Strategy--Checker play

Forum Archive : Strategy--Checker play

Mutual holding game

From:   Ron Karr
Date:   9 December 1996
Subject:   Re: A position

Robert-Jan Veldhuizen wrote:
> Here is another position from my match against MMagnani. It was one of
> those games in which neither player gets "lucky" rolls and I found almost
> every move in the game a tough choice. Maybe some players can shed some
> light on this position and, more generally, what sort of "long-term"
> goals one should try for in this sort of position (if there are any...).
>    +-1--2--3--4--5--6--------7--8--9-10-11-12-+ O: MMagnani - score: 1
>    |    O  X        O |   |  O  O           X |
>    |    O  X        O |   |  O  O           X |
>    |                O |   |                   |
>    |                O |   |                   |
>    |                O |   |                   |
>    |                  |BAR|                   |v    3-point match
>    |                  |   |                   |
>    |                X |   |     X             |
>    |                X |   |     X             |
>    |          X  O  X |   |     X             |
>    | O  O     X  O  X |   |     X  X          |
>    +24-23-22-21-20-19-------18-17-16-15-14-13-+ X: Zorba - score: 0
>    BAR: O-0 X-0   OFF: O-0 X-0   Cube: 1  turn: Zorba
> It's your turn. Please roll or double
> Pipcounts: You 143   MMagnani 151
> You roll 4 and 3.
> Please move 2 pieces.
> > 16 19 19 23

This position qualifies as a "mutual holding game", where both sides
have advanced anchors.  The leader in the race (pip count) is usually at
an advantage, IF he can manage to clear the anchor without being
attacked (usually by rolling doubles).  In this position, you are at an
advantage, since you are ahead in the race.  Also, O has 2 additional
men back, which means even if he catches up by rolling big doubles, he
can't escape everyone.

Your anchor is not as advanced as O's, since you're back on his 3 point,
which is a disadvantage for you. However, he won't be able to fill in
his 4 and 5 points easily, so it may not be too hard for you to escape
eventually.  Also, you have control of the outfield.  He will be trying
to run his spare back men out (keeping the 20 point), and you will have
the chance to hit him.

> So, I moved 16-19 19-23*. One hit, one blot on my 2pt.
> How about 17-21 21-24* ? Leaves an extra blot/builder on the 16pt. Is
> this better or worse ?

The problem with both hitting plays is that they risk more than they
stand to gain.  If hit, you lose 23+ pips in the race, while only
setting O back 1 or 2 pips.  If you get lucky and are missed, then cover
the point, you still haven't accomplished that much, since O has an
anchor on your 5 point.  Since you are ahead in the race, it's better to
play safe if possible.

> I guess the safe 16-19 17-21 is too cramped ?

Actually, it's fairly flexible.  Combinations of odd numbers make your 3
point next time; combinations of even numbers make your 2 point.  Worst
case, you might have to hit loose next time.

> And I didn't dare to think about breaking my midpoint here, I hope I was
> right there.

I would definitely think about breaking the midpoint, since you can make
your 9 point by doing so.  The 9 point is very valuable as a blocking
point in this position.  And the midpoint isn't so crucial, since O no
longer has his midpoint.  However, if you play 12/16, then you're forced
to leave a shot with the 3.

If you are interested in what Jellyfish says (Level 7):

17-21 16-19             15.4
12-16 12-15         14.1
12-16 19-22             14.0
17-24*                  10.9
16-23*                  10.1

The plays are fairly close, which is usually the case in this type of
position.  However, it appears that the safe play is best, followed by
the plays that make your 9 point.

Did you find the information in this article useful?          

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


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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