There was constant controversy off the board, with X-raying of chairs, protests about the flags used on the board, hypnotism complaints and the mirror glasses used by Korchnoi. When Karpov's team sent him a blueberry yogurt during a game without any request for one by Karpov, the Korchnoi team protested, claiming it could be some kind of code. They later said this was intended as a parody of earlier protests, but it was taken seriously at the time. The story of these off-the-board struggles has been reported in detail, from the Korchnoi point of view.