Deep Blue (chess computer) offer, but Kasparov refused a rematch. Deep Blue, with its capability of evaluating 200 million positions per second, was the fastest computer to face a world chess champion. Today, in computer chess research and matches of world class players against computers, the focus of play has often shifted to software , rather than using dedicated chess hardware. Modern chess programs like Houdini, Rybka, Deep Fritz or Deep Junior are more efficient than the programs during Deep Blue's era. In a November 2006 match between Deep Fritz and world chess champion Vladimir Kramnik, the program ran on a computer system containing
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