During the World Championship qualifier of 1959, grandmaster Pal Benko wore dark glasses to counter the hypnotic gaze of his dangerous opponent, world champion-to-be Mikhail Tal. This precaution did him no good (see this week’s puzzle).
 
This is not the only instance when hypnosis has been suspected in chess. In the 1978 world championship, Viktor Korchnoi accused Anatoly Karpov’s assistant, Dr Vladimir Zukhar, of disrupting his thought processes by attacking him telepathically.