David Levy

All about chess and computers

Chess and Computers.- 1 Chess Machines.- 2 How Computers Play Chess.- 3 The Early History of Computer Chess.- 4 The Modern Era of Computer Chess.- 5 Computer Chess Tournaments.- 6 Current Research and Future Prospects.- 7 Stop Press.- More Chess and Computers.- 1 The Levy Bet-End of an Era.- 2 The State of the Art.- 3 Blitz Play.- 4 Computer Chess Tournaments.- 5 Microcomputers and Chess.- 6 Computer Chess Miscellany.- 7 Postscript: 1978-80 and BELLE The World Champion.- Appendix A - An Unsolved Problem.- Appendix B - Games from 1977 touurnaments.

Current Research and Future Prospects

The games played at the first World Computer Championship serve as an accurate guide as to the current state of the art. In my opinion, the standard of play exhibited in Stockholm was not outstandingly better than that of Bernstein’s program (1957) or even of Turing’s hand simulation. It is true that the programs of today do not make gross tactical blunders so often as those of twenty years ago, but in terms of strategical concepts the advances that have been made during the past two decades are negligible.

Postscript: 1978 – 80 and BELLE The World Champion

Since the original manuscript for this book was completed, four major computer chess tournaments have been held: three ACM tournaments—Washington in 1978, Detroit in 1979, and Nashville in 1980—and the Third World Computer Chess Championship in Linz, Austria. The story of these events has been the remarkable success of Ken Thompson’s and Joe Condon’s BELLE. BELLE won the 1978 ACM tournament, became world champion at Linz on September 28, 1980, and won the 1980 ACM tournament one month later. A second place finish in the 1979 ACM tournament marred an otherwise perfect record.

Microcomputers and Chess

Researchers who first described how computers might be programmed to play chess were talking about machines costing millions of dollars. These machines occupied entire laboratories, ran on vacuum tubes or mechanical relays, required large amounts of electricity, generated vast amounts of heat, and failed at intervals measured in minutes or hours. They executed approximately 10,000 instructions per second, compared with 10,000,000 or more on some big fast machines currently available. They had to be programmed in machine language, a language that must have driven a certain number of programmers in the 1950’s into a permanent state of insanity. Memory space was measured in bits rather than in kilowords as it is now, thereby placing severe restrictions on the size of programs. Finding mistakes in programs was a tremendous task. Programmers complained that their programs failed because of hardware problems while the technicians called in to find the mysterious bugs countered that the problems were with the programs. The two were always seen working together and blaming each other for their own woes.

The Early History of Computer Chess

On March 9th 1949 Claude E. Shannon, a research worker at Bell Telephone Laboratories, Murray Hill, New Jersey, presented a paper at a New York convention. His paper was called Programming a Computer for Playing Chess and its enormous significance lies not in the fact that it was the first paper to be published on the subject but that many of Shannon’s original ideas can still be seen in today’s programs. Shannon did not claim that computer chess itself was of any practical importance but he did realize that a satisfactory solution to the problem might result in progress being made in other areas of automatic problem solving. In particular, he listed the possibility of building machines (i.e. writing programs) that could design electronic circuits, handle complex telephone switching problems, translate from one language to another, make strategic decisions in simplified military operations, orchestrate a melody or handle problems of logical deduction.

The Levy Bet — End of an Era

In August 1968—I attended a conference on Artificial Intelligence at Edinburgh University’s Department of Machine Intelligence and Perception. At a cocktail party one evening during the conference, I happened to be playing a friendly game of chess with John McCarthy, a professor of Artificial Intelligence at Stanford University and one of the world’s leading authorities in his field. I won the game, and he remarked that although he was not strong enough for me, he thought that within ten years there would be a computer program that could beat me. You can imagine my reaction. I was the reigning Scottish Chess Champion at the time, and here was this inexpert player telling me that in only a few years I would succumb to a computer program! I said something roughly equivalent to (but more polite than) “put your money where your mouth is,” and I offered to bet Professor McCarthy £500 (then worth

Computer Chess Tournaments

1,250) that he was wrong. Our host for the evening, Professor Donald Michie, who was sitting on the floor only a couple of feet away, joined in our debate and agreed to take half of the bet, McCarthy taking the other half.

The Modern Era of Computer Chess

During the course of the preceding pages I have often referred to events in which the only participants were computer programs. At the time of writing seven such events have been held: Five ACM tournaments, one tournament in Canada in 1974 and one World Championship tournament (also in 1974). The ACM tournaments show every sign of increasing in popularity, with more and more programming groups expressing an interest every year. Although the number of programs that compete at these tournaments is usually limited to twelve, there are often as many as twenty that apply to take part. When selection is necessary programs are chosen or rejected largely on the basis of sample games that are sent in by the programmers.

Computer Chess Miscellany

Beginning in mid-November 1966, a chess program was developed on a PDP-6 computer at the Artificial Intelligence Laboratory at M.I.T. The program was written primarily by Richard Greenblatt, then an undergraduate student, with the assistance of Donald E. Eastlake III. The program was written quickly—by February 1967 it was ready to play in a local tournament where it lost four games and drew one to achieve a rating of 1243 on the United States Chess Federation scale. In March 1967 it played in another tournament, winning one game and losing four. Its performance rating for that event was 1360 and its overall rating went up to 1330. One month later it scored two wins and two losses for a performance rating of 1640. The program was named Mac Hack VI and it was made an honorary member of both the U.S.C.F. and the Massachusets Chess Association.

How Computers Play Chess

A number of people are interested in problems of the “White to play and mate in two” variety. Although these problems are not really part of chess (since the positions are normally quite artificial) the same techniques that are used in chess programming could easily be employed to solve problems. In fact the Northwestern program has, for some time, announced mate whenever it detected a forced mate within its horizon. A program could be made to find all mates within a certain number of moves simply by performing an exhaustive search to the required depth, and for this reason such a program would be, in my opinion, of little value. (But that is because I dislike both chess problems and exhaustive searches). Some of the microprocessor machines described above already solve such problems.