Garry Kasparov is a Russian Grandmaster who is coming out of retirement for the Saint Louis Rapid and Blitz tournament. Kasparov became the youngest ever undisputed World Chess Champion in 1985 at age 22 by defeating then-champion Anatoly Karpov. As world champion, he was known for his aggressive attacking style. In 1996 and 1997, Kasparov played the IBM supercomputer, Deep Blue, in a series of highly publicized matches. From 1986 until his retirement in 2005, Kasparov was ranked World No. 1 and is considered by many to be the greatest chess player in history.