Table Of ContentACM MONOGRAPH SERIES
Published under the auspices of the Association for
Computing Machinery Inc.
Editor THOMAS A. STANDISH University of California at Irvine
Former Editors
Richard W. Hamming, Herbert B. Keller, Robert L. Ashenhurst
A. FINERMAN (Ed.) University Education in Computing Science, 1968
A. GINZBURG Algebraic Theory of Automata, 1968
E. F. CODD Cellular Automata, 1968
G. ERNST AND A. NEWELL GPS: A Case Study in Generality and
Problem Solving, 1969
M. A. GAVRILOV AND A. D. ZAKREVSKII (Eds.) LYaPAS: A Programming
Language for Logic and Coding Algorithms, 1969
THEODOR D. STERLING, EDGAR A. BERING, JR., SEYMOUR V. POLLACK,
AND HERBERT VAUGHAN, JR. (Eds.) Visual Prosthesis:
The Interdisciplinary Dialogue, 1971
JOHN R. RICE (Ed.) Mathematical Software, 1971
ELLIOTT I. ORGANICK Computer System Organization: The B5700/B6700
Series, 1973
NEIL D. JONES Computability Theory: An Introduction, 1973
ARTO SALOMAA Formal Languages, 1973
HARVEY ABRAMSON Theory and Application of a Bottom-Up Syntax-
Directed Translator, 1973
GLEN G. LANGDON, JR. Logic Design: A Review of Theory and Practice,
1974
MONROE NEWBORN Computer Chess, 1975
ASHOK K. AGRAWALA AND TOMLINSON G. RAUSCHER Foundations of Mi
croprogramming: Architecture, Software, and Applications, 1975
P. J. COURTOIS Decomposability: Queueing and Computer System Appli
cations, 1977
JOHN R. METZNER AND BRUCE H. BARNES Decision Table Languages and
Systems, 1977
ANITA K. JONES (Ed.) Perspectives on Computer Science: From the 10th
Anniversary Symposium at the Computer Science Department, Carne
gie-Mellon University, 1978
DAVID K. HSIAO, DOUGLAS S. KERR, AND STUART E. MADNICK Computer
Security, 1979
ROBERT S. BOYER AND J STROTHER MOORE A Computational Logic, 1979
J. F. TRAUB AND H. WOZNIAKOWSKI A General Theory of Optimal
Algorithms, 1980
In preparation
R. L. WEXELBLAT History of Programming Languages
Computer Chess
Monroe Newborn
Department of Electrical Engineering
and Computer Science
Columbia University
New York, New York
ACADEMIC PRESS New York San Francisco London 1975
A Subsidiary of Harcourt Brace Jovanovich, Publishers
COPYRIGHT © 1975, BY ACADEMIC PRESS, INC.
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Library of Congress Cataloging in Publication Data
Newborn, Monroe.
Computer chess.
(A.C.M. monograph series)
Includes bibliographical references and index.
1. Electronic data processing-Chess. 2. Chess
Tournaments. I. Title. II. Series: Association for
Computing Machinery. ACM monograph series.
GV1318.N48 794.1'7 74-17965
ISBN 0-12-517250-8
PRINTED IN THE UNITED STATES OF AMERICA
81 82 9 8 7 6 5 4
Preface
A digital computer conquered its first human opponent across the
chess board in 1956. Since then, the quality of play by computers has im
proved remarkably and today they are playing on a par with good high
school players. Their style of play is quite different from that of humans.
There is an obvious lack of long-range planning that becomes glaringly
apparent in end-game play. Computers typically look two to four full
moves ahead and make moves based on the information gained in the
lookahead. If trouble lurks one move beyond the lookahead, it goes
undetected. What went undetected on one move may loom up on the
next move as does an iceberg before a ship at sea in a fog. Computers
do, however, play good tactical chess; to some degree this makes up for
their shortcomings in long-range planning.
The aim of this book is twofold: first, to provide the reader with a
comprehensive history of computer chess games, and second, to give him
an insight into the programming of computer chess. Chapter II presents
the historical background of the basic ideas underlying computer chess
and several of the earliest games. Chapters III-IX and Appendix I pro
vide a record of the more recent games. Most of the games were played
between two computers, but computer versus human games have been
included when no other games were available (in the cases of early
programs) or when games are of particular significance (Mac Hack Six
and KAISSA). The author has been involved in the organization of the
four United States Computer Chess Championships and attempts to pro-
ix
X Preface
vide a detailed description of events surrounding these tournaments.
Chapter X outlines OSTRICH, a chess program developed by George
Arnold and the author.
