Chess x.x Chess Program
Before
there was Vasik Rajlich and
Rybka, before there was IBM and Deep Thought and Deep
Blue, there was the Slate/Atkin program called Chess x.x.
Chess x.x (Chess 2.0 to 4.9) was the modified version of the
chess program Chess, which was a computer
program written in assembly language at Northwestern University (Vogelback Computing Center) in Evanston, Illinois by David J.
Slate, Larry R. Atkin, and Keith Gorlen.
The program later received support from Dr.
David Cahlander of Control Data Corporation (CDC) in
Minneapolis, a CDC Cyber hardware consultant.
In
1968, undergraduates Larry Atkin and Keith Gorlen decided to write a chess program to exercise Northwestern
University’s new CDC 6400 mainframe computer ( a
slower and cheaper version of the CDC 6600 supercomputer, the world’s fastest
computer at the time – 3 million instructions per second). Upon hearing of their work, physics graduate
student David Slate (rated around 2050) decided to write a competing
program. They combined their programs in
October 1969, and produced Chess 2.0.
In
1970, Slate received a letter containing suggestions for improving Chess 2.0
from International Master David Levy, who had tested the program at the
University of London. Improvements were
made and the new release was now called Chess 3.0. Chess 3.0 was now more efficient and running
65% faster than Chess 2.0.
Chess
3.0 through 4.9 was one of the most successful chess programs during the 1970s.
Chess was the first published use of the
bitboard data structure applied to the game of
chess. Each bit represented a game
position or state, designed for optimization of speed and/or memory or disk use
in mass calculations. The first bit
represents the a1 square and the 64th bit represents the h8 square.
In
September 1970, Chess 3.0 won the first Association for Computing Machinery
(ACM) U.S. Computer Chess Championship in New York. Chess 3.0 ran on a CDC 6400 and won all of
its three games. There were 6 programs
in the event.
Gorlen left Northwestern in 1970, but Slate and Atkin
continued to work of their chess program.
In
1971, Chess 3.5 won the 2nd annual ACM event in Chicago, winning all
of its three games. There were 8
programs in the event.
In 1972,
Chess 3.6 won the 3rd ACM tournament in Boston, scoring 3-0. There were 8 programs.
In
1973, Slate and Atkin wrote a new program, Chess 4.0,
rather than modifying the Chess 3.x series. A library of 5,000 opening
positions was added.
In
1973, Chess 4.0 won the 4th ACM tournament in Atlanta. It won 3 games and drew 1 game. There were 12 programs.
A major
turning point from Chess 3.0 to Chess 4.0 was the transition to full-width
search and brute-force search to take advantage of the speed and computational
capacity in the new computers.
In
January 1974, Chess 4.0 played in a chess tournament with 50 humans at
Northwestern University. It tied for 3rd
place, scoring 4.5 out of 6. Its
performance rating was 1736.
In
1974, Chess 4.0 participated in the first world computer chess championship in
Stockholm, scoring 3 wins and 1 loss (losing to Chaos). The event was won the USSR program Kaissa. There were
13 programs in the event. After the
event Chess 4.0 played one game against Kaissa, which
was drawn.
In
1974, Chess 4.2 failed to win the 5th ACM U.S. Computer Chess
Championship, held in San Diego. The
University of Waterloo program RIBBIT (later call TREEFROG) won that event by
defeating Chess 4.2.
On
October 21, 1975, Chess 4.4 won the 6th ACM North American Computer
Chess Championship (NACCC) event in Minneapolis with a perfect 4-0 score, using
the faster CDC Cyber 175 computer (2.1 megaflops). There were 12 programs in the event. It was estimated that a doubling in computer
speed increased playing strength by about 100 points.
In
1976, Slate and Atkin added a transposition table for
Chess 4.5. Its rating was under 1600, or
Class C level. After 10 years of
development, chess programs gained less than 200 points. At that rate, it would take another 60 years
before a computer could challenge the world chess champion. But in just a few years, Chess 4.9 would be
playing at the Expert level.
On July
25, 1976, Chess 4.5 (rated 1579) won the Class B section of the 4th Paul
Masson chess tournament
in Saratoga, California with a perfect 5-0 score. It had a performance rating of 1950. This event was the first time any machine
performed successfully in a tournament for humans and won a prize ($700, but
was turned down by the programmers).
After the event, Chess 4.5 was rated 1722.
In October 1976,
Chess 4.5 won the 7th ACM NACCC tournament in Houston. Chess 4.5 was searching trees with 800,000 nodes per move using a CDC CYBER 176
(4.6 megaflops). It could look at 1,500
positions per second.
