Fooling Churchill
The magician Paul Curry created the following trick known as either “Out of This World” or “The Trick that Fooled Churchill” since it was supposedly performed for him during the war.
The Effect
The Magician holds a pack of cards and deals out one red and one black card face up side by side. These are the ‘header cards.’ He hands the deck to the Subject and asks him to deal the cards one at a time face down and try to intuit which cards are red and which black and put them face down under the corresponding face up header card. Half way through the deck the Magician takes back the cards, puts down two new header cards and asks the Subject to continue. The reason for this interruption might be something about eliminating left/right bias. When the Subject has finished the Magician picks up the groups of cards, turns them over and reveals that the Subject has somehow got every single card right!
This can be passed off as a pure magic trick or as a demonstration of Extra Sensory Perception, ESP.
The Method
The deck is set up initially so that all reds are in the top half and all blacks at the bottom. As the Subject randomly puts down the first half of the deck into two columns the Magician has to keep count so that he knows when the red cards end and the black begin. Leaving one red card for a new header, the Magician puts down a face up red, and a face up black card. (Obviously this should be done with some fiddling through the cards so that it looks like the Magician doesn’t himself know which are red and which black.) The Subject then continues with the division of the face down cards into the two piles. Now it’s just a matter of the Magician picking up the cards in a way that distracts the Subject from the fact that the he is swapping piles over.
It is possible for the Subject to place the cards as if they are all red or all black. This would clearly mess up the Effect and so requires some handling by the Magician. The Magician can also intervene a few times, as a gag, to say “Just a second, I think that one is wrong. Do you mind if I move it to the other column? But I think generally you’re doing great!”