Chess tournament

A chess tournament is a competition between chess players. It can take one of these forms:
Since the first international chess tournament in London, 1851, chess tournaments have become the standard form of chess competition among serious players. Currently, FIDE holds candidates tournaments every two years to determine challenger to the world champion.
In 1851, Adolf Anderssen became first unofficial champion. In 1858, Paul Morphy beat him and became second unofficial champion. In 1871, Johannez Zukertort defeated Adolf Anderssen to become third unofficial chess champion. There are three unofficial world chess champions: Adolf Anderssen, Paul Morphy and Johannes Zukertort, stemming from first strong international tournament in London in 1851, won by Anderssen.