Kasparou uersus DEEP BLUE Springer New York Berlin Heidelberg Barcelona Budapest Hong Kong London Milan Paris Santa Clara Singapore Tokyo Kasparou uersus DEEP BLUE COMPUTER CHESS COMES OF RGE ~ Monty Hewborn inger Library of Congress Cataloging-in-Publication Data Newborn, Monroe. Kasparov versus Deep Blue: computer chess comes of age / Monty Newborn. p. cm. Includes bibliographical references and index. ISBN-13: 978-1-4612-7477-3 e-ISBN-I3: 978-1-4612-2260-6 DOl: 10.1007/978-1-4612-2260-6 1. Computer chess. 2. Kasparov, G. K. (Garri Kimovich) I. Title. OV1449.3.N48 1996 794. 1 '72416-<1c20 96-24220 Printed on acid-free paper. © 1997 Springer-Verlag New York, Inc. Solleover reprint of the hardcover 1st edition 1997 All rights reserved. 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Photocomposed by Impressions Book and Journal Services, Inc., Madison, WI. 987654321 ~ Contents Preface 1uii foreword 1 Hi learning to fly 11 2 The foundations 17 3 Signs of Hope and Knlssn 135 4 Mnc HHCK and Transposition Tables 157 5 Horthwestern Uniuersity's [hess Program 173 6 Bmf and High·Speed [hess Circuitry I gl 7 [nny Bun and HmcH: Parallel Search and Parallel [ualuation 112g B [HIPHST. Om THOUGHT. and Om Bluf-and Garry KaspaTou 1147 g Om BlUf and Garry KaspaTou in Philadelphia 1235 10 The futuTe I 27g Rppendix R History of Major Computer Chess Championships 1283 Rppendix B Rules Gouerninq the RCM Chess Challenqe 1287 Rppendix C Dm BlUf Diary 12g3 Rppendix D Diary of Kasparou uersus Computers 1307 Rppendix f Rlqebraic Chess Hotation 1311 Index I 315 Preface his is a book about efforts to design a chess program that can defeat the Tworld's best human player. Today, that human is Garry Kasparov. He has been world champion for the last decade, winning the title from Anatoly Karpov, who reigned during the previous decade. Although Kas­ parov is thirty-two years old now, and in spite of the fact that there are sev­ eral young grandmasters chasing after him, his successful title defense against Vishwanathan Anand last year suggests that he may remain on top for a number of years to come; Mikhail Botvinnik, Kasparov's mentor, was over fifty and still world champion in the early 1960s. However, challenging Kasparov from a totally different direction are the best of mankind's computer creations. For almost fifty years, develop­ ing a world-class chess program has been a goal of the computer science community. Over this period of time, computers have continually im­ proved in strength, until today at least one program, IBM's DEEP BLUE, is on a par with the world's best players, perhaps not quite up to Kasparov, but not much behind either. This book attempts to chronicle progress in computer chess from the 1950s through the six-game ACM" Chess Challenge between Kasparov and DEEP BLUE in Philadelphia, in February of this year. Many games are presented; as is said, the proof is in the pudding. In Chapter 2, we begin by presenting the seminal work of Claude Shannon and Alan Turing. Some technical material on the minimax algo­ rithm and the alpha-beta algorithm is presented for those interested in un­ derstanding the programming or even perhaps interested in learning how to develop one's own program. For those without a technical background, this material can be skipped, as can similar technical material in several other early chapters. *The Association for Computing, which in its early days was known as the Association for Comput­ ing Machinery, hence ACM. uii ~ KRSPRHOU umus Om 8lUI The chess programs developed at MIT in the 1960s and at the Institute of Theoretical and Experimental Physics (ITEP) in Moscow are the subject of Chapter 3. The ITEP Program was first to demonstrate the effectiveness of Shannon's Type A strategy and the power of deeper search. KAISSA, a de­ scendent of the ITEP Program, was the first world champion chess program. In Chapter 4, Richard Greenblatt's MAC HACK is described. MAC HACK was the first program to compete successfully in human tournaments, do­ ing so for the first time in 1967. His program was also the first to use transposition tables to store chess positions as they were encountered in the search for later use, reducing the size of the search space that needed to be examined. Technical material on the way transposition tables are used in conjunction