Advanced Chess man and machine." The concept of computer-assisted chess tournaments originated in science fiction, notably in "The Peace War" written by Vernor Vinge in 1984. The former world champion grandmaster Garry Kasparov, who retired from competitive chess in 2005, has a long history in playing "Man vs. Machine" events. Among the most important are his matches against IBM's computer Deep Blue, which Kasparov defeated in February 1996, scoring 4–2 in a 6-game match, and lost to, –, in a May 1997 rematch. This 1997 match was famous, as it was the first time in the history of chess in which a
Reversi game has been particularly attractive to programmers. Therefore, the best Othello computer programs have easily defeated the best humans since 1980, when the program "The Moor" beat the reigning world champion. In 1997, Logistello defeated the human champion Takeshi Murakami with a score of 6–0. Analysts have estimated the number of legal positions in Othello is at most 10, and it has a game-tree complexity of approximately 10. Mathematically, Othello still remains unsolved. Experts have not absolutely resolved what the outcome of a game will be where both sides use perfect play. However, analysis of thousands of high quality games