The Mystery of Magic’s Greatest Card Trick

At 94, the magician David Berglas says his renowned effect can’t be taught. Is he telling the truth?

LONDON — In the late 1940s, the British magician David Berglas started refining a trick that came to be known as “the holy grail of card magic.” To this day, nobody is certain how he did it. Decades into his retirement, he has revealed just about every secret in his long and storied career. This includes the time, in 1954, that he made a grand piano vanish in a London hotel banquet room filled with guests. (Distracted, the audience turned their focus in time to see a pianist, who seemed to be playing the instrument a moment earlier, fall facedown to the floor). But even now, when the subject of Mr. Berglas’s famous effect is raised, he remains as cryptic as ever. “It’s not a secret I can give to anyone because it’s not a secret as such,” said Mr. Berglas, a formal and intense 94-year-old, at his home in North London. “It’s like asking a musician who can improvise to teach you his improvisation, which of course he can’t.”