Opening Rolls
Kit Woolsey
Reprinted from rec.games.backgammon
Subject: Re: What are the best ways to play the opening rolls?
From:
kwoolsey@netcom.com (Kit Woolsey)
Date: Sun, 19 Mar 1995 05:19:43 GMT
Message-ID: kwoolseyD5o9Gv.83F@netcom.com
Andrew Paik (paik@crl.com) wrote:
"Hi Everyone. On the surface, this seems like a really easy question. What
is currently believed to be the best way to play the different opening rolls? I
thought I knew this stuff, but when I read the ACM/TD-Gammon article, they said
that TD-Gammon had `changed the way experts play'. For instance, they said that
slotting the five was now generally considered inferior to splitting the back
men to use the 1 for some of the opening rolls. This was news to me, but then
I'm not one of the experts. Since there are experts here, I thought I would
ask..."
It is quite true that rollout results from three backgammon playing computer
programs (Expert Backgammon, TD-Gammon, and Jellyfish) have given us new
insights into opening rolls and other phases of the game. Before taking any of
these as gospel, there are several things to keep in mind:
- The strengths and weakness of the programs. For example, a program which
is weak in backgame play might downgrade early slotting plays in its rollouts
since these plays will probably lead to backgames more often when the slotted
blots are hit.
- The rollouts do not take into account access to the cube, which might make
a difference.
- There can be quite a bit of variance in the rollouts due to luck, even
with large sample sizes.
- The rollouts do not take into account individual personalities of players
playing. A player may well do better with an "inferior" opening play if it
suits his personal style.
- If playing a match, the match score may affect the value of different
plays.
Now, on the what I believe is an accurate synopsis of the 15 possible opening
rolls:
- 2-1: The slotting play 13/11, 6/5 and the splitting play 24/23,
13/11, the two most common plays, seem to be about equal. Nothing else is a
serious contender.
- 3-1: 8/5, 6/5 is obviously the only play.
- 4-1: The splitting play 24/23, 13/9 has come out clearly superior
to the slotting play 13/9, 6/5. Probably the reason is that with the builder
on the 9 point there are so many good pointing numbers next turn anyway that
you don't need the 5 point slotted.
- 5-1: The splitting play 24/23, 13/8 has come out a bit better than
the slotting play 13/8, 6/5. A third less common alternative, 24/18, came out
clearly worse.
- 6-1: The obvious 13/7, 8/7 is correct. Magriel's experiment of
13/7, 6/5 is awful.
- 3-2: The splitting play 24/21, 13/11 came out a bit better than
building with 13/10, 13/11.
- 4-2: 8/4, 6/4 of course.
- 5-2: The normal play for years has been 13/11, 13/8. However the
newer splitting play, 24/22, 13/8, (shunned because of the crushing 5-5
threat) has come out a bit better. The slotting play of 13/8, 6/4 (which used
to be my choice) did not survive the rollouts -- it was clearly inferior.
- 6-2: The splitting play of 24/18, 13/11 comes out fairly clearly
superior. Running with 24/16 is 2nd, but the run isn't far enough. Slotting
with 13/5 (a common choice several years ago) was definitely in third place.
- 4-3: The building play of 13/10, 13/9 and the common splitting play
of 24/20, 13/10 were just about tied. The alternative split of 24/21, 13/9 was
only a little behind.
- 5-3: The simple 8/3, 6/3 is clearly best. The once common 13/10,
13/8 has been found vastly inferior.
- 6-3: The splitting 24/18, 13/10 comes out best, but the running
play of 24/15 is not too far behind.
- 5-4: Splitting with 24/20, 13/8 and building with 13/9, 13/8 come
out quite close (that builder on the 9 point is powerful), with the split
generally a tiny bit better. 24/15 is weaker still.
- 6-4: Both running with 24/14 and splitting with 24/18, 13/9 are
about equal. However the once laughed at 8/2, 6/2 has reared its head as a
serious contender and comes out about equal with the other choices -- nice
play to try if you get familiar with it, since your opponent probably won't
be.
- 6-5: The simple 24/13 is clearly better than any other
possibilities.
Kit
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