On
February 20, 1977, Chess 4.5 won the 84th Minnesota Open
Championship with 5 wins and 1 loss. It
defeated one expert, Charles Fenner, rated 2016 and
lost to Walter Morris, rated 2175. Its
performance rating was 2271. Chess 4.5
then qualified for the Minnesota State Championship, but did not win it.
In
March 1977, Chess 4.5 gave a simultaneous exhibition in New York, winning 8,
drawing 1, and losing 1 (to Eric Bone – 2150).
It then played 4 games of blitz chess against International Master David
Levy, winning 2 and losing 2. Its blitz
performance rating was 2300.
On August
9, 1977, Chess 4.6 won the second World Computer Chess Championship, held in
Toronto. There were 16 participating
programs from 8 countries, including defending champion Kaissa
of the USSR. It won with a 4-0 score,
defeating BCP, Master, Duchess, and Belle.
2nd place went to Duchess. In a
special exhibition the next day, Chess 4.6 beat Kaissa.
In October
1977, Chess 4.6 tied for 1st place with Duchess at the 8th
ACM North American Computer Chess Championship, held in Seattle. Both scored 3.5 points out of 4. The winning trophy was awarded to Chess 4.6
base on tie-breaking points.
In
September 1977, Chess 4.6 achieved a 2000 rating in a tournament in
London. On September 18, 1977 it was the first computer to beat a
grandmaster when it defeated GM Michael Stean in
London.
On
April 30, 1978, Chess 4.6 won the Twin Cities Open in Minneapolis with a
perfect 5-0 score. Going into the event,
the program had a USCF rating of 1936.
After the event, its rating was 2040.
On May
6, 1978, Chess 4.6 defeated U.S. chess champion Walter Browne (2560) at a 44-board
simultaneous exhibition in Minneapolis.
Chess 4.6 was running on a Control Data Corporation (CDC) Cyber 176
supercomputer and examining 2.5 million positions in three minutes of think
time. Browne was the first grandmaster
to lose a game of chess from a computer, but it was a simultaneous exhibition
and not a normal tournament with time controls.
In
August 1978, Chess 4.7 played a 6-game challenge match with David Levy (2350)
for his famous bet in Toronto that no chess computer could beat him in a match
by 1984 (he later won his bet). Chess
4.7 did not defeat Levy in the match, but it did beat him in game 4. Levy became the first International Master to
lose a game to a computer in a tournament environment.
In
October 1978, the 9th ACM NACCC tournament was held in Washington,
DC. Belle won the event. Chess 4.7 came in 2nd place.
In
October 30,1979, Chess 4.9 won the 10th ACM
NACCC tournament in Detroit and was consistently playing at the expert level
(2100).
In
1979, Chess 4.9 played in the 3rd world chess championship in
Linz. There were 18 participating
programs. Chess 4.0 score 2.4 out of 4
games. The event was won by Belle.
In
1980, Chess 4.9 drew a game with Larry D. Evans (2393) at the U.S. Amateur Team
Championship. Chess 4.9 had a
performance rating of 2168. In speed
chess, Chess 4.9 performed at a 2300 Elo rating. Grandmaster Fridrik
Olafsson had not trouble in defeating Chess 4.9 in
two blitz games that year.
By the
end of 1980, Chess 4.9 was retired from competition after Slate teamed up with
William Blanchard to create NUCHESS. Atkin went to Applied Concepts and worked on dedicated
chess computers such as the Great Game Machine and the Chafitz
modular game system.
The
Slate/Atkin program remained the best chess-playing
program throughout the 1970s. It gained
chess strength and rating with each new, faster generation of computer
hardware. For every fivefold increase in
computer speed, there was a 200 point increase in the program’s rating as it
approached the master rating level of 2200.
References:
Atkinson, Chess and
Machine Intuition
Botvinnik, Computers in Chess
Frey, Chess Skills in Man
and Machine
Hsu, Behind Deep Blue
Levy, The Chess Computer Handbook
Levy, Computer Chess Compendium
Levy and Newborn, How
Computers Play Chess
Marsland & Schaeffer, Computers,
Chess and Cognition
Newbor, Computer Chess
Welsh, Computer Chess I
and II
Welsh & Baczynskyj, Computer Chess II
Wall, ACM Computer Chess http://www.geocities.com/SiliconValley/Lab/7378/acm.htm
Wall, Computer Chess History http://www.geocities.com/siliconvalley/lab/7378/comphis.htm