Opening Rolls

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Nactation overview

From:   Nack Ballard
Date:   10 October 2009
Subject:   Nactation Overview by Nack Ballard
Forum: Forums

Ever since learning backgammon, Ive been fascinated with the theory of
early game moves. Many years ago, I started working on a system of notation
that would convey early game plays with a single letter/character.
Nactation (short for Nack-action-notation) was founded on the principle
that characters (letters, symbols) should be

(1) User-friendly.
(2) Efficient.

To satisfy (1) user-friendliness, I wanted the letters to be as associable,
and therefore memorable, as possible. Most characters are the first letter
of the word that describes its action: Some examples are S, R, P, H, D and
U, which stand for Split, Run, Point, Hit, Down and Up, respectively.

Additional letters were created to serve the basic ones. For example, S is
the first letter of Split, and splitting plays (which are fully defined as
splitting with one number on the die and coming down with the other number)
are designated by S as much as possible. The letter Z (which looks like a
backwards S) stands for reverse split, was created to serve S, and is not
intended to get equal time. It is only when there would otherwise be an
ambiguity that it is necessary to resort to Z. (In the case of modern
opening plays, this includes only 43- played 24/21, 13/9 instead of 24/20,
13/10, and perhaps 32 played 24/22, 13/10 instead of 24/21, 13/11.)

It is easier to remember that S relates to a Split than that Z relates to a
Split; its that simple. At the outset, I did contemplate many other S/Z
schemes, including the one discussed at length in the recent S/Z thread,
but I put a premium on user-friendliness (or at least my perception of it).

When I first learned the game of go, my teacher urged me to picture a big
go stone with straps around its shoulders, digging its feet into the dirt,
leaning forward and strained to its limit to drag an enormous weight, and
that each stone I play on the go board should do that kind of work. I feel
the same way about Nactation letters pulling their weight, which brings us
to their being: (2) efficient.

A common misconception is that Nactations for plays with a given roll
consistently translate to a fixed traditional notation. Not so. To
accomplish that, it would be necessary to have thousands of characters;
even with full integration of lower case, italics, numerals and other
keyboard symbols, there would not be nearly enough to go around.

Consider 21S-65R-54. (This is Nactations way of saying that Black rolled
opening 21 and split with 24/23 13/11, in reply White rolled 65 and ran
24/13, and now Black has 54 to play.) There are two things to notice here.
The first is that the concept of "splitting" is not necessarily confined to
a play that breaks an anchor. It applies more generally to a play that
moves a back checker with one number (and comes down with the other).
Otherwise, new letters would have to be added to express variations on the
same splitting theme and Nactation would be that much harder to learn.

      24  23  22  21  20  19      18  17  16  15  14  13
     | X   X               O |   |     O               X |
     |                     O |   |     O               X |
     |                     O |   |     O               X |
     |                     O |   |                     X |
     |                     O |   |                       |
     |                       |   |                       |  X rolls 5-4
     |                       |   |                     O |
     |                     X |   |                     O |
     |                     X |   |                     O |
     |                     X |   |     X               O |
     |                     X |   |     X               O |
     | O                   X |   |     X           X   O |
       1   2   3   4   5   6       7   8   9  10  11  12

The second thing to notice is that with his 5-4, Black has a choice of two
splitting plays: 23/18, 13/9, and 24/20, 13/8. The first choice moves a
back checker with the larger number (5) and is therefore "S." The second
choice moves a back checker with the smaller number (4) and is therefore
"Z." This means that 24/20, 13/8 (the smaller split) is necessarily
nactated 54Z here, whereas the standard Nactation for 24/20, 13/8 played on
the very first roll of the game is 54S.

Keep in mind that this is as complicated as it gets, and a scenario as
tricky as the one above arises with relative infrequency. When it does, is
it confusing? Perhaps for some, until they let go of their notion that
nactated plays somehow "should" always translate to the same traditional
notations. The system is not designed that way, and if it were it would be
profoundly inefficient. Just remember: S splits with the large number (or
is the only split); if a choice exists, Z splits with the small number.

(If Z is used when there is only one legal splitting play, there is also no
ambiguity -- nothing "wrong" in that sense, but I still recommend S in
these cases. S = Split is easier to remember and I believe it will better
serve those still learning Nactation.)

