The Classical World Chess Championship 2004 was held from September 25, 2004, to October 18, 2004, in Brissago, Switzerland. Vladimir Kramnik, the defending champion, played Peter Leko, the challenger, in a fourteen-game match.
The match ended 7–7, each player scoring two wins. Kramnik retained his title under the rules of the match.
Classical World Chess Championship 2004 Wikipedia
Garry Kasparov's split from FIDE in 1993 resulted in two lines of world chess champions. There was the 'Classical' world champion, the title that only passes on to a player when he beats the previous world champion. This was held by Kasparov, until he was defeated by Kramnik in the Classical World Chess Championship 2000. There was also the "Official" FIDE world champion who, at the time of this match, was Rustam Kasimdzhanov.
The split World Champion title led to calls for a reunification. After negotiations all parties agreed to the "Prague Agreement", wherein the winner of this match (the "Classical" World Champion) would play the winner of a match between Kasparov and the FIDE World Champion, and the winner would be the World Champion. These other matches never took place, but the titles were later unified at the FIDE World Chess Championship 2006.
The 2002 Dortmund Sparkassen Chess Meeting acted as the Candidates Tournament to determine the challenger to Kramnik's title. However, not all of the top-ranked players were present. World No. 1 Garry Kasparov declined his invitation, instead insisting that he deserved a rematch with Kramnik based on his tournament results in 2001. Some other players, including world No. 2 Viswanathan Anand, declined invitations because they believed they were in conflict with their obligations under the rival FIDE World Championship.
Leko won the Candidates Tournament:
Shirov won a two-game playoff 1½-½ to be placed first ahead of Topalov.
The top two from each group advanced to the knock-out stage where mini-matches (best of 4) were played, with a 2-game rapid chess playoff in the event of a tie.
Topalov–Bareev was tied 2–2; Topalov won the rapid playoff 1½–½.Game 1 – as black, Kramnik sacrifices his queen for rook and bishop, and outplays Leko in the ending to take the lead.
Game 5 – Leko, as white, goes into an ending a pawn up with some winning chances, and outplays Kramnik to win, and level the match.
Game 8 – Leko, as black in the Marshall Attack, plays into a line prepared by Kramnik's team, and finds the refutation over the board, to take a one-point lead. Chessbase wrote, "Many questions were answered by today's eighth match game. Does Leko have what it takes to beat Kramnik in a match? Is Kramnik's preparation simply unbeatable? Why don't many top players allow the Marshall Gambit with white? (That's 'yes', 'no', and 'because no matter how well prepared you are you may get killed'.)"
Game 12 – Leko switches to the Caro–Kann Defence. Kramnik has winning chances, but Leko defends well and, with both players short on time, Leko offers a draw on move 34.
Game 13 – Kramnik plays the Benoni, in a surprise attempt to win with black, but the game is drawn. Kramnik must now win the final game.
Game 14 – Kramnik wins the final game to tie the match and retain his title.