Opening Rolls

 Opening 1's: Split or slot?

 From: Douglas Zare Address: zare@math.columbia.edu Date: 3 December 2003 Subject: Re: 2-1 as an opening move. Forum: rec.games.backgammon Google: 3FCD3C30.BD50E802@math.columbia.edu

```> This has been discussed on Gammonline recently, and it seems like the
> strongest players have pretty much come to a consensus that slotting is
> slightly better at even match scores/money for 2-1, and slightly
> inferior for 4-1, 5-1.

I don't think there is a consensus. One of the recent threads there
slotting is more right with 2-1 at 3-away 3-away than for money,
perhaps by enough to call splitting an error at 3-away 3-away.
For money, though, I think people would be surprised if one of
the alternatives were clearly better than the other.

> The reason is the ideal placement of the builder
> on the 11, 6 points away from the slotted 5, vs. on the 9 which is such
> a powerful builder that there is a lot of duplication, or the 8, which
> leaves you only a bit better than 50/50 to cover if not hit.

After slotting with 5-1, in addition to 1s and 3s (20 numbers)
you can also cover with 8s (4 additional rolls, though covering
with 2-2 is inefficient), 5-2 makes the 3 point, and sometimes
5-4 makes the ace point. That's up to 28 numbers making use of
the slot to create a new inner board point. Other numbers
(6-4, 6-6, 5-5, 5-6, and 4-2) leave the point slotted, and if it was
reasonable on the first roll, it usually isn't so bad on the second
roll.

Slotting with 5-1 gets hit on all 4s except for 1-1, which is better
played elsewhere, but 3-1 and 4-2 are duplicated. This
duplication is more important than most players think. I still
tend to split with 5-1, though.

> Slotting is a gammon-hunting play on 4-1 or 5-1, best only when behind,
> or gammons are more valuable than usual.  Slotting at 2-1 stands quite
> well on it's own, except at scores where *losing* the gammon is more
> problematic than usual.

I think the slot with 4-1 is fine at DMP.

I don't think slotting wins as many gammons as people expect,
since getting a third checker sent back makes blitzing extremely
difficult.

It is clearly wrong to slot if your opponent has a free drop,
at post-Crawford 2-away or 4-away, for example. Then
slotting means that your opponent will have a huge take if
the slot is hit, and probably a big pass otherwise, rather than
a close decision most of the time after a split.

Although people argue that slotting makes the game more
complicated, I think this argument is far stronger in other
situations, such as for making the deuce point on an opening
6-4. People rarely make significant errors on the response
to a slot, but _most_ players misplay several responses to
8/2 6/2. Although Snowie 4 dislikes making the deuce point
on the level of evaluations, its rollouts say the play is fine,
and that Snowie consistently undervalues the blitz in the
opening.

Douglas Zare
```

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)
Magriel's Chapter 5  (Hayden Alfano+, May 2006)
Mloner vs Jellyfish  (Kit Woolsey, Dec 1995)
Nactating a whole game  (Nack Ballard+, Jan 2011)
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)
Opening 21: Split or slot?  (Dick Adams+, Dec 2003)
Opening 32: Rollout  (Stick, Feb 2006)
Opening 43: In GOL online match  (Raccoon+, Feb 2004)
Opening 43: Pros and cons  (Stick+, Jan 2006)
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)
Opening 52: Merits of splitting  (Peter Bell, Apr 1995)
Opening 53: Magriel's recommendation  (George Parker+, July 1997)
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)
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)
Rollouts: Snowie 4.1  (Rene Cerutti, Apr 2004)
Slotting the four point  (Joe Loria+, Oct 1999)
Snowie's openers and replies  (rcerutti, Feb 1999)
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)