I am grateful to Stick Rice, who has helped popularize Nactation on a grand
scale, to David Rockwell for his patient explanations to people on this
forum, and to Tim Chow for organizing Sticks opening reply rollout data
into a semi-nactated chart. (My fully nactated, single-letter version of
his chart, freshly updated, can be found at a separate link on Tim's page,

Finally, if you would like to understand Nactation (growing in its use on
this forum), go here:
The explanation is in layers, and Section 1 (only one page) is by far the
most useful: reading that will enable you to interpret most of the
Nactation youll see in bgonline postings. If you get as far as digesting
Section 3 (the BEACON letters for doublets), consider yourself an expert!

-Nack Ballard
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Opening Rolls

At different match scores  (Louis Nardy Pillards, July 2002) 
Average advantage of winning opening roll  (Chuck Bower, Oct 1998) 
Choosing a strategy  (Daniel Murphy, June 2001) 
Early game rule of thumb  (Rich Munitz, Feb 2009) 
Factors to consider  (Kit Woolsey, July 1994) 
How computers play  (Kit Woolsey, Mar 1995)  [Recommended reading]
Magriel's Chapter 5  (Hayden Alfano+, May 2006)  [Long message]
Mloner vs Jellyfish  (Kit Woolsey, Dec 1995) 
Nactating a whole game  (Nack Ballard+, Jan 2011)  [Long message]
Nactation  (Jim Stutz+, June 2010) 
Nactation overview  (Nack Ballard, Oct 2009) 
Nactation--Why use it?  (leobueno+, Jan 2011) 
Opening 1's: Split or slot?  (Douglas Zare, Dec 2003) 
Opening 21: Rollout  (Stick, Mar 2006)  [GammOnLine forum]
Opening 21: Split or slot?  (Dick Adams+, Dec 2003) 
Opening 32: Rollout  (Stick, Feb 2006)  [GammOnLine forum]
Opening 43: In GOL online match  (Raccoon+, Feb 2004)  [GammOnLine forum]
Opening 43: Pros and cons  (Stick+, Jan 2006)  [GammOnLine forum]
Opening 43: Which split is better?  (Peter Backgren+, Aug 2000) 
Opening 43: Which split is better?  (Michael J. Zehr+, Mar 1996) 
Opening 51: Rollout  (Stick, Feb 2006)  [GammOnLine forum]
Opening 52: Merits of splitting  (Peter Bell, Apr 1995) 
Opening 53: Magriel's recommendation  (George Parker+, July 1997)  [Long message]
Opening 53: Split to 21?  (Alex Zamanian, Aug 2000) 
Opening 53: Why make the three point?  (Kit Woolsey+, Feb 1996) 
Opening 6's: Slot the bar point?  (Chuck Bower+, Feb 2000) 
Opening 6's: Slot the bar point?  (David Montgomery, June 1995) 
Opening 62: Could running be best?  (Gary Wong, Sept 1997) 
Opening 62: Split, run, or slot?  (Chuck Bower, May 1997) 
Opening 63: Middle Eastern split?  (Mark+, Apr 2002) 
Opening 63: Slot the four point?  (Dennis Cartwright+, Mar 2002) 
Opening 64: Make the two point?  (William Hill+, Jan 1998) 
Opening 64: Make the two point?  (Darse Billings, Feb 1995) 
Opening 64: Rollout  (Peter Grotrian, Jan 2006)  [GammOnLine forum]
Opening 64: Split to 20?  (Peter Bell, June 1995) 
Opening 64: Three choices  (Brian Sheppard, July 1997) 
Opening 65: Becker on lover's leap  (Jeffrey Spiegler+, Aug 1991) 
Opening 65: Computer rankings  (Chuck Bower, Jan 1997) 
Opening rolls ranked  (Arthur+, Apr 2005) 
Rollouts of opening 21 and replies  (Alexander Nitschke, Oct 1997) 
Rollouts of openings  (Tom Keith+, Jan 2006) 
Rollouts: Expert Backgammon  (Tom Fahland, Aug 1994) 
Rollouts: Jellyfish 3.0  (Midas+, Sept 1997) 
Rollouts: Jellyfish 3.0 level 6  (Chuck Bower, Feb 1999)  [Recommended reading]
Rollouts: Snowie 4.1  (Rene Cerutti, Apr 2004) 
Slotting the four point  (Joe Loria+, Oct 1999) 
Snowie's openers and replies  (rcerutti, Feb 1999)  [Long message]
Splitting versus building  (Dave Slayton+, Aug 2000) 
Splitting versus slotting  (Daniel Murphy, Apr 2001) 
Splitting versus slotting  (Daniel Murphy, Sept 1997) 
Trice's rankings  (Marty Storer, Feb 1992) 

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