An individual interested in developing a chess program should be
able to do so after digesting the material in Chapters II and X, assuming
he has an adequate programming background. About two months of in
tensive effort are necessary in order to get a minimal working program.
There are over forty chess programs in existence today, and the number
is increasing rapidly both in the United States and abroad (Norway,
Austria, the U.S.S.R., England, Hungary, Switzerland, Germany, and
Canada. In the future there may be a library of subprograms available
to interested individuals; this should reduce the amount of repeated
effort.
For the chess expert, this book will do little to improve his tech
nique. If he has not observed computers at play in the last few years,
however, he will be surprised by the quality of the better games. Most
exciting is the success of the Soviet program KAISSA in its recent match
against the readers of Komsomolskaia Pravda, a Russian daily newspaper.
The First, Second, Third, and Fourth United States Computer Chess
Championships were part of the Association for Computing Machinery's
Annual Conferences of 1970-1973. The Fourth took place recently in
Atlanta, Georgia on August 26-28, 1973. These tournaments, hosted by
the ACM, and partially supported in the past by the Control Data Corpo
ration, International Business Machines, Sperry-UNIVAC, National Data
Industries, and Western Electric, have provided a meeting ground for
those interested in computer chess programs and in the broader field of
artificial intelligence.
Acknowledgments
The author would like to thank the many people who have offered
suggestions and provided help in the preparation of this manuscript.
Most particularly, George Arnold, Nadim Habra, Allen Reiter, and Israel
Gold have been most willing editors and critics and are due special
thanks. The author would also like to thank the Department of Electrical
Engineering and Computer Science at Columbia University and the De
partment of Computer Science at the Technion, Haifa, for providing
assistance in the preparation of the manuscript. Finally, a special thanks
is extended to Miss Sadie Silverstein for her many hours of patient and
gracious help in typing the manuscript.
Grateful acknowledgment is given to the following for permission
to quote material as specified:
AFIPS Press, for the listing of moves in one of the computer chess games
reported in Greenblatt, R., and Crocker, S., The Greenblatt chess program, Proc.
Fall Joint Computer Conf., 801-810, 1967.
Association for Computing Machinery, for the listing of moves and related com
ments in the computer chess game, the Los Alamos Chess Program versus Beginner,
which appears in Kister, J., et al., Experiments in chess, J ACM 4, 174-177, 1967,
and for other games that appear in issues of the SIGART Newsletter of the ACM.
Daphne Productions, for Bobby Fischer's views on computer chess as voiced on
the Dick Cavett Television Show, December 21, 1972.
Edinburgh University Press, for the listing of moves in the computer chess
game reported in Good, I.J., Analysis of a machine chess game, J. Scott (White),
ICL-1900 versus R. D. Greenblatt, PDP-10, Machine Intelligence, 267-269, 1969.
W. H. Freeman and Co., for the listing of moves and related comments in the
xi
xii Acknowledgments
computer chess game that appears in Bernstein, A., and Roberts, M. de V., Com
puter v. chess player, Scientific American, 96-105, June 1958.
IEEE, for the "decision routines" in Bernstein, A., et al, A chess playing pro
gram for the IBM 704, Proc. Western Joint Computer Conf., 157-159, March 1959.
MIT Press, for extracts from Wiener, N., "Cybernetics," pp. 164, 165 (1948).
Pitman and Sons, Ltd., for the listing of moves and related comments in
Turing's chess game reported in Turing, A., Digital computers applied to games,
in "Faster Than Thought" ( B. V. Bowden, ed.). (1953).
United States Chess Federation, for the listing of moves in the Napoleon
versus Turk game, which appears in Harkness, K., and Battell, J., This made chess
history, Chess Rev., November 1947.
CHAPTER I
Introduction
From the very beginning of the development of digital computers,
researchers recognized their potential for solving complex problems.
They conceived of their use in processing natural languages, in par
ticular, in translating from one language to another. They saw computers
being programmed to prove mathematical theorems, to simulate economic
systems, to aid in the diagnosis of medical illnesses, to predict the
weather, and to design other computers. They even imagined computers
programmed to compose music and to write poetry. Many outstanding
researchers also touched upon the game of chess.
Chess has many features that make it an excellent problem for those
interested in studying how computers might be programmed to solve
other complex problems. The rules are well defined, including the defini
tions of a win, a loss, and a draw. There is no element of chance; all the
cards, so to speak, are on the table. It is a game of perfect information. In
theory, given enough time, a computer can examine all possible continu
ations from a given position and can always find the best move to make.
However, and here is what makes computer chess an excellent problem,
this is usually not possible in practice because of the tremendous number
of continuations that exist in most positions. Thus a computer can do little
more than selectively search several moves ahead into the tree of all pos
sible continuations using chess heuristics'* to guide the search. It must
* A chess heuristic might be defined as a chess rule of thumb. For example, one
chess heuristic is this: avoid moving the King from the first rank early in the game.
