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Nactations of 32D-51$-21

Posted By: Taper_Mike
Date: Thursday, 23 January 2014, at 1:27 a.m.

In Response To: Advanced Backgammon #7 (Igor)

2O ' ' '1X4X '4X ' ' '3O

2X ' ' ' '5O '3O '1O1O4X
Position ID: 0PPgATDgc8oBMA Match ID: cAkFAAAAAAAE

32D-51$-21 — Nactation Key
FamilyNactationTraditional NotationNote
Slot$ 13/11, 6/5 13/11 6/5 adds a new point, and slots the best point.
Alternate slot% 11/10, 6/4 11/10 6/4 also adds a new point, but slotting the 4pt ranks below slotting the 5pt.
BothB 24/22, 11/10 By the More Points convention, making the 10pt beats any play that does not make a point.
DownD 11/9, 10/9 By the 6pt Convention, making the 9pt outranks making either the 10pt or 11pt.
Downd 13/10 By the 6pt Convention, making the 10pt outranks making the 11pt.
DownD 13/11, 10/9 Making the 11pt and slotting the 9pt outranks making the 11pt and slotting the 8pt.
Downd 13/11, 8/7 By the wrinkle in the 6pt Convention, a blot on 7pt ranks below a blot on the 9pt.
NearN 11/10, 6/4 In the Near family, one die is played to a destination in one’s outer board, while the other is moved entirely within the inner board.

Using Hit-More-Six To Rank the D (Down) Family

Moves in the D (Down) family play both dice to destinations in the the roller’s outer board. In the case of 32D-51$-21 (diagrammed above), there are many ways to do that. To determine which is assigned the capital letter, the members of the D family are ranked using the Hit-More-Six Rule.

The Hit Convention is the top priority. If any member of the Down family hit a checker, it would rank atop the family, and be assigned the capital letter. Since, however, there are no hitting plays in this position, ranking proceeds by next considering the More Points Convention.

Moves that result in the largest number of made points are preferred under the More Points Convention. In this position, therefore, the plays that make either the 9pt, 10pt, or the 11pt rank higher than plays such as 11/8 that do not make a new point. There are four such plays:

  • Make 9pt: 11/9, 10/9
  • Make 10pt: 13/10
  • Make 11pt: 13/11, 10/9
  • Make 11pt: 13/11, 8/7

Under the More Points Convention, all these plays are tied. To break the tie, one next considers the 6pt Convention.

There are two parts to the 6pt Convention. The first considers how close made points are to the 6pt. Owned points are preferred when they are closer to the 6pt. In the event of a tie, the second part of the 6pt Convention examines the landing spots of the blots and spares moved in a play.

Of the four moves above, only one makes the 9pt. It, therefore, outranks the others, and is assigned the capital letter. Of the remaining three, only one makes the 10pt. It ranks second and is assigned lower case letter. The final two both make the 11pt and are tied under the first part of the 6pt Convention.

To break the tie, compare the destinations of the blots that are moved in the two plays. In one’s outer board, blots and spares are preferred when they are farther from the 6pt. That’s the so-called wrinkle in the 6pt Convention. In any other quadrant, blots and spares are preferred when they are closer to the 6pt. By this wrinkle, a blot on the 9pt is better than one on the 7pt.

  • D (Down) = 11/9, 10/9
  • d (down) = 13/10
  • D (Down) = 13/11, 10/9
  • d (down) = 13/11, 8/7



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