Puzzles

Forum Archive : Puzzles

 Shortest game

 From: Stephen Turner Address: sret1@cam.ac.uk Date: 23 January 1996 Subject: Re: shortest/longest games Forum: rec.games.backgammon Google: 3104D841.4328@cam.ac.uk

```Marc Gray wrote:
> In the Guinness Book of World Records there appears the following
> re: the shortest backgammon game possible: "Alan Malcolm Beckerson
> (b. 21 Feb. 1938) devised a game of just 16 throws in 1982."
> Does anyone know what the 16 shakes and their corresponding moves
> are?

That's shortest game cubeless, of course. But I claim it's impossible.
Each player starts with 34 tables to change, which can't be done in
fewer than 9 throws. So the shortest game most be at least 17 moves.
I'll try and remember to ask Alan at the next BIBA tournament.

No, I don't know what the moves were, but it's quite easy to devise
some. What's not so easy is to devise a game where each player plays
the correct moves all the time and it ends in 17 moves. Here is an
attempt at such a game. I believe all the moves to be correct except
X's 3rd move. (Though that's not so wrong that it's implausible that
anyone might play it). Can anyone devise one were the indisputably
right move is played all the time?

Score is 0-0 in a 1 point match.
Opponent is X - Turner is O
O: (6 3) 24-18 13-10
X: (3 5) 17-22 19-22
O: (6 6) 24-18 13-7 13-7 10-4
X: (5 5) 12-17 12-17 12-17 17-22
O: (6 6) 13-7 13-7 8-2 8-2
X: (5 5) 12-17 17-22 19-24 19-24
O: (6 6) 18-12 18-12 12-6 8-2
X: (2 3) bar-3 1-3
O: (6 6) 7-1 7-1 7-1 7-1
X: (3 3) bar-3 8-5 8-5 8-5
O: (6 6) 12-6 6-off 6-off 6-off
X: (2 3) 3-5 5-8
O: (6 6) 6-off 6-off 6-off 6-off
X: (6 5) 8-13 13-19
O: (5 5) 4-off 2-off 2-off 2-off
X: (4 3) 3-7 3-6
O: (1 1) 1-off 1-off 1-off 1-off

--
Stephen R. E. Turner
Stochastic Networks Group, Statistical Laboratory, University of
Cambridge
e-mail: sret1@cam.ac.uk
WWW: http://www.statslab.cam.ac.uk/~sret1/home.html
```

 Kit Woolsey  writes: ```Ok, Steve, I think I've found one (wasn't easy) which involves correct play. All the moves were deemed correct by jellyfish level 5 (and only the opening 4-3 play was close), so how bad can that be. X: 4-3 13/10, 13/9 O: 5-5 13/3(2) X: 5-5 13/3, 10/5, 8/3 O: 5-5 13/3, 13/8(2) X: 6-6 24/18(2), 13/7(2) O: 3-3 24/21(2), 8/5(2) X: 6-6 18/12, 18/6, 9/3 O: 6-6 21/9(2) After that, X just rolls 6-6 each roll. I think this meets the stipulated conditions. Kit ```

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