Notes on the World Championship 'Return Match'

From Predecessors II (p.215, on Botvinnik):

In 1956, soon after Smyslov's second victory in the Candidates tournament, an event occurred that was to have a strong influence on the entire modern history of chess: FIDE granted the World Champion the right to a return match [Kasparov's italics]. This decision was adopted together with the aforementioned 'Botvinnik rule' [a limit in the Candidates tournament on the number of participants from one country; p.186 & p.214], and also not without the participation of Botvinnik (his friend Ragozin was a FIDE Vice President). Although earlier, in the late 1940s, in his plan for the contesting of the World Championship, he had rejected the idea of the return match, since 'its organization would disturb the periodicity of the system, and in the interest of chess this must not be allowed', and he had gained the right for a defeated champion to play a match-tournament with the champion and the challenger three years later (this FIDE rule operated in the 1951 and 1954 matches).

From Predecessors II (p.336, on Smyslov):

In the 1956 FIDE Congress, the exotic right of an ex-champion to join as a third player in a match of the next cycle was replaced by the right of a return match. The FIDE President Folke Rogard was generally opposed to match-tournaments, fearing agreements between participants.

FIDE abolished the right of the return match before Botvinnik lost his 1963 match to Petrosian. It is curious that it was invoked in both of the World Championship cycles (1955-1957 and 1958-1960) where it was in effect. • Note also that FIDE's fiddling with rules on a cycle in progress is not exclusive to the Ilyumzhinov administration.