| Nactation | Family | Non-doublets | Doublets |
|---|---|---|---|
| S | Split | The larger die is played on the far side side of the board, including entering a checker from the bar. The smaller die is played into the outer board from the opponent’s outer board. When there are no moves in the S family for a roll of non-doublets, the Convenience Clause allows you to use either S or Z to refer to plays in the Z family. | Three dice are played on the far side of the board, including entering one or more checkers from the bar. One die is played down (i.e., to or within the outer board). |
| Z | Reverse split | The smaller die is played on the far side of the board, including entering a checker from the bar. The larger die is played into the outer board from the opponent’s outer board. | One die is played on the far side of the board, including entering a checker from the bar. Three dice are played down (i.e., to or within the outer board). |
| B | Both | One die (large or small) is played on the far side of the board, including entering a checker from the bar. The other die is played entirely within the outer board (on the near side). | Two dice are played on the far side of the board, including entering one or more checkers from the bar. The other two dice are played down (i.e., to or within the outer board). |
Notes
- When there is more than one play in a given family, the Hit/More/Six Rule is used to rank the members.
- S, Z and B are all areal (i.e., area-based) families. Membership is determined by the areas of the board where checkers are moved. All three families follow the “split-and-down” model. Part of the roll is used to “split,” and the other part is used to play “down” to a destination in the outer board.
- Nactation, by design, uses a broad definition of the term “split.” Any move on the far side of the board is called a split. Sometimes that movement will break a point; sometimes it will not. Sometimes it may even make a point. Those actions are not why a play is called a “split.” The only thing that matters is the area. So long as a movement occurs entirely on the far side of the board, it fits Nactation’s definition of “split.”
                       | |||
| 32S-64H-43, S (Split) = bar/21, 13/10 | |||
| Position ID: 4HPwBSDgc/AAUQ Match ID: cIkRAAAAAAAA | |||
Example 1: 32S-64H-43
In this example, S = bar/21 13/10.
The split portion is played bar/21. The down portion is played 13/10.
      | |||
| 42P-43S-65R-64, S (Split) = 20/10 | |||
| Position ID: mGfwAyDgc+IBIQ Match ID: cAkTAAAAAAAA | |||
Example 2: 42P-43S-65R-64
Here, S = 20/10.
The two checker movements are 20/14 and 14/10. The split portion is played 20/14 (entirely on the far side), while the down portion is played 14/10.
Note that 20/10 cannot be nactated in the R (Run) family. That is because Run requires that all movements occur on the far side of the board, with at least one checker landing somewhere between the 13pt and 17pt.
Mike