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Nactation Question — Clarifying the B, S and Z Families

Posted By: Taper_Mike
Date: Thursday, 24 November 2011, at 1:54 a.m.

### Is the Following Table Correct?

In a post entitled Nactation: division of labor for B, S, Z, from earlier this year, Nack makes a distinction between doublets and non-doublets for plays in the the B (Both) family. Doublets are covered well in that post, and also in the newer Nactation of Doublets post.

For those unfamiliar with the B (Both) family, it identifies a play that is played half up and half down. For a roll of doublets, half the roll is played on the far side, and the other half is played down, to or within the outer board on the near side.

As the Nactation: Study, Tutorial Supplement, and Annactated Game makes clear, "For non-doublets, B means to split with one number and move within the outer board with the other number." (See the second paragraph under the diagram "Blue to play 41S.") For a non-doublet, the half which is played in the outer board must be played completely within the outer board. Unlike the play of doublets, we are not following the usual definition of "down."

Is there a similar (but opposite) distinction made for S (Split and down) and Z (Reverse split)? In particular, is the following table correct?

Family Non-doublets Doublets
B One die is played on the far side, and one die is played entirely within the outer board on the near side. Two dice are played on the far side, and two dice are played down.
S The larger die is played on the far side, and the smaller die is played from the outer board on the far side into the outer board on the near side. When no such play exists, S can also be used as an alternative to Z. Three dice are played on the far side, and one die is played down. When no such play exists, S can also be used as an alternative to Z.
Z The smaller die is played on the far side, and the larger die is played from the outer board on the far side into the outer board on the near side. One die is played on the far side, and three dice are played down.

In all of these definitions, "down" refers to, "A move made to or within the outer board. The checker must land in the outer board on the near side, but can be moved from any point in either outer board."

A play on the far side of the board means, "The entire move is made on the far side of the board, including entering a checker from the bar. The checker can land anywhere on the far side, from the midpoint on up."

Mike

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