Let me first announce this will be a work in progress trying to refine what I will eventually post on my site for people who need to know what all those funny little symbols mean. Also, some of this is directly taken from Nack & Paul's upcoming book (with permission) but I'm not going to identify which part is me and which part is from the book, if it sounds intelligent, well thought out and structured, attribute it to them, if it sounds like some jackass drinking Crown & Coke at home on his computer at 1am on a Friday night because he was too lazy to go out...well, on with it.
The term 'nactation' is an amalgamation of "Nack" (its inventor) and "action notation". It is a system of describing plays. Nactation uses terms for actions (run, split, slot ...) and directions (up, down ...) that are commonly used to convey checker movements.
Run: Moving a back checker to the opponent's outer board.
In traditional notation, "24/15" means to move from the 24pt to the 15pt, but to be complete one must also mention whether the roll is 63 or 54. Using nactation, the roll and the action are combined into the term "63-run". This would be abbreviated as 63R where R stands for Run. In the diagram below we would differentiate between an opening 54 played 24/15 by employing nactation, 54R, or similarly for an opening 63 played 24/15, 63R.
| 167 |                        |
| 158 |
Point: Making or covering a point. The notation for Blue's play with an opening 64 as in the diagram below making the 2pt is "8/2 6/2." The nactation is "64-point". This would be transcribed as 64P where P stands for Point.
| 167 |    |
| 157 |
Down: From the midpoint to the outer board. In the diagram below Blue played "43-down" which is abbreviated 43D where D stands for Down.
"Down" can also refer to moving one checker; e.g., 13/8 is "5-down" (one die) or "41-down" (two dice). Note 13/8 with 32 is "32-stack" to distinguish it from "32-down" (13/11 13/10).
| 167 |    |
| 160 |
Up: Advancing back checkers. In the diagram below Blue played "43-up" which we transcribe 43U.
"Up" also refers to moving one back checker; for example, 24/21 is "3-up" (one die) or "21-up" (two dice). Note 24/23 24/22 is "21-two-up" to distinguish it from "21-up".
| 167 | |
| 160 |
Split: The classical definition of "split" is to break an anchor with the number on one die (similar but not identical to the meaning of "up").
Nactation adds a definition for "split", composed of two actions: to break the 24pt anchor (with one die) and to play down (with the other die) in the same move.
In the diagram below, Blue played "43-split". By convention, the first digit (the 4 here) is the number used to split the back checkers and the second digit (the 3 here) is the number that was played down from the midpoint.
Pay careful attention when transcribing this, when the first or larger digit (the 4 here) is used to split we'd transcribe it 43S where S stands for Split.
| 167 |  |
| 160 |
In the next diagram, Blue split with his 3 and played his 4 down. Observing the split-number-first convention mentioned in the last paragraph above, Blue played "34-split". (also referred to as "43-reverse") This is the reverse split where you split with the smaller die (3 here) and bring the larger die (4 here) down. Transcribed it would be 43Z where Z stands for Reverse. Try not to confuse the last two examples, initially it may be irksome but I promise you once you've mastered nactation it makes discussion of the opening (or labeling files, etc...) much easier.
| 167 | |
| 160 |
This is where I end the first part of nactation. I will let you digest this small portion which actually covers the opening two moves as you will need it for navigation on my site, some of which you've probably grown accustomed to since you are on these forums. By the end of the weekend I will branch off into nactation through the third roll of the game. Any and all comments/suggestions are welcome. For more information on Nack/Paul's Backgammon Openings, Book A and the rest of the project check out Nack's Site. Always looking for more people to help rollout positions too.
Stick