The Longest Tournament Chess Game

The longest tournament chess game (in terms of moves) ever to be played was Nikolić–Arsović, Belgrade 1989, which lasted for 269 moves and took 20 hours and 15 minutes to complete a drawn game. At the time this game was played, FIDE had modified the fifty-move rule to allow 100 moves to be played without a piece being captured in a rook and bishop versus rook endgame, the situation in Nikolić versus Arsović. FIDE has since rescinded that modification to the rule.