Opening Rolls

Forum Archive : Opening Rolls

Rollouts of openings

From:   Tom Keith
Date:   16 January 2006
Subject:   Rollouts of all opening moves

I have now posted 2-ply rollouts of all the opening moves. You can find
them here:

All reasonable plays are rolled out 46,656 times using Gnu Backgammon at
2-ply play, its highest (practical) level.

Neil Kazaross  writes:

Since your work is cubeless, I'll take my stab at cubeful for a few
plays based on my "guesstimates" of cubeful adjustments and noting that
the play that wins the most games almost always gains equity cubefully.
These comments are for cubeful money play or very early in a long match
unless otherwise specified

2-1: even clearer to slot with cube in play.

3-2: almostly certainly correct to split with cube in play due to 0.40%
more wins.

4-1: a bit closer to correct with cube in play, but still only best at
GG (clear) and DMP close (we rolled these out at GoL).

4-3: 20/10 seems never correct and I never make that move anymore. The
minor split would be close cubeful, but I have built for several years
and will continue to do so. A long GS rollout here (by me) showed that
at GS the minor split is best. DMP rollouts here (by several) tend to
very slightly favor 2 up.

5-2: it is now quite clear that the split is best except at GG.

6-2: slotting won my GG rollout at GoL.

5-4: split is real clear except at GG. I don't think the 5-4 or 6-3 run
is best at GS. (I think someone did 6-3 run at GS here and split won by
a bit.)

6-4: making the two point or slotting are extremely close cubeful (see
PG's data) 6-4 run vs split need to be rolled out both at DMP and GS.

6-5: even at GG the split isn't best. I run vs anyone. Weaker players
make plenty of errors vs 1 checker back when they trail in the race and
must fear the G.

Chris Yep  writes:

It's interesting that you come up with a gammon rate of 27.62% using GNU
2-ply rollouts. Over the years, the best-guess gammon rate has been
increasing as bots have gotten stronger and stronger. By any chance do
you know (or have an estimate) what the gammon rate is using GNU 0-ply
rollouts? I wonder what the true gammon rate is (with perfect play).
I'll guess 29%.

Tom Keith  writes:

Gammon rate using GNU 0-ply rollouts is 26.59%.
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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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