Backgammon Programming

Programming

BKG beats world champion

From:   Marty Storer
Address:   martys@juliet.ll.mit.edu
Date:   10 September 1991
Subject:   Re: Computer Backgammon
Forum:   rec.games.backgammon
Google:   MARTYS.91Sep10130048@escalus.juliet.ll.mit.edu

> Several years ago, there was a backgammon program that defeated the world > champion in a exhibition match. This was described in Scientific > American and I have been told that the program was briefly sold packaged > on a PC for about $4000 around 1982. Of course, the general > marketability of a $4000 dedicated backgammon computer being what it is, > the enterprise quickly failed. (One could also argue that $4000 is better > spent playing against and learning from experts, but that's another > story). > > At any rate, the computer won, but an analysis of the games revealed that > 8-9 mistakes were actually made by the program, and were glossed over by > the roll of the die. We all know this from club or tournament play; > there is no substitute for rolling well ;-) The difference between an > expert and a experience club player is perhaps 3% (feel free to argue > this one!)...well, to me that translates into 48.5% of the time the > lesser player will win. That's why experts like to play rounds of 11 or > 17 points and are very cautious (i.e. judicious) with the cube. The more > games, the greater their advantage over the lesser player. I believe the > exhibition match was to 9. The match took place in '79, I believe, and I think it was a 7-point match. A program developed by Hans Berliner of CMU defeated the winner of the annual Monte Carlo tournament, Luigi Villa. (There's no "World Champion" in backgammon in the same sense as there is at chess; the winner of the Monte Carlo tournament is labeled the World Champion for some reason, despite the lack of central organization and all the other trappings of the World Chess Championship that backgammon lacks.) I remember seeing the complete match score in some backgammon publication or other around '79-'80; the machine didn't play as well as Villa did, but played pretty well nevertheless. The statement that there are programs that play better than humans was probably made by someone who heard something about the computer-vs.-Villa match. It's false, anyway--the standard of play has improved considerably since then, and there has been hardly any work on computer backgammon to extend Berliner's very good work. A program called Expert Backgammon, recently on the market and available through various backgammon organizations, seems to play a halfway-decent-but-not-that-great game. I think Berliner made the "8-9 mistakes" claim (or a similar one) in his subsequent Scientific American article on his program, his methodology, and the match. I'd bet the machine made more mistakes than that; I don't think anyone but Berliner did the analysis you mention--at least, he didn't say otherwise in his article. I don't think Berliner's a recognized expert; I know that he claimed the machine made a brilliant move with a roll of 22 in the last game of the match, when in fact the move was a blunder. (The machine won a hopeless race by throwing multiple sets of doubles; its 22 move facilitated racing. This caused some on-site expert commentators to label the move a good one, and probably influenced Berliner's thinking about it. I'll dig up the article and post my analysis of the position, if anyone wants me to.) Anyway, Berliner's article (June 1980 Scientific American, I think) is well worth reading, especially for people wishing to develop strong backgammon programs. Play well, Marty

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