Claim: Garry Kasparov won his first major chess tournament on April 13, 1963.
Evidence: Garry Kimovich Kasparov -LRB- Га́рри Ки́мович Каспа́ров , -LSB- ˈɡarʲɪ ˈkʲiməvʲɪtɕ kɐˈsparəf -RSB- ; born Garik Kimovich Weinstein , 13 April 1963 -RRB- is a Russian chess grandmaster , former World Chess Champion , writer , and political activist , whom many consider to be the greatest chess player of all time.