Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10 6/7/83; site hao.UUCP
Path: utzoo!linus!philabs!seismo!hao!woods
From: woods@hao.UUCP (Greg Woods)
Newsgroups: net.games
Subject: Re: bearing off
Message-ID: <669@hao.UUCP>
Date: Mon, 24-Oct-83 00:52:26 EDT
Article-I.D.: hao.669
Posted: Mon Oct 24 00:52:26 1983
Date-Received: Wed, 19-Oct-83 21:15:33 EDT
References: <541@sunybcs.UUCP>
Organization: High Altitude Obs./NCAR, Boulder CO
Lines: 40


>     In backgammon even an innocent-looking position may
>     contain a pitfall.  Ask yourself how you would play
>     6-4 in this position--then ask a computer program
>     the same question!
>     
>          | O           |BAR|
>          | O   O   O O |BAR|
>          +------------------
>          1   3   5 6

-----------------------------------------------------------------------------

  Obviously, the first reaction would be to say you have to pull off the six
and move the piece on 5 to 1. However, this leaves

	O
      | O           |BAR|
      | O   O       |BAR|
      +------------------
	1   3   5 6

and if you now roll a 2-1 (only a 1/18 chance, but still) it will take you 3
turns to get all your pieces off. 
However, it is legal to move the piece on six to two, and then use the 6-roll
to bear off the piece from 5. This leaves:

      | O           |BAR|
      | O O O       |BAR|
      +------------------
	1   3   5 6

now you would have to roll 2-1 2 consecutive times, a 1/324 chance, not to get
all your pieces off in 2 turns. Therefore, the latter is the superior move. I'll
bet that's what the program did! 

			GREG
-- 
{ucbvax!hplabs | allegra!nbires | decvax!brl-bmd | harpo!seismo | ihnp4!kpno}
       		        !hao!woods