Home
Home Kurzvorstellung Backgammon Links Site Map Kontakt/Impressum


Where Magriel erred ...


Cover
Magriel's Backgammon published in 1976 is still considered the "bible of backgammon". But our insight about the correct play has changed since good backgammon software is available (Jelly Fish ™ made the breakthrough in 1994). So some of Magriel's recommendations did not survive the bots and are not correct from today's view 1) . The following table contains the major errors. It does not claim to be complete, but it should contain the most errors.
I recommend to mark those positions where Magriel probably erred with a pencil in the book before starting to read it. You can study it much more relaxed then.
Where the best move in the column "Best Move" contains a link, you can have a look at the position and the rollout results 2)  by clicking on the link.
The table contains problems from section 2 of his book. Aditionally some of his recommendation about the opening moves are not state of the art any more. For the best opening moves have a look at my article Die Eröffnung (Teil 1) (currently only available in German).

Chapter, Position Magriels Choice Best Move (approx. equity difference)
Ch. 12, Pos.1 7/6 7/4 8/7 8/5 (+0,016)
Ch. 12, Pos. 4 10/8 6/5 9/7 6/5 (+0,032)
Ch. 13, Pos. 20 13/7 13/11 24/22 13/7 (+0,08)
Ch. 13, Pos. 25b 10/4 9/5 20/14 10/6 (+ 0,1)
Ch. 14, Pos. 16 7/1* 8/4 6/4
Ch. 15, Pos. 1 Double - Take No Double (+0,17)
Ch. 16, Pos. 9 8/5* 13/10 (+0,10)
Ch. 17, Pos. 8 13/11 8/7 13/10 (+0,07)
Ch. 18, Pos. 3 23/18 11/6 (+0,10)
Ch. 18, Pos. 5 23/18 6/5 10/5 6/5 (+ 0,086)
Ch. 19, Pos. 2 13/7 8/7 11/5 6/5 (+0,12)
Ch. 20, Pos. 5 8/2 20/14* (+0,15)
Ch. 20, Pos. 7 bar/20 24/20 bar/16* (+0,05)
Ch. 22, Pos. 5 Double - Pass Double - Take (+0,313 for the player getting doubled)
Ch. 24, Pos. 40 9/3 8/6 5/1 (depending on cube: +0,20 or 0,04)
Ch. 24, Pos. 44 18/16 6/5 18/17*/15 (+0,18)
Ch. 24, Pos. 52 18/13/11 18/16* 13/8 (+0,16)
Ch. 25, Pos. 6 9/4 18/13 (+0,10)
Ch. 25, Pos. 7 13/5 13/7 24/22 (+0,11)
Ch. 26, Pos. 14 14/9 13/3 8/3 14/9 13/8 6/1*(2) (+0,12)
Ch. 28, Pos. 2 7/2* 18/13 (+0,15)
Ch. 28, Pos. 4 24/18 7/2* 24/13 (+0,18)
Ch. 28, Pos. 11 20/13 8/3 8/6 (+0,166)
Ch. 28, Pos. 14 10/6 9/7 10/6 4/2 (+0,10)
Ch. 28, Pos. 15 10/9 24/23* (+0,39)
Ch. 28, Pos. 19 8/2* 3/1* 8/2* 8/6 (+0,28)
Ch. 29, Pos. 4 22/20 24/22 (+0,15)
Ch. 29, Pos. 10 13/7 6/4* 24/16 (+0,084)
Ch. 29, Pos. 11 8/3* 6/4 24/22 13/8 (+0,044)
Footnotes
1) Possibly new, stronger software will evaluate some decisions and moves differently in 5, 10 years. Definitively our knowledge about the game will continue to develop and change over the years. So our insight what's right or wrong for Magriel's positions may change.

2) The results are based on rollouts with GNU Backgammon, version 0.14.3 (2005). 1296 rollouts, 0-ply, non-truncated, cubeless.
Last update: 23 July 2008