Opening 6-4
Dave Boggitt
games. I seem to be having some success with it, but I
would like the views of some players with rather more insight
than myself. i.e. the rest of fibs
I've been playing 1-5 12-18.
The (somewhat distorted) logic is that if i get hit on either
point, then i've got a good chance of coming back on quickly
and winning either the 5- or 18-point. Both of these give useful
footholds in the game.
Thanks,
Dave.
fibs = DavieChoad
David Montgomery
[ 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
were).
David Montgomery
monty on FIBS
Anthony R Wuersch
David Montgomery <mo...@cs.umd.edu> wrote:
>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
>were).
Didn't Neil also write on the 6-3 play after 3-1 in Leading Edge?
My recall is that he thoroughly agrees with Roy et.al..
I'm surprised that Neil would play 24/15 so that he would have been
doubled and then would pass.
But let's say he did. He might pass because it's no fun if he took
--- it's not hard for the ahead team to play.
As a top player, Neil might prefer playing more games so his skill
edge has an better chance to come through.
--
Toni Wuersch
a...@world.std.com {uunet,bu.edu,bloom-beacon}!world!arw
David Montgomery
>In article <3r7gg2$1...@twix.cs.umd.edu>,
>David Montgomery <mo...@cs.umd.edu> wrote:
>>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
>>to an opening point maker as well ].
>Didn't Neil also write on the 6-3 play after 3-1 in Leading Edge?
I don't think so.
>I'm surprised that Neil would play 24/15 so that he would have been
>doubled and then would pass.
>
>Toni Wuersch
I went home and looked it up. From the December 1990 Leading Edge
Backgammon (Roy Friedman is presumably the author, since it doesn't say):
The Kazaross Pass. Ascutney Mt., Vermont, August 1990.
Walter Trice and I were playing a Doubles match against
Neil Kazaross and Trish Heglund. We needed four points
to win the match and they needed two points. We opened
with 31 and they rolled 63, running with 24/15. We
doubled and, after some hesitation, they passed. Later,
I talked with Neil about their pass after playing 24/15.
Neil was fairly confident that the pass was correct but
he had never thought about it before because no on had
ever doubled him in that situation!
Then Roy goes on to conclude that the pass was correct, but that
after the correct play, 24/18 13/9, the position was a take.
But that was almost five years ago. People change their minds.
USRobots
Greetings,
Dave Boggitt asked about playing an opening 6-4 as 24/20, 13/7, which
leads to the following position:
24 23 22 21 20 19 18 17 16 15 14 13
-----------------------------------------------------
| X X O | | O X |
| O | | O X |
| O | | O X |
| O | | X |
| O | | |
| |BAR| |
| X | | O |
| X | | O |
| X | | X O |
| O X | | X O |
| O X | | X X O |
|_______________________|___|_______________________|
1 2 3 4 5 6 7 8 9 10 11 12
This move seems too aggressive to work well against a top player, or even
an intermediate like myself. As O in such a position, after ANY roll, I
can and would hit a blot (with 2-5 and 4-5, I would hit on the 24-pt and
split my runners). I also have 9 or 10 rolls (1-4, 1-6, 3-3, 3-4, 3-6,
and maybe 6-6) that double-hit. Encouraging such contact with an
otherwise useful opening roll does not seem right. Furthermore, an
exchange of hits on the 7-pt is bad for X, who will end up with 4 or 5 men
back, while O will only have 2 back. Such a situation is a big
disadvantage against a skillful player. The more respected splitting play
24/18, 13/9 makes sure almost every blot-hitting contest will take place
on the opponent's side of the board.
On the positive side, this type of opening move can work well against a
beginner. If O is at all timid about hitting in this position, X often
will build a sizeable advantage quickly. Also, X won't be worried about
having extra men back against a beginner. The extra equity against weaker
players might make this move a good practical option. I, for one, would
not play it against strong opponents.
Thanks,
USRobots
usro...@aol.com
Igor Sheyn
point is 20% ( slightly less actually, about 18% using 59% equity for
-2:-3 ) and gammon rate for trailer is 1.0. But I think that
number is exhagurated(sp?) because of incompetency of EXBG rollouts.
Besides, against imperfect opponent u should always take because of
potential equity gain. But it's an interesting match-score situations,
and I will roll it out on JF. What would be the suggested horizon
level? Or rolling it out all the way reflects the equity better
because of cube immobility?
Igor