Opening Rolls

Forum Archive : Opening Rolls

Opening 6's: Slot the bar point?

From:   David Montgomery
Date:   8 June 1995
Subject:   Re: Opening/Reply with 6-{2,3,4} [ was: Opening 6-4 ]
Google:   3r7gg2$

Dave Boggitt writes: [ that he's been trying 24/20 13/7 with an opening
6-4 ]

I call this opening, as well as 24/21 13/7 with 6-3 and
24/22 13/7 with 6-2, the Martinengo split, because its the
way my wife, Laura Martinengo, always plays these rolls.  It's
actually not that bad, and probably at least as good as pulling
2 down from the midpoint.  It might even be the best play if your
opponent mishandles the replies.  In particular, after the
Martinengo split you should be very aggressive about hitting
twice.  For example, although hitting 6/5*/1* after an opening
split with 5-4 is debatable, after 24/20 13/7 it's mandatory.

A few years ago I rolled these plays out with EXBG and they actually
came out ahead of the other plays (all plays were rolled out at
least 10,000 times), but EXBG was not playing the continuations
correctly.  When the followups are played right, I think the
following plays are best: 6-2 24/18 13/11; 6-3 24/18 13/10 or
24/15; 6-4 24/18 13/9 or 24/14 or 8/2 6/2.


I think the Martinengo split may be correct as the reply to
some openings, however.  For example, after a 2-1 opening played
13/11 6/5, the best 6-2 play may be 24/22 13/7.  The 6's needed
to hit are duplicated, and the blots in the opponent's board
are relatively immune to attack because of the slot on the
5 point.

A few years ago, Roy Friedman wrote an article in Leading Edge
Backgammon analyzing the following sequence:

Match Score -2:-4
X: 3-1 8/5 6/5
O: 6-3 24/15
X: double
O: pass

Based on rollouts that Roy and Paul Weaver did, the conclusion
was that the pass was correct, and that the best play with
6-3 here was 24/18 13/10.  Following this, many players
changed the way they played a 6-{2,3,4} as a response to
an opening point maker (3-1, 4-2, 5-3 [6-4?]) from running
to splitting.  The rollouts had splitting losing 19% gammons
afer a double and a take, while the running play lost a whopping
27% gammons.

I think that the gammon figure obtained for running is almost
certainly more than the "true" number.  In fact, I think that
in general running is the *less* gammonish play.  Here is how
I would now handle a reply of 6-{2,3,4} at -2:-4 and -4:-2,
following an opening 3-1:

     leading  -2:-4     trailing -4:-2
6-2    24/18 13/11        24/18 13/11
6-3    24/15              24/18 13/10
6-4    24/14              8/2 6/2

Also, I think that O has a take at -2:-4 after X: 3-1 8/5 6/5
O: 6-3 24/15.  But I would like to hear what others think about
this situation.  Perhaps one of the Boston area players could
ask Roy what he currently thinks.  I would also be especially
curious what Neil Kazaross thinks, since he was one of the
two O players who passed (it was a doubles tournament -- sorry,
I don't recall who Neil's partner was nor who their opponents

David Montgomery
monty on FIBS
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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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