Occasionally, I find a post with a Nactation that has been superseded, or has an alternate form. Such is the case with the 31P-41S-44 position discussed in this thread.
In this position, Nack used capital D (Down) as the Nactation for 24/16* 13/9(2). It's an example of assumptive Nactation. The obvious part of the play, the hit on the 16pt, is assumed, and the letter D describes the other part of the move, 13/9(2). In October 2011, Nack announced a comprehensive system for nactating doublets without needing to rely on assumption. The system is described in the post entitled Nactation of Doublets (complete table). Under these rules, the move 24/16* 13/9(2) can be nactated as B (Both). It is in the B family because two of the four 4s are played on the far side of the board, and the other two are played down. See the table below. | ||||||||
| Traditional Notation | Far 2 | Down 2 | Jump 0 | Inside 0 | Hits on These Points (more is better) (higher is better) | Owned Points Not Held by All Members in Family (more is better) (closer to 6pt is better) | Blot and Spare Destinations (closer to 6pt is better) (outer board: farther is better) | Nactation |
|---|---|---|---|---|---|---|---|---|
| 24/16*, 13/9(2) | 24/20 24/16* | 13/9 13/9 | 16pt* | 16pt | B | |||
| 24/20(2), 13/9(2) | 24/20 24/20 | 13/9 13/9 | 20pt | b |
*This is the deciding criterion.
| Incidentally, in the same position, the play 24/16* 6/2*(2) can now be nactated E (Each). The E family has six members, each of which plays two 4s on the far side, and two 4s in the home board. It is an interesting Nactation to examine, because in brings into play the hitting exception in the home board. Anywhere else, hitting outranks making or keeping points. In the home board, however, making or retaining points outranks any hit, anywhere on the board.
Two members of the E family make the 2pt. The fact that they also hit is incidental. These two plays add a new point to the home board, and are therefore ranked first and second in the family. A second pair of moves switch points, giving up the 5pt in order to make the 1pt. These two plays maintain Blue's holding of two inside points, and are ranked third and fourth in the family. The last two members of the E family give up the 5pt, but do not make the 1pt. These two plays leave Blue with only one point inside, and rank fifth and sixth in the family. On the far side of the board, members of the E family must either hit, 24/16*, or point, 24/20(2). Hitting – on the far side of the board – ranks higher. |
| Traditional Notation | Far 2 | Down 0 | Jump 0 | Inside 2 | Hits on These Points (more is better) (higher is better) | Owned Points Not Held by All Members in Family (more is better) (closer to 6pt is better) | Blot and Spare Destinations (closer to 6pt is better) (outer board: farther is better) | Nactation |
|---|---|---|---|---|---|---|---|---|
| 24/16*, 6/2*(2) | 24/20 20/16* | 6/2* 6/2 | 2pt 16pt | 2pt 5pt | 16pt | E | ||
| 24/20(2), 6/2*(2) | 24/20 24/20 | 6/2* 6/2 | 2pt | 2pt 5pt 20pt | e | |||
| 24/16*, 5/1*(2) | 24/20 20/16* | 5/1* 5/1 | 1pt 16pt | 1pt | 16pt | E | ||
| 24/20(2), 5/1(2)* | 24/20 24/20 | 5/1* 5/1 | 1pt | 1pt 20pt | e | |||
| 24/16*, 6/2*, 5/1* | 24/20 20/16* | 6/2* 5/1* | 1pt 2pt 16pt | 1pt 2pt 16pt | E | |||
| 24/20(2), 6/2*, 5/1* | 24/20 24/20 | 6/2* 5/1* | 1pt 2pt | 20pt | 1pt 2pt | e |
| See how the exception comes into play. Even though hitting is the first part of Hit/Most/Six, the play that makes the most hits only ranks 5th in the family! Mike |