Human–computer chess matches

This article documents the progress of significant human-computer chess matches.

Chess computers were first able to beat strong chess players in the late 1980s. Their most famous success was the victory of Deep Blue over then World Chess Champion Garry Kasparov in 1997, but there was some controversy over whether the match conditions favored the computer.

In 2002–2003 three human-computer matches were drawn. But whereas Deep Blue was a specialized machine, these were chess programs running on commercially available computers.

After convincing victories in two matches in 2005 and 2006, it appears that chess programs can now defeat even the strongest chess players.

David Levy's bet (1978)

Main article: David Levy (chess player) § Computer chess bet

For a long time in the 1970s and 1980s it remained an open question whether any Chess program would ever be able to defeat the expertise of top humans. In 1968, International Master David Levy made a famous bet that no chess computer would be able to beat him within ten years. He won his bet in 1978 by beating Chess 4.7 (the strongest computer at the time), but acknowledged then that it would not be long before he would be surpassed.

The Aegon Man-Machine Tournaments (1986–1997)

The 12 Aegon Man-Machine Tournaments were held annually from 1986 to 1997. The Dutch Computer Chess Federation (CSVN) organized the Aegon Man-Machine Tournaments in The Hague, Netherlands. The Aegon insurance company hosted the tournaments. An equal number of humans and computers played a 6 round swiss tournament with all games between humans and computers. The early tournaments were mostly local players and anti-computer tactics specialists. Later tournaments included masters and grandmasters. In the early tournaments, humans won more games. In the later tournaments, computers won more games.

100 players played in the 1997 tournament. Computers won 151 ½ points. Humans won 148 ½ points. Yona Kosashvili scored highest for the humans at 6 points out of 6 games. Kallisto scored highest for the computers at 4 ½ points.

Deep Thought (1989)

In 1988, Deep Thought shared first place with Tony Miles in the Software Toolworks Championship, ahead of a former world champion Mikhail Tal and several grandmasters including Samuel Reshevsky, Walter Browne, Ernst Gruenfeld and Mikhail Gurevich. It also defeated grandmaster Bent Larsen, making it the first computer to beat a grandmaster in a tournament. Its rating for performance in this tournament of 2745 (USCF scale).

In 1989, Levy was defeated by the computer Deep Thought in an exhibition match.

Deep Thought, however, was still considerably below World Championship Level, as the then reigning world chess champion Garry Kasparov demonstrated in two convincing wins in 1989.

Chess Genius (1994)

The "Chess Genius" program was entered into a Professional Chess Association rapid chess tournament in 1994. It defeated and eliminated world champion Kasparov, but lost to Viswanathan Anand in the next round. This was the first time a computer had defeated the world champion in an official game, albeit at rapid time controls.

Kasparov – Deep Blue (1996-1997)

1996

Deep Blue vs. Kasparov 1996, game 1.

	a	b	c	d	e	f	g	h
8									8
7									7
6									6
5									5
4									4
3									3
2									2
1									1
	a	b	c	d	e	f	g	h

The final position.

Main article: Deep Blue versus Garry Kasparov

Kasparov played a six game match against IBM's Deep Blue in 1996. Kasparov lost the first game (Deep Blue – Kasparov, 1996, Game 1), the first time a reigning world champion had lost to a computer using regular time controls. However, Kasparov regrouped to win three and draw two of the remaining five games of the match, for a convincing 4–2 match victory.

1997

In May 1997, an updated version of Deep Blue defeated Kasparov 3½–2½ in a highly publicised six-game match. He won the first, lost the second, and drew the next three. The match was even after five games but Kasparov was crushed in Game 6. This was the first time a computer had ever defeated a world champion in match play. A documentary film was made about this famous match-up entitled Game Over: Kasparov and the Machine. In that film Kasparov casually says, "I have to tell you that, you know, game two was not just a single loss of a game. It was a loss of the match, because I couldn't recover."

It should be noted however, that in game 6, Kasparov blundered very early into the game. Kasparov cites tiredness and unhappiness with the IBM team's conduct at the time as the main reason.

Kasparov claimed that several factors weighed against him in this match. In particular, he was denied access to Deep Blue's recent games, in contrast to the computer's team that could study hundreds of Kasparov's.

After the loss Kasparov said that he sometimes saw deep intelligence and creativity in the machine's moves, suggesting that during the second game, human chess players, in contravention of the rules, intervened. IBM denied that it cheated, saying the only human intervention occurred between games. The rules provided for the developers to modify the program between games, an opportunity they said they used to shore up weaknesses in the computer's play revealed during the course of the match. Kasparov requested printouts of the machine's log files but IBM refused, although the company later published the logs on the Internet. Kasparov demanded a rematch, but IBM refused and dismantled Deep Blue.