In general, this is a good policy, but there are times when it is best to move the King
from the back row early in the game. This heuristic, like most others, is dangerous to
follow with absolute faith.
1
2 I. Introduction
decide which move to make based on this nearsighted look-ahead. A move
is said to be determined by a finite-depth heuristic tree-searching pro
cedure. Most programs that do language processing, theorem proving,
medical diagnosis, and computer circuit design include heuristic tree-
searching procedures. And while a chess program is similar in structure
to these programs, it has one particularly convenient feature: one can ob
tain a fairly accurate measure of a program's strength by pitting it against
human opponents—or against other computers—of known strength.*
Over the last twenty years computer chess programs have been writ
ten, and games pitting computer versus man and computer versus com
puter have been played. The best programs presently play at a level of
mediocre club players or at the level of good high school players. The
newer programs are better than the old, with the improvement primarily
due to advances in computer hardware and software and to more thorough
programming efforts rather than to any new fundamental breakthroughs
in how to program computers to play better. Due to hardware advances,
today's computers are several hundred times faster than they were when
chess programs were first written. Software advances make the editing and
debugging of programs orders of magnitude easier than it was at first.
Bobby Fischer had the following to say when asked about the possi
bilities of computer chess on the Dick Cavett Television Show on Decem
ber 21, 1972:
Yes, I believe that it is possible (in principle) for me to be beaten by
a computer. . . But they have a long way to go. They're only playing at the
class B level, which is five or six levels below me. And up to now they've
only had computer scientists developing such programs, and they won't go
anywhere until they actually involve some good chess players.
Fischer was well aware of the level of play by computers (and even
may have been a little charitable), but he was a bit unfair when he im
plied that no good chess players were involved. Some of the best chess
players in the United States are involved, as well as one former world
champion from the Soviet Union.
The most outstanding chess player in the United States to have written
a chess program so far is Hans Berliner. Berliner was World Correspon
dence Chess Champion several years ago. He is presently a doctoral stu
dent at Carnegie-Mellon University in Pittsburgh in the field of computer
science. David Slate, rated an expert by the USCF, has been behind the
Northwestern University program, which has won the United States Com-
* Most good chess players in the USA have United States Chess Federation
(USCF) ratings, as do several computers.
I. Introduction 3
puter Chess Championship for the last four years. Charles Kalme, one of the
top fifty chess players in the United States, has been assisting a group at the
University of Southern California. In the Soviet Union, Mikhail Botvinnik,
world champion from 1948 to 1963 (with the exceptions of 1957 and 1960
when Vassily Smyslov and Mikhail Tal were champions, respectively),
has been developing a chess program for several years with the help of
a colleague, V. Butenko, based on ideas presented in his book "Computers,
Chess, and Long-Range Planning."
That no program presently plays at the Master level is not at all sur
prising to anyone closely involved. On the other hand, the prospects for
the future look quite good. No presently functioning program has been in
existence for more than six years. A minimum of fifteen years of intensive
work by an excellent programer and chess player seems necessary to write
a program that might compete with Masters. Many hours of programming
and many hours of observation and analysis of the resulting play
are required. Additionally, there will be several developments that should
make the task easier. The computers of tomorrow will be much faster than
present ones; a speedup by a factor of several hundred in the next fifteen
years is not too unreasonable to expect. This will allow much larger move
trees to be searched. Chess programs of the future will also make use of
very large files of stored book openings, which will allow computers to
play each of the first ten to fifteen moves of a game in a matter of several
seconds, leaving more time for the complex middle game. Special end
game programs will also be developed by one individual or group and
will be made available to other groups.* Thus, with fifteen years of work
by someone who is an outstanding chess player and programmer and with
computers several hundred times faster than they are today, and with the
sharing of special programs, it seems quite possible to develop a chess pro
gram that will compete on an even footing with a Master without any new
breakthroughs in the field.
What will happen to the game of chess if and when computers are
capable of playing on a level with Masters, or even perhaps on a level
with Bobby Fischer, as he himself concedes is possible? Will the game
die? Will people lose interest? No, that will not happen. Instead, a new
era in the history of chess will emerge, an era in which the game is not
playing chess but programming computers to play. Programs will have
their own individal "personalities" and will reflect the chess styles of their
authors. This revolution in the chess world lies somewhere in the future—
the new game will be far more exciting than the old!
* See, for example, Barbara J. Huberman, "A Program to Play Chess End
Games," Stanford Univ. Tech. Rept. CS 106, August 19, 1968.
