The first computer to beat a human chess master. In 1996, IBM's Deep Blue beat Garry Kasparov in game one of a six-game match and won the entire rematch a year later.
From ChipTest to Deep Thought to Deep Blue
Deep Blue originated as the ChipTest chess-playing computer at Carnegie Mellon University in the mid-1980s. Evolving into Deep Thought under IBM's direction, it won the North American and World Class Chess Championships in the late 1980s.
Specialized for Chess
Deep Blue was based on a 30-node RS/6000 parallel computer running AIX (IBM's Unix). With each node augmented by 480 chips specialized for the game, Deep Blue could evaluate up to 20 chess moves ahead. See RS/6000