Strategy--Checker play

Forum Archive : Strategy--Checker play

Late loose hits

From:   Douglas Zare
Date:   31 August 2007
Subject:   10% rule in Lamford's Improve Your Backgammon
Forum:   GammOnLine

I'm writing an article on late loose hits. For example, your opponent
breaks a high anchor, and you are considering hitting loose or trying to
race home. I have seen a reference to a 10% rule in Lamford's Improve Your
Backgammon. Unfortunately, I don't have a copy yet. Could anyone who does
summarize what he says? Specifically,

  * Does he cite anyone else, or does he say that he came up with it?

  * In exactly what context are you supposed to use it?  E.g., what quality
    of offense is your opponent supposed to have?

  * Does he account for wasted pips?

I'll send a copy of my article to anyone who helps.  Thanks,

Douglas Zare

Adam Tansley  writes:

The rule Paul proposes is that in a situation where your opponent has run
from his anchor, and you have an opportunity to hit loose, you should do so
if after the safe play you are ahead in the race by less than 10%. He gives
a few examples, one of which is:

    X to play 5-1.

     24  23  22  21  20  19      18  17  16  15  14  13
    |     O   O   O   O   O |   | O                     |
    |     O   O   O   O   O |   |                       |
    |             O   O   O |   |                       |
    |                       |   |                       |
    |                       |   |                       |
    |                       |   |                       |
    |                     X |   | X   X                 |
    |     X   X   X       X |   | X   X                 |
    |     X   X   X   O   X |   | X   X                 |
      1   2   3   4   5   6       7   8   9  10  11  12

Here he says you should play 8/3, 6/5* because the lead after 7/1 is
insufficient. He gives other examples where you should play safe.

He doesn't say who came up with this, but I believe he did. He makes no
mention of wastage, but this could easily be included in the pip counts.


Fabrice Liardet  writes:

In addition to what tansley said, I can add that :

  * I agree with tansley, although no mention is made of the source of that
    rule, the context makes quite clear that Lamford came up with this on
    his own, using Snowie to benchmark the positions as he did throughout
    the first part of the book. There is a thanks part at the beginning of
    the book, which quotes nobody except Simon Gasquoine, and only about
    the match equity part. On the other hand, it is quite verbose about

  * All his examples show a perfect or near perfect offense for the
    opponent. Again it is implicit ("The basic guideline in this type of
    position...") but clear that he supposes a perfect offense.

  * The rule is supposed to hold with cube possession, which sounds kind of
    strange (doesn't those kind of positions happen most often after the
    opponent just broke his anchor?). Actually I didn't notice this
    important point until now. Lamford mentions that the cube possession
    favours the racing play, but not by how much. Hitting must be much
    better when the opponent owns the cube.

Sure it is an over-simple rule, but already a useful one, because those
decisions are very tough to evaluate. So I am very interested in your
future article!

Marty Storer  writes:

A key aspect of the position is the degree of blockage against the lone
back checker. The position cited by tansley had three points in front of
the back checker. The rule would no doubt change if there were four points
in front of it, or five.

Douglas Zare  writes:

Thanks to all who helped. The article is up on GammonVillage. A draft
version is here:

I investigated a different class of positions than Lamford did.

Douglas Zare
Did you find the information in this article useful?          

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Strategy--Checker play

Avoiding major oversights  (Chuck Bower+, Mar 2008) 
Bearing off with contact  (Walter Trice, Dec 1999) 
Bearing off with contact  (Daniel Murphy, Mar 1998)  [Long message]
Blitzing strategy  (Michael J. Zehr, July 1997) 
Blitzing strategy  (Fredrik Dahl, July 1997) 
Blitzing technique  (Albert Silver+, July 2003)  [GammOnLine forum]
Breaking anchor  (abc, Mar 2004) 
Breaking contact  (Alan Webb+, Oct 1999) 
Coming under the gun  (Kit Woolsey, July 1996) 
Common errors  (David Levy, Oct 2009) 
Containment positions  (Brian Sheppard, July 1998) 
Coup Classique  (Paul Epstein+, Dec 2006) 
Cube ownership considerations  (Kit Woolsey, Apr 1996) 
Cube-influenced checker play  (Rew Francis+, Apr 2003)  [GammOnLine forum]
Defending against a blitz  (Michael J. Zehr, Jan 1995) 
Estimating in volatile situations  (Kit Woolsey, Mar 1997) 
Gammonish positions  (Michael Manolios, Nov 1999) 
Golden point  (Henry Logan+, Nov 2002) 
Hitting loose in your home board  (Douglas Zare, June 2000) 
Holding games  (Casual_Observer, Jan 1999)  [Long message]
How to trap an anchor  (Timothy Chow+, Apr 2010) 
Jacoby rule consideration  (Ron Karr, Nov 1996) 
Kamikaze plays  (christian munk-christensen+, Nov 2010) 
Kleinman Count for bringing checkers home  (Øystein Johansen, Feb 2001) 
Late loose hits  (Douglas Zare+, Aug 2007)  [GammOnLine forum]
Mutual holding game  (Ron Karr, Dec 1996) 
Pay now or pay later?  (Stuart Katz, MD, Nov 1997) 
Pay now or pay later?  (Stephen Turner, Mar 1997) 
Pay now or play later?  (Hank Youngerman+, Sept 1998) 
Play versus a novice  (Courtney S Foster+, Apr 2004)  [GammOnLine forum]
Playing doublets  (Grunty, Jan 2008) 
Playing when opponent has one man back  (Kit Woolsey, May 1995) 
Prime versus prime  (Albert Silver+, Aug 2006)  [GammOnLine forum]
Prime versus prime  (Michael J. Zehr, Mar 1996) 
Saving gammon  (Bill Riles, Oct 2009) 
Saving gammon  (Ron Karr, Dec 1997) 
Splitting your back men  (KL Gerber+, Nov 2002) 
Splitting your back men  (David Montgomery, June 1995) 
Trap play problem  (Brian Sheppard, Feb 1997) 
When in doubt  (Stick+, Apr 2011) 
When to run the last checker  (Stick Rice+, Jan 2009) 
When you can't decide  (John O'Hagan, Oct 2009) 

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