Strategy--Checker play

Forum Archive : Strategy--Checker play

Cube-influenced checker play

From:   Rew Francis
Address:   none
Date:   9 April 2003
Subject:   Cube influenced checker play
Forum:   GammOnLine

24  23  22  21  20  19      18  17  16  17  14  13
  102  +---+---+---+---+---+---+---+---+---+---+---+---+---+
       |     O   O   O       O |   | O           O   O   X |
       |     O   O   O       O |   | O           O       X |
       |                     O |   |                     X |
       |                       |   |                     X |
       |                       |   |                       |
       |                       |   |                       |
       |                       |   |                       |
       |                     X |   |                       |
       |                     X |   |     X                 |
       |         X       X   X |   |     X                 |
       |         X   O   X   X |   |     X                 |
  116  +---+---+---+---+---+---+---+---+---+---+---+---+---+
         1   2   3   4   5   6       7   8   9  10  11  12

                     Money Game:  X to play 6-2

Looking at the above position, I wasn't sure what was the best play,
13/5, or 13/7, 6/4*.  I was a bit surprized when I checked it with
snowie3.2, 3-ply and found that the hit was a whopping 0.170 better.

1. 13/7, 6/4*:  0.2% 6.1% 50.8% 49.2% 18.1% 0.5%  Eq.:  0.036
2. 13/5:        0.1% 2.8% 45.6% 54.4%  1.7% 0.1%  Eq.: -0.133 (-0.169)

But looking at the percentages, this didn't make any sense, so I checked
its cubeless evaluation. This evaluation showed that 13/5 was a little
bit better. What accounts for this difference? One thing is quite obvious
for me. The hit makes it more difficult for white to give an efficient
cube, so the cube influence probably favours that move.


Kit Woolsey  writes:

If you look at the percentages, you see that the hitting play wins the game
roughly 5% more often, wins a gammon roughly 3% more often, and loses a
gammon roughly 16% more often. This kind of result shouldn't be too hard to
estimate without the help of a bot -- just look at the position and it
should be clear.

What does all this mean as far as the cube goes? If Blue plays 13/5 and
White gets away, White will have a good lead in the race and will be
closing in on a very efficient cube.

If Blue hits loose and White flunks, now it is Blue who has the efficient
cube. White probably has a pass, but it isn't a monster pass.

If Blue hits loose and White enters without hitting, Blue again has a
reasonably efficient cube (or if he doesn't, he is closing in on one).
White would now have a take, but it would be getting close.

If Blue hits loose and White hits back, White will probably lose his market
by a mile unless Blue rolls a joker.

Thus, 13/5 is more likely to lead to an efficient cube for White, while
the loose hit is more likely to lead to an efficient cube for Blue. If the
cubeless equities of the plays are close, this is sufficient to make the
loose hit very clear.

This position is a very nice prototype for understanding the relationship
of checker play and cube action. It should be carefully studied by all
serious players.

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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