Strategy--Checker play

 Prime versus prime

 From: Michael J. Zehr Address: tada@athena.mit.edu Date: 19 March 1996 Subject: Re: Priming game question Forum: rec.games.backgammon Google: 4imu32\$go7@senator-bedfellow.MIT.EDU

```Jason A. Nordwick writes:
> >
> >    +-1--2--3--4--5--6--------7--8--9-10-11-12-+ O: fiete - score: 3
> >    | O     X  O  O  O |   |  O  O             |
> >    | O        O  O  O |   |  O  O             |    BAR: 0  OFF: 0
> >    | O                |   |                   |
> >    | O                |   |                   |
> >    |                  |BAR|                   |v    5-point match
> >    |                  |   |                   |    Your roll
> >    |             X  X |   |                   |    Cube: 2
> >    |       X  X  X  X |   |     X             |    BAR: 1  OFF: 0
> >    |    O  X  X  X  X | X |  X  X             |
> >    +24-23-22-21-20-19-------18-17-16-15-14-13-+ X: You - score: 4
> >
> > You roll 3 and 6.
> > How should one play the 6 in this position ? And why ?
>
> I'm just learning this game, so could someone please give me some
> feedback on my line of analysis? thanks... now the answer:
>
> with board strength fairly even and having two back-men versus one,
> Magriel (sp?) says play agressive. so i play bar/3,17/23*.  here's why:

I believe you're getting into trouble here by applying a rule intended
for early and mid game positions to a prime-vs-prime position.  This
kind of position is one of the most complicated position variations.
They still aren't very well understood, though we're making progress.

In very broad general terms, timing is probably th emost important
factor in prime vs prime.  (Timing meaning how long you can roll without
having to break an important point.)  If you're on the bar, many of your
rolls you don't have to play, so you're improving your timing.

So hitting your opponent when you have a better board might be the wrong
idea.

(In prime vs. prime you tend to want to attack and close out your
opponent only if you're pretty sure you can escape.  With two behind a
5 prime, escape isn't at all a sure thing, so you don't necessarily want
to attack.)

> all the one hit scenarios are fairly liveable: you engage in
> a blot hitting contest and you either get your back men loose giving

I disagree with this.  If you played 8-2* and your opponent hits back
you have three men behind a 4 or 5 prime and he has 1 man behind a 4
prime.  (If he rolled a 1-6, he's past the prime anyway.)

And what is your follow play if he *doesn't* hit.  You need a 6 to cover
and a 6 to run, so how do you play a 62, for example?

> bar/2,18/24 -- too passive, if he gets out your gone.  he has the one
> and two pts to thrown pieces into (a 3pt backgame doesn't sound like a
> winner to me... hmmm... are their books/charts out there that show the
> likelyhood of hitting in a backgame situation? it seems to me that a
> 2-3pt backgame wouldbe just better than a 1-3pt backgame with the
> further forward pieces getting the worse).

"Backgame" refers to having more than one anchor in your opponent's
board (among other things).  Your side isn't going to be playing a
backgame here -- it will be playing a 3pt anchor game, which doesn't
generate a lot of shots, but it doesn't get gammoned much either and it
still has some racing chances.

I think there are two real keys to evaluating this position:  If you
don't hit and your opponent rolls a 5, you're in pretty big trouble if
you had a blot on the bar point or not.  You're in worse trouble if you
were hit when he escaped than if you weren't hit.

If your opponent doesn't roll a 5, your opponent is in much worse shape
if he's on the 2pt than if he's on the bar, particularly if you hold an
anchor on the 3pt.

In short, I agree with the other poster who selected 7-1 as their choice
in moves.  But... as I said before, prime vs. prime games tend to be the
least understood games, and even experts get into big disagreements over

-michael j zehr
```

### 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)
Blitzing strategy  (Michael J. Zehr, July 1997)
Blitzing strategy  (Fredrik Dahl, July 1997)
Blitzing technique  (Albert Silver+, July 2003)
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)
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)
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)
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)
Playing doublets  (Grunty, Jan 2008)
Playing when opponent has one man back  (Kit Woolsey, May 1995)
Prime versus prime  (Albert Silver+, Aug 2006)
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)