Opening Rolls

Forum Archive : Opening Rolls

Opening 43: Which split is better?

From:   Michael J. Zehr
Date:   17 March 1996
Subject:   43 split opener
Google:   4ii80k$2tq@senator-bedfellow.MIT.EDU

A few issues ago in Inside Backgammon there was an annotated match with
an opening 43.  One of the commentators said that 24-21 13-9 wasn't even
worth talking about.  I'm interested in starting a discussion about this
option.  When I split (I usually do because of the style of game it
leads to) I split with the 3 and bring the 4 down.  Here's my reasoning:

On the plus side:
Your opponent's perfectas aren't quite as good.  11 and 33 are stronger
when you split to the 20pt than 22 and 44 when you split to the 21pt.
21 Also plays better for your opponent when you're on the 20 than the 21
because they can bring down a builder to cover it.

Your builders are in better position.  Since the 6 and 8 points are
already 2 apart, having a checker on the 10 doesn't give you that many
more rolls to make points.  24 and 13 are duplicated, for example.  If
you're not hit, you get a lot more chances to make points.

On the neutral side:
With either play, 8's and 9's hit on one side of the board or the other.

On the minus side:
If you make an advanced anchor, it's on the 21, not the 20.

Am I misjudging the weight of the minus side?  Misjudging the importance
of spreading out the builders (since often you're hit so you don't get
to use the better distribution anyway)?

-michael j zehr

Julian Hayward  writes:

No, I fully agree with you. Another factor is that many opponents who
would routinely attack on their 5 point wouldn't even consider attacking
on 4 - so you have more chance of getting the anchor.

Peter Bell  writes:

Isn't this all just "splitting" hairs?  I'm not sure if the quote from the
Inside BG is out of context, but it seems absurd to say 24/21 13/9 is not
even worth talking about at an even match score.  The two splitting moves
seem to have nearly identical equity.  I've played many games with both
and noticed no difference, which proves very little, granted.  More
importantly, Kit's rollouts of the opening rolls with JF a while back
showed no significant difference between the two rolls, which proves
more.  Also, most of my opponents >1700 seem to play 24/21 13/9 these

However, the volatility of 24/20 13/10 seems higher: since the battle is
for the 5-point, more hinges on the outcome.  I can see striving for
higher volatility when way behind in the match or when gammons help you
more than your opponent: was this the point of the commentator?  Of
course, in those situations, I'd bring down two builders anyway.

Peter Bell (USRobots)

Lasse H. Madsen  writes:

The main reason why I prefer the 21-point split to the 20-point split,
however, is that the replies are more difficult to play. Consider, for
example, the reply of 2-1. If the split is made to the 20-point it is
very clear to hit loose, but if the blot is on the 21-point, hitting
loose is not quite so clear-cut. The same argument goes for the 5-2
response. Thus, the 21-point split tend to generate more misplays.

Furthermore,  if the opponent eventually wins the fight for his
4-point, you still have the chance of anchoring on the 20-point - a
much better situation than the corrosponding sequences where you
anchor on the 21-point after losing the battle for the 20-point.

> On the neutral side:
> With either play, 8's and 9's hit on one side of the board or the other.
> On the minus side:
> If you make an advanced anchor, it's on the 21, not the 20.

Right, but in some variations the 21-point actually works *better*
than the 20-point. This happens when your opponent quickly claim a big
lead in the race, but fails to make his 5-point. The resulting holding
game may well be stronger for you if you are anchored on the 21-
rather than the 20-point, because the gap on the 5-point can generate
extra shots.

I think you are right in prefering 24/21 13/9 over 24/20 13/10 on an
opening 4-3.  While this may not be the technically correct play, I think
practical concerns makes it very effective.

Lasse H. Madsen
Did you find the information in this article useful?          

Do you have any comments you'd like to add?     


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) 

[GammOnLine forum]  From GammOnLine       [Long message]  Long message       [Recommended reading]  Recommended reading       [Recent addition]  Recent addition

  Book Suggestions
Computer Dice
Cube Handling
Cube Handling in Races
Extreme Gammon
Fun and frustration
GNU Backgammon
Luck versus Skill
Magazines & E-zines
Match Archives
Match Equities
Match Play
Match Play at 2-away/2-away
Opening Rolls
Pip Counting
Play Sites
Probability and Statistics
Source Code
Strategy--Bearing Off
Strategy--Checker play


Return to:  Backgammon Galore : Forum Archive Main Page