'Deep Blue' was IBM's chess playing computer. Deep Blue was the first computer system to win a chess game against a reigning world champion, Garry Kasparov, under regular time controls. This first win occurred on February 10, 1996, and Deep Blue - Kasparov, 1996, Game 1 is a famous chess game. However, Kasparov won 3 games and drew 2 of the following games, beating Deep Blue by a score of 4-2.
Deep Blue was then heavily upgraded and played Kasparov again in May 1997, winning the six-game rematch 3.5-2.5, ending on May 11th. Deep Blue thus became the first computer system to defeat a reigning world champion in a match under standard chess tournament time controls.
The project was started as "ChipTest" at Carnegie Mellon University by Feng-Hsiung Hsu; the computer system produced was named Deep Thought after the fictional computer of the same name from The Hitchhiker's Guide to the Galaxy. Hsu joined IBM in 1989 and worked with Murray Campbell on parallel computing problems. Deep Blue was developed out of this.
The system derives its playing strength mainly out of brute force computing power. It is a massively parallel, 30-node, RS/6000, SP-based computer system enhanced with 480 special purpose VLSI chess processors. Its chess playing program is written in C and runs under the AIX operating system. It is capable of evaluating 100,000,000 positions per second.
Its evaluation function was initially written in a generalized form, with many to-be-determined parameters (e.g. : how important is a safe king position compared to a space advantage in the center, etc.). The optimal values for these parameters were then determined by the system itself, by analyzing thousands of master games. Before the second match, the chess knowledge of the program was fine tuned by grandmaster Joel Benjamin. The opening library was provided by the grandmasters Miguel Illescas, John Fedorovich and Nick De Firmian.
After the lost match, Kasparov said that he sometimes saw deep intelligence and creativity in the machine's moves, which he could not understand. He also suggested that humans may have helped the machine during the match. He demanded a rematch, but IBM declined and retired Deep Blue.
In part these allegations were correct. The rules provided for the engineers to modify the program between games, an opportunity they took with abandon. The code was modified between games to understand Kasparov's play style better, allowing it to avoid a trap in the final game that the AI had fallen for twice before. Feng-Hsiung Hsu later claimed in his book Behind Deep Blue: Building the Computer that Defeated the World Chess Champion that he had the rights to use the Deep Blue design to build a bigger machine independently of IBM to take Kasparov's rematch offer, but Kasparov refused to agree to a rematch (see also Hsu's open letter about the rematch linked below). Kasparov's defeat to Deep Blue has inspired the creation of a new game called 'Arimaa' which is still played with a standard chess set, but is much more difficult for computers.
