Viktor Lvovich Korchnoi ( Russian : Ви́ктор Льво́вич Корчно́й , IPA : ( kɐrt͡ɕˈnoj ) ; born 23 March 1931 ) is a professional chess player , author and until recently the oldest active grandmaster on the tournament circuit .
He is a professional chess player , author and is now the oldest active grandmaster on the regular tournament circuit .