World Chess Championship a Kasparov match, either with 2002 FIDE champion Ponomariov, or 2004 FIDE champion Kasimdzhanov. Partly due to his frustration at the situation, Kasparov retired from chess in 2005, still ranked No. 1 in the world. Soon after, FIDE dropped the short knockout format for a World Championship and announced the FIDE World Chess Championship 2005, a double round robin tournament to be held in San Luis, Argentina between eight of the leading players in the world. However Kramnik insisted that his title be decided in a match, and declined to participate. The tournament was convincingly won by the Bulgarian Veselin
World Chess Championship 2007 match. The FIDE World Chess Championship 2005 was also a double round robin tournament, but at the time the world title was split, with that tournament being for the FIDE world championship, and with Classical World Champion Vladimir Kramnik refusing to take part. Soon after the 2005 tournament, FIDE announced that the 2007 World Championship would also be a double round robin tournament. In 2006, FIDE announced the World Chess Championship 2006, to reunify the world chess championship. Because the organization of the 2007 tournament was largely in place, conditions of that match included: Kramnik won the 2006 match. In