Kasparov maintains that he was told the match was to be a scientific project but that it soon became apparent that IBM wanted to beat him and nothing more.

Anand – REBEL (1998)

With increasing processing power, Chess programs running on regular workstations began to rival top flight players. In 1998, Rebel 10 defeated Viswanathan Anand who at the time was ranked second in the world, by a score of 5–3. However most of those games were not played at normal time controls. Out of the eight games, four were blitz games (five minutes plus five seconds Fischer delay (see time control) for each move) these Rebel won 3–1. Then two were semi-blitz games (fifteen minutes for each side) which Rebel won as well (1½–½). Finally two games were played as regular tournament games (forty moves in two hours, one hour sudden death) here it was Anand who won ½–1½. At least in fast games computers played better than humans but at classical time controls — at which a player's rating is determined — the advantage was not so clear.

Kramnik – Deep Fritz (2002)

In October 2002, Vladimir Kramnik (who had succeeded Kasparov as Classical World Chess Champion) and Deep Fritz competed in the eight-game Brains in Bahrain match, which ended in a 4–4 draw.

Kramnik was given several advantages in his match against Fritz when compared to most other Man vs. Machine matches, such as the one Kasparov lost against Deep Blue in 1997. The code of Fritz was frozen some time before the first match and Kramnik was given a copy of Fritz to practice with for several months. Another difference was that in games lasting more than 56 moves, Kramnik was allowed to adjourn until the following day, during which time he could use his copy of Fritz to aid him in his overnight analysis of the position.

Kramnik won games 2 and 3 by "conventional" anti-computer tactics — play conservatively for a long-term advantage the computer is not able to see in its game tree search. Fritz, however, won game 5 after a severe blunder by Kramnik. Game 6 was described by the tournament commentators as "spectacular." Kramnik, in a better position in the early middlegame, tried a piece sacrifice to achieve a strong tactical attack, a strategy known to be highly risky against computers who are at their strongest defending against such attacks. True to form, Fritz found a watertight defense and Kramnik's attack petered out leaving him in a bad position. Kramnik resigned the game, believing the position lost. However, post-game human and computer analysis has shown that the Fritz program was unlikely to have been able to force a win and Kramnik effectively sacrificed a drawn position. The final two games were draws. Given the circumstances, most commentators still rate Kramnik the stronger player in the match.

Kasparov – Deep Junior (2003)

In January 2003, Kasparov engaged in a six game classical time control match with a $1 million prize fund which was billed as the FIDE "Man vs. Machine" World Championship, against Deep Junior. The engine evaluated three million positions per second. After one win each and three draws, it was all up to the final game. The final game of the match was televised on ESPN2 and was watched by an estimated 200–300 million people. After reaching a decent position Kasparov offered a draw, which was soon accepted by the Deep Junior team. Asked why he offered the draw, Kasparov said he feared making a blunder. Originally planned as an annual event, the match was not repeated.

Kasparov – X3D Fritz (2003)

In November 2003, Kasparov engaged in a four-game match against the computer program X3D Fritz (which was said to have an estimated rating of 2807), using a virtual board, 3D glasses and a speech recognition system. After two draws and one win apiece, the X3D Man-Machine match ended in a draw. Kasparov received $175,000 for the result and took home the golden trophy. Kasparov continued to criticize the blunder in the second game that cost him a crucial point. He felt that he had outplayed the machine overall and played well. "I only made one mistake but unfortunately that one mistake lost the game."

Man vs Machine World Team Championship (2004-2005)

The Man vs Machine World Team Championships were two chess tournaments in Bilbao, the Basque region of Spain. A second name for the tournaments is the People vs. Computers World Team Matches.

2004

In October 2004, Ruslan Ponomariov, Veselin Topalov and Sergey Karjakin played against computers Hydra, Fritz 8, and Deep Junior. Ponomariov and Topalov were FIDE world chess champions. Sergey Karjakin at 12 was the youngest Grandmaster. The computers won 8.5 to 3.5. The humans won one game, Karjakin, the youngest and lowest rated player, defeated Deep Junior.

