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Wild or not #1 (54S-51H-31)

Posted By: Nack Ballard
Date: Sunday, 6 April 2014, at 5:56 a.m.

In Response To: Wild or not #1 (54S-51H-31) (rambiz)





White is Player 2

score: 0
pip: 161
Unlimited Game
Jacoby Beaver
pip: 163
score: 0

Blue is Player 1
XGID=-b----E-D---dD---d-da---AA:0:0:1:13:0:0:3:0:10

54S-51H-31


Isn't this position covered in the opening book by Nack and Paul Weaver? Do they cover all 3rd roll 31s in their book?

At the end of the first page of the preface (page xi), Paul and I summarize the three feature chapters of Backgammon Openings (reviews here). I've copied the text below.

  1. Chapter 1: These four pages teach much more than how to play an opening 31! We dissect the positive attributes of the 5pt, compare the 7pt to the 5pt, and show positions that are often misplayed because the value of the 5pt is underestimated.
  2. Chapter 2: We discuss how 31 should be played as a response to all standard (and some non-standard) opening plays. There are interesting and challenging decisions with 31 as early as the second roll.
  3. Chapter 3: We introduce the study of third roll positions, examining how 31 should be played in many difficult situations. New concepts are presented that apply not only to third roll positions, but also to later stages of the game.

Chapter 3, by far the longest, has six subdivisions (each having several positions): Hitting in the Inner board, Hitting in the Outer Board, Hitting on the Opponent's Side, Anchoring, Splitting, and Slotting.

As Tim mentioned, we did not attempt to cover all third roll positions with 31, just the most interesting, educational and representative ones. We excluded third roll positions where the best move was patently obvious (otherwise there would have been position after position where one should boringly make the 5pt), and excluded positions where the top move was tied (except for footnote diagrams/variants). We basically aimed to cover all potential surprises where significant equity can be saved or gained by knowing the right play.

XG did not yet exist when Backgammon Openings was written, but according to our rollouts at the time, the top two moves for 54S-51H-31 were borderline tied / very close (around .01 apart), and it did not make the cut. In most cases, we strove to help the reader correct his or her errors of .02 or greater.

Granted, there are two moves for 54S-51H-31 one might consider playing that are (as I recall) roughly -.04, but if you make a study of the subdivisions devoted to splitting (especially) and slotting, themes that carry over to other third roll positions (and even into the middle game, and with other rolls) will jump out. For example, avoid coming down once the midpoint is already reduced (as it is here).

Playing "wild" (slotting while loosely split -- anchorless) is generally nixed with a third-roll 31 because of the automatic lack of duplication, though position A222 (63S-66B-31) is a notable exception, the startling revelation included in Neil's excellent review.

Contrasting position pairs (on facing pages) are a highly instructive format (discussed in detail on pages 106109), and, as Tim indicated, most of the feature (non-footnote) positions in Backgammon Openings were selected to fit that design. However, there are a few stand-alone positions, and a few non-contrasting sets of positions (such as 64S-66B-31, 63S-66B-31, 62S-66B-31) that were chosen to emphasize important concepts.

Julian Fetterlein's favorite position pair, and mine, is diagrammed here. One pip changes a blunder one way into a blunder the other way.

Nack

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