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NG Opening 53

Posted By: Nack Ballard
Date: Thursday, 6 May 2010, at 5:53 a.m.

In Response To: NG Opening 53 (Nack Ballard)

Nackgammon (NG) Opening Position
How do you play NG opening 53?

Opinion was divided. Of the eight respondents, a majority of five preferred Q (Quadruple split, 24/21 23/18), in order to "get the back men moving and establish a forward anchor somewhere."

A minority of three preferred Z (reverse split, 23/20 13/8). Petter recalled from a Kit Woolsey article on Nackgammon that it is valuable to add a spare to the 8pt. Matt agrees -- that he needs that spare for a four-prime because he (Matt) usually rolls double 1s on the following roll.

Two respondents supported z (minor reverse split, 24/21 13/8) as their close second choice behind Z.

It seems that nobody wanted to "fall for" P (Point, 8/3 6/3), which makes the too-deep 3pt. Myshlev articulated: "Those checkers are almost completely out of play in what can easily turn into a long and complicated game." Nevertheless, according to all three bots, P is in close second place.

It's not clear to what extent we can trust the bots to properly play positions with four (or more) checkers back, but here are the results:

Snowie .. [Z P14 z19] 10k
GnuBG .. [Z P8.5 z21 Q36 R40 r44 S65 U67 D135 $145] 62k 20kzQ 10kRr 5k
XG 3-ply [Z P12 z15 R41 Q41 r49 S58 U62] 62k 31kRQr 15k

Composite [Z P11 z18 Q39 R41 r47 S61 U64 D135 $145]

Key: Z = reverse split (23/20 13/8), P = Point (8/3 6/3), z = reverse split (24/21 13/8), Q = Quad-split (24/21 23/18), R = Run 23/15, r = run 24/16, S = Split (23/18 13/10), U = Up (23/20 23/18), D = Down (13/10 13/8), $ = Slot (13/5).

Error sizes are in thousandths. After the brackets, the number of trials (in thousands, rounded down) is shown. For example, "[Z P14 z19] 10k" means that Z is best, P is -.014 and z is -.019, after 10000+ trials.

Here are the top eight opening 53 plays, in order of bot ranking:

Blue played Z, which is best

Blue played P, which is -.011 but best at GG

Blue played z, which is -.018	186

Blue played Q, which is -.039

Blue played R, which is -.041

Blue played r, which is -.047

Blue played S, which is -.061

Blue played U, which is -.064

For other scores (where d = DMP, s = GS, and g = GG), the GnuBG results are:

d [Z Q8 z12 R13 S19 U20 r25] 20k
s [Z z16 P17 Q32 R35 r37 S38 U46] 12kZzP 5k
g [P Z10 z24 Q29 R35 S36 U42] 12k 5kRU

The daily "Nackblitz" tournaments on Gridgammon (and maybe elsewhere) consist primarily of one-point matches (DMP). At that score, Z and Q (all eight respondents chose one or the other) are the top two plays.

Acknowledgment and gratitude to Ken Bame for dedicating so much of his CPU to Gnu and XG Nackgammon rollouts.

Nack

Messages In This Thread

• NG Opening 53
  Nack Ballard -- Monday, 19 April 2010, at 8:38 a.m.
  • NG Opening 53
    Christian Munk-Christensen -- Monday, 19 April 2010, at 9:01 a.m.
  • NG Opening 53
    Matt Cohn-Geier -- Monday, 19 April 2010, at 9:05 a.m.
    • NG Opening 53
      Casper van der Tak -- Monday, 19 April 2010, at 10:33 a.m.
    • NG Opening 53
      Christian Munk-Christensen -- Monday, 19 April 2010, at 1:50 p.m.
      • NG Opening 53
        Chiva Tafazzoli -- Monday, 19 April 2010, at 3:10 p.m.
      • NG Opening 53
        Matt Cohn-Geier -- Monday, 19 April 2010, at 4:58 p.m.
  • NG Opening 53
    Chiva Tafazzoli -- Monday, 19 April 2010, at 10:29 a.m.
  • NG Opening 53
    myshlev -- Monday, 19 April 2010, at 10:38 a.m.
  • NG Opening 53
    Ian Shaw -- Monday, 19 April 2010, at 12:23 p.m.
  • NG Opening 53
    David Rockwell -- Monday, 19 April 2010, at 1:44 p.m.
  • NG Opening 53
    Petter Bengtsson -- Tuesday, 20 April 2010, at 8:48 a.m.
  • NG Opening 53
    Nack Ballard -- Thursday, 6 May 2010, at 5:53 a.m.
    • NG Opening 53
      Casper van der Tak -- Thursday, 6 May 2010, at 6:08 a.m.
      • NG Opening 53
        Nack Ballard -- Thursday, 6 May 2010, at 7:05 a.m.
        • NG Opening 53
          Casper van der Tak -- Thursday, 6 May 2010, at 7:11 a.m.
    • NG Opening 53
      Matt Cohn-Geier -- Thursday, 6 May 2010, at 6:12 a.m.
      • NG Opening 53
        Nack Ballard -- Thursday, 6 May 2010, at 7:13 a.m.
        • NG Opening 53
          Matt Cohn-Geier -- Thursday, 6 May 2010, at 9:11 a.m.
    • NG Opening 53
      lenny -- Thursday, 6 May 2010, at 6:25 a.m.
      • NG Opening 53
        Nack Ballard -- Thursday, 6 May 2010, at 8:07 p.m.