Garry Kimovich Kasparov is a Russian chess grandmaster, former World Chess Champion, writer, political activist and commentator. From 1984 until his retirement in 2005, Kasparov was ranked world No. 1 for a record 255 months overall for his career. His peak rating of 2851, achieved in 1999, was the highest recorded until being surpassed by Magnus Carlsen in 2013. Kasparov also holds records for the most consecutive professional tournament victories and Chess Oscars.
Kasparov became the youngest ever undisputed World Chess Champion in 1985 at age 22 by defeating then-champion Anatoly Karpov. He held the official FIDE world title until 1993 when a dispute with FIDE led him to set up a rival organization, the Professional Chess Association. In 1997 he became the first world champion to lose a match to a computer under standard time controls when he lost to the IBM supercomputer Deep Blue in a highly publicized match. He continued to hold the "Classical" World Chess Championship until his defeat by Vladimir Kramnik in 2000. Despite losing the title, he continued winning tournaments and was the world's highest-rated player when he retired from professional chess in 2005.