janowski's formula (Chuck Bower, Jan 1997)
- Value of an ace-point game (Raccoon+, June 2006)
- Value of an ace-point game (Øystein Johansen, Aug 2000)
- Volatility (Chuck Bower, Oct 1998)
- Volatility (Kit Woolsey, Sept 1996)
- When to accept a double (Daniel Murphy+, Feb 2001)
- When to beaver (Walter Trice, Aug 1999)
- When to double (Kit Woolsey, Nov 1994)
- With the Jacoby rule (KL Gerber+, Nov 2002)
- With the Jacoby rule (Gary Wong, Dec 1997)
- Woolsey's law (PersianLord+, Mar 2008)
- Woolsey's law (Kit Woolsey, Sept 1996)
- Words of wisdom (Chris C., Dec 2003)