Development of the World Chess Championship became the first unified and undisputed World Chess Champion since Kasparov split from FIDE to form the PCA in 1993. Kramnik played to defend his title at the World Chess Championship 2007 in Mexico. This was an 8-player double round robin tournament, the same format as was used for the FIDE World Chess Championship 2005. This tournament was won by Viswanathan Anand. Because Anand's World Chess Champion title was won in a tournament rather than a match, a minority of commentators questioned the validity of his title. Kramnik also made ambiguous comments about the value of Anand's title, but did
World Chess Championship the winner playing a match against the champion for the title. These have followed a 2-year cycle: qualification for the Candidates in the odd year, the Candidates tournament early in the even year, and World Championship match late in the even year. Magnus Carlsen defeated Anand in the World Chess Championship 2013. Carlsen has successfully defended his title thrice, against Anand in the World Chess Championship 2014, against Sergey Karjakin in the World Chess Championship 2016, and against Fabiano Caruana in the World Chess Championship 2018. His last two defences were decided by tie-break in rapid games. Before 1948 world