• Ponomariov – Hydra 0–1
• Fritz – Karjakin 1–0
• Deep Junior – Topalov 1/2–1/2
• Karjakin – Deep Junior 1–0
• Ponomariov – Fritz 1/2–1/2
• Topalov – Hydra 1/2–1/2
• Deep Junior – Ponomariov 1/2–1/2
• Hydra – Karjakin 1–0
• Fritz – Topalov 1–0
• Hydra – Ponomariov 1–0
• Karjakin – Fritz 0–1
• Topalov – Deep Junior 1/2–1/2

2005

In November 2005, 3 former FIDE world chess champions, Alexander Khalifman, Ruslan Ponomariov and Rustam Kasimdzhanov played against computers Hydra, Junior and Fritz. The computers won 8 to 4.

• Ponomariov – Junior 0–1
• Hydra – Kasimdzhanov 1–0
• Fritz – Khalifman 1–0
• Ponomariov – Fritz 1–0
• Kasimdzhanov – Junior 1/2–1/2
• Khalifman – Hydra 1/2–1/2
• Hydra – Ponomariov 1–0
• Fritz – Kasimdzhanov 1/2–1/2
• Junior – Khalifman 1–0
• Ponomariov – Junior 1/2–1/2
• Kasimdzhanov – Hydra 1/2–1/2
• Khalifman – Fritz 1/2–1/2

Hydra – Adams (2005)

In 2005, Hydra, a dedicated chess computer with custom hardware and sixty-four processors and also winner of the 14th IPCCC in 2005, crushed seventh-ranked Michael Adams 5½–½ in a six-game match. While Adams was criticized for preparing less well than Kasparov and Kramnik had, some commentators saw this as heralding the end of human-computer matches.

Kramnik – Deep Fritz (2006)

Kramnik, then still the World Champion, played a six-game match against the computer program Deep Fritz in Bonn, Germany from November 25 to December 5, 2006, losing 0–4–2 to the machine, with two losses and four draws. He received 500,000 Euros for playing and would have received another 500,000 Euros had he won the match. Deep Fritz version 10 ran on a computer containing two Intel Xeon CPUs (a Xeon DC 5160 3 GHz processor with a 1333 MHz FSB and a 4MB L2 Cache) and was able to evaluate eight million positions per second. Kramnik received a copy of the program in mid-October for testing, but the final version included an updated opening book. Except for limited updates to the opening book, the program was not allowed to be changed during the course of the match. The endgame tablebases used by the program were restricted to five pieces even though a complete six-piece tablebase is widely available. While Deep Fritz was in its opening book Kramnik is allowed to see Fritz’s display. The Fritz display contains opening book moves, number of games, Elo performance, score from grandmaster games and the move weighting.

In the first five games Kramnik steered the game into a typical "anti-computer" positional contest. On November 25, the first game ended in a draw at the 47th move. A number of commentators believe Kramnik missed a win. Two days later, the second game resulted in a victory for Deep Fritz, when Kramnik made what might be called the "blunder of the century" according to Susan Polgar, when he failed to defend against a threatened mate-in-one in an even position. (see also Deep Fritz v. Vladimir Kramnik blunder). The third, fourth and fifth games in the match ended in draws.

In the final game, in an attempt to draw the match, Kramnik played the more aggressive Sicilian Defence and was crushed., losing the match 4–2.

There was speculation that interest in human-computer chess competition would plummet as a result of the 2006 Kramnik–Deep Fritz match. According to McGill University computer science professor Monty Newborn, for example, "the science is done".

Rybka odds matches (2007-2008)

Since 2007 Rybka has played some odds matches against grandmasters. Jaan Ehlvest first lost a pawn-odds match, then later lost a match when given time, color, opening, and endgame advantages. Roman Dzindzichashvili then drew a match when given pawn and move odds.

In September 2008, Rybka played an odds match against Vadim Milov, its strongest opponent yet in an odds match. (Milov at the time had an Elo rating of 2705, 28th in the world). The result was a narrow victory to Milov: He had won 1½–½ when given pawn-and-move, and 2½–1½ (1 win, 3 draws) when given exchange odds but playing black. In two standard games (Milov had white, no odds), Rybka won 1½–½.

Pocket Fritz 4 (2009)

Chess engines continue to improve. In 2009 a chess engine running on slower hardware, a mobile phone, reached the grandmaster level. The mobile phone won a category 6 tournament with a performance rating 2898. The chess engine Hiarcs 13 runs inside Pocket Fritz 4 on the mobile phone HTC Touch HD. Pocket Fritz 4 won the Copa Mercosur tournament in Buenos Aires, Argentina with 9 wins and 1 draw on August 4–14, 2009. Pocket Fritz 4 searches less than 20,000 positions per second. This is in contrast to supercomputers such as Deep Blue that searched 200 million positions per second. Pocket Fritz 4’s higher performance comes from being smarter and not from faster computers.