Two accomplices are required. Each, however, supposes that he alone is
in the secret. To the first accomplice, for instance, you say that the
card to be noted is the king of hearts. You take this card from the
pack, and give it to the second accomplice to hide somewhere. You then
shuffle the cards, let Accomplice A shuffle them also, and then begin a
conversation like the following:
You say to Accomplice A, “Kindly note a card in this pack. Shuffle the
cards again, and then tell me the name of the card you noted. The king
of hearts, is it? Thank you for the king of hearts.”
“But I cannot find that card.”
“Was it really the king of hearts that you noted?”
“Certainly.”
“Ah, I see how it is. His Majesty has gone out for a stroll. Perhaps,
sir,” addressing Accomplice No. 2. “you saw which road the runaway
went.”
“I rather fancy I saw him hide behind the clock.”
“Will one of you be so good as to look behind the clock?”
And to the general astonishment the missing card is actually found
behind the clock, or where else it was placed.