Forum Archive : Propositions

Opening 11 vs. Owning the cube

From:   Bob Ebbeler
Date:   20 August 1999
Subject:   Re: Double on double 1 ?
Google:   NCov3.441$dO3.8557@news4.mia

> If you throw a double one and take the 5 and the 7 point you are
> (1) Blocking your opponent (2) 2 points away from setting a prime
> (3) giving yourself good time to create a hard anchor (4) giving
> youself a good block to help move down pieces from the 13 point.
> You are at a clear advantage in the game.
> It is my *tactical* decision to double. Please advise me if this is
> the ramblings of a misguided idiot.

One of my earliest, expensive lessons was over the issue you raised. I
wound up playing a proposition with another player wherein I started with
1-1 and he had the doubling cube on his side at 2. This was, and probably
still is, a time honored proposition and I will, hopefully, save you the
expense of learning the lesson I learned.

The guy who has the cube CRUSHES the guy who starts with 1-1.


Paul Tanenbaum  writes:

<sigh> Bob, a backgammon hustler you aren't.  The idea is to recoup
the cost of your lesson at somebody else's expense.

    What was the equity for the cube-holder (assume at the 2-level)?

    Presumably you played it {6/5(2), 8/7(2)}.  However, I don't like
giving the indirect shot at the blot, so I would try {6/5(3), 24/23}.
Has this alternative been rolled out?   Probably not enough to make a
difference in the prop, though.

Daniel Murphy  writes:

This proposition illustrates the value of cube possession.  Early
double aces is usually a fine number, and played 8/7(2) 6/5(2) on the
very first roll of the game is enough to make you a 55-60% favorite
straight off, but you forfeit your entire advantage if you have to
give your opponent the cube before you move!

I read "CRUSHES" to mean "solid favorite," and like Bob's hustler, I'd
also happily let my opponent start with 11 in exchange for cube

A too-quick JF level 5 rollout (1296 rollouts, .550 settlement,
0.029-0.038 standard deviation) makes the player with 11 a 56%
favorite cubeless, but a 46% underdog if his opponent has the cube. In
this rollout, JF still thinks the player with 11 has an 0.072 equity
edge, but I think the rollout gives way too little credit to
opponent's redoubling and gammon chances.

I undaringly predict that 6/5(2) 8/7(2) "crushes" all alternatives in
rollouts, and that 6/5(2) 24/22 does better than 6/5(3) 24/23.

(In a real game, don't be afraid to split to the 22 point with 11 if
6/5(2) 8/7(2) would leave a _direct_ shot at the blot on the 8 point.
And, in a real game, be very wary of moving your last spare checker
from the 6 point to the 5 point. More often than not, that one little
move will come back to haunt you before the game is through.)
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Choose roll vs. double roll  (Larry Deckel, Jan 1997) 
Choose roll vs. double-roll  (Rafy Marootians+, Mar 1994) 
Eight checkers vs. fifteen  (Raccoon, Feb 2006) 
Fifteen on the bar  (Pete+, Nov 2002) 
Monte Carlo 1998  (Daniel Murphy, Feb 2006)  [GammOnLine forum]
No ones  (Murat Kalinyaprak, Oct 2002) 
Opening 11 vs. Owning the cube  (Bob Ebbeler+, Aug 1999) 
Tino Road Position  (Arthur+, Apr 2005) 
Up in the air  (Daniel Murphy, Feb 2006)  [GammOnLine forum]

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