This trick, which calls upon something known as the “key card principle,” is easy enough to learn in five minutes and, as Dave notes, is sure to “sway things in your favor whether you’re betting for the next round of beers, or looking for a raise.”
“Knowing the location of a single card in a deck offers a huge advantage for games like poker and blackjack. It’s fairly easy to catch glimpse the bottom card of the deck while a dealer is shuffling, but there’s always the cut, which spoils it. Luckily, there’s a way around that. Let’s say the bottom card before the cut is an Ace. To ascertain its whereabouts, just estimate the number of cards cut. If the cut was near the center, and if five of you are playing five-card draw, then you know that that Ace will be one of the last cards dealt, or first cards drawn. Magicians