with alpha-beta search is presented. Chapter 5 is devoted to the greatest winning team in Northwestern University's history, the chess programming team of David Slate, Larry Atkin, and Keith Gorlen. Their program was the first to play expert-level chess and did so beginning in 1976, when it took first place in the Min­ nesota State Championship with a 5-1 score. Play by computers moved up to the next plateau, to that of master, in 1983, when BELLE was awarded that title by the United States Chess Feder­ ation (USCF). BELLE, developed by Ken Thompson with help from Joe Condon, used special-purpose circuitry to generate chess positions at a rate of 120,000 per second. Chapter 6 surveys Thompson's contributions to the field, including his work on opening books, special-purpose hardware, and endgame databases. The rules of chess were changed because of Thomp­ son's work on endgame databases. When defending its title as world champion in 1983, BELLE was de­ feated by Robert Hyatt, Bert Gower, and Harry Nelson's CRAY BLITZ. The power of the multiprocessor Cray computer was too much for BELLE. From then until 1985, CRAY BLITZ was the best chess program, but in 1985, and while still world champion, it was surpassed by Hans Berliner's HlTECH. CRAY BLITZ went on to retain its title at the 1986 world championship­ the first program to repeat as title holder-while HlTECH advanced to new levels of excellence against human competition. Chapter 7 surveys the ac­ complishments of these two programs. IBM's DEEP BLUE team has synthesized and modified the many ideas that have evolved over the years, adding some of their own, and creating a super-powerful machine; its rise to the top of the chess world is chronicled uiii ~ Preface in Chapter 8. The chapter records its exciting matches against some of the world's best humans and its ascendancy to the top of the computer world. Forty-one games played by DEEP BLUE are presented. Its two-game match in 1989 with Kasparov was the first formal match with a world champion. At the end of the same year it defeated international master David Levy, who had offered himself up as a milestone in the progress of chess programs. Two months later, it played a one-game match with Karpov, losing but putting up a good battle. In 1993, the IBM program showed that it had made signifi­ cant progress when it defeated Judit Polgar in a two-game match. Since 1987, it has been the best of the computer programs, winning the world championship in 1989 and dominating the ACM tournaments. It is about ten years old, and as great as has been its progress to date, its future progress may take it to unrivalled levels of play. Chapter 8 also includes seven en­ counters that Kasparov had against other programs: PENTIUM CHESS GENIUS, FRITZ 3, and FRITZ 4. These games were played at accelerated speeds. Chapter 9 presents the recent ACM Chess Challenge between Kas­ parov and DEEP BLUE. The six-game match attracted world-wide media at­ tention as Kasparov, losing the first game and then playing very cautiously for the next four games, won the match with a 4-2 score. Kasparov won a purse of $400,000 for a hard week of work-much harder than he ever imagined when he accepted the challenge. The concluding chapter, Chapter 10, examines the implications of progress in computer chess for the future of chess and computing. My own role has been as a participant, organizer, and author over the years. In 1970, Ken King, then the director of the Columbia University computer center, and I, then an assistant professor in Columbia's Depart­ ment of Electrical Engineering and Computer Science, organized the first chess tournament exclusively for computers as part of the ACM annual conference at the New York Hilton. Named the United States Computer Chess Championship, the event featured six programs and loud laughter from the experts in the audience. The next year, I assisted Ben Mittman, the director of Northwestern University's Vogelback Computer Center, in orga­ nizing the second U.S. Computer Chess Championship, and the two of us went on to organize events around the world over the next fifteen years. In 1977, the International Computer Chess Association (ICCA) was formed. Mittman initially served as president and I as vice-president; later, from 1983-1986, I served as president.