Opening Rolls

Forum Archive : Opening Rolls

Opening 65: Computer rankings

From:   Chuck Bower
Date:   3 January 1997
Subject:   Re: need jelly analysis 6/5 opener
Google:   5ajd44$

> Hi Folks. Was wondering if anyone could give jellyfish analysis
> on the 6/5 opener..... I know that it [24/13] is the *best* move
> but would like to see the comparison between running vs. bringing
> a builder down with the 5 and pointing on opponents bar point
> with 6. Thanks in advance.

Stuart writes:
> For an opening 65 at money play I get the following L7 2-ply
> estimates:
> 24/13        +0.067
> 24/18 13/8   +0.019
> 13/7 13/8    -0.039

     I agree with Stuart.  Furthermore, here is JF level-6 rollouts
(432 trials each) say:

                 money           money
play           cubeless        cubeless
                equity        total wins

24/13         +0.077(0.013)  +53.9(0.5)%
24/18, 13/8   +0.031(0.012)  +51.2(0.5)%

(numbers in parentheses are standard deviations)

     Now for some commentary.  Back in the 70's it became popular
to belittle the 65 opener played 24/13 (known as "lover's leap").
The macho players preferred slotting plays (for example 21 played
13/11, 6/5).  The ultimate derision came in "Backgammon for Blood"
whose author (Bruce Becker) remained incognito, even after being
publically challenged to come forth by Lewis Deyong.

     Computer players (EXBG, TDG, JF, Loner) have since unanimously(?)
agreed that not only is 24/13 the correct play, but 65 is by far one
of the best opening rolls!!  Here is how JF level-6 rollouts (432
trials each) ranks the opening rolls:

                       money                money
roll play            cubeless     rank    cubeless       rank
                      equity             total wins

31  8/5,6/5        +0.162(0.014)   1    +55.0(0.5)%       1
42  8/4,6/4        +0.087(0.014)   2    +52.5(0.5)%       4
61  13/7,8/7       +0.085(0.014)   3    +52.8(0.5)%       3
65  24/13          +0.077(0.013)   4    +53.9(0.5)%       2
53  8/3,6/3        +0.060(0.014)   5    +52.3(0.5)%       5

caution, though:  JF is playing for "money" which means gammons
count twice as much as simple wins, etc.  If gammons don't count
--like at double match point--these results will likely be a bit
different.)  The reason 65 is worse in total equity is because
it doesn't WIN as many gammons as the building plays.  As far
as gammon LOSSES go, it is about the same as the building plays
(except 31, which is best all around).

      c_ray on FIBS

P.S.  Do you think Bruce Becker reads the newsgroup??
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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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