MOSCOW (AP) _ Garry Kasparov, the brilliant and aggressive tactician regarded by many as the greatest chess player of all time, announced his retirement from professional play. He said he plans to write books and become more active in the politics of Russia, a country that's ``headed down the wrong path.''
The 41-year-old Kasparov has been ranked No. 1 in the world since 1984, dominating chess for two decades with formidable energy, discipline and intellect. His announcement came shortly after he won the 14-match Linares tournament in Spain.
Kasparov's mastery of chess seemed sometimes to be superhuman, and perhaps his most famous loss was a 1997 match against IBM supercomputer Deep Blue.
Shay Bushinsky, a programmer behind another chess computer, told The Associated Press that as a chess player Kasparov was ``the closest thing to a computer that I know as a man. Sometimes I think he has silicon running in his veins.''
But Kasparov also became famous for his colorful and vibrant personality. He was seen as an especially vital and well-rounded person in a pursuit where top players often have the image of not having interests besides chess.
``He isn't just a pawn; and he isn't just a database, either, an inflated cerebellum, a throbbing maniac in the closed system of 64 squares,'' novelist Martin Amis wrote of him in a 1993 essay.
Among Kasparov's interests is politics. A Russian citizen, Kasparov has emerged as an outspoken critic of President Vladimir Putin and is playing a leading role in the Committee 2008: Free Choice, a group formed by liberal opposition leaders.
But he was increasingly exasperated with the politics of the chess world, which has been bitterly divided since 1993 into two rival federations with rival champions. In his retirement announcement Thursday, he reiterated that he was disappointed with a failed campaign to reunify the title.
He also said part of the reason he was retiring was that he saw no real goals in professional chess.
``As a chess player, I did everything I could, even more. Now I want to use my intellect and strategic thinking in Russian politics,'' Kasparov said Friday in a statement cited by the Interfax news agency.
``I will do everything in my power to resist Putin's dictatorship,'' he said. ``My opinion is that the country is headed down the wrong path now.''
Kasparov said he would continue to play chess, write books about it and take part in tournaments, such as events in which he plays many opponents at once, or in speed-chess games.
Alexander Roshal, chief editor of a popular Russian chess magazine called 64, said Kasparov had no peers in the chess world.
``There's no one else of his caliber. No one comes close. He saw that, and said 'you go on without me,''' he said.
Kasparov evidently was thinking about retiring for a long time after it became clear the reunification title match would not happen soon, Roshal said.
``He won more than 40 super-tournaments and in a month he'll be 42,'' Roshal said. ``For chess, that's not young, and he has no reason to waste time preparing for another tournament. He's not going to be greater than he was or is.''
Born in Baku in the then-Soviet republic of Azerbaijan, Kasparov is thought by many to be the best chess player in history. His defeat by Deep Blue was seen as a watershed moment in technological advancement, but in 2003 he averted a similar defeat when he agreed to a draw in the last game of his series against Deep Junior, which could process 3 million chess moves per second.
``Kasparov has the most incredible look-ahead and memory capabilities I have ever seen,'' said Bushinsky, one of two Israelis who helped design Deep Junior.
Kasparov's chess talent was apparent at an early age. At 12 he became the youngest player ever to win the USSR Junior Championship. Four years later, he won the World Junior Championship, and achieved the title of grandmaster on his 17th birthday.
His first title match, from September 1984 to February 1985 against Anatoly Karpov, was the longest in chess history. After 48 games, the psychological and physical strain on Karpov, who was leading but appeared likely to lose, caused chess authorities to end the match inconclusively amid controversy.
Kasparov won a rematch six months later, becoming the youngest world champion ever. He defended his title against Karpov in 1986, 1987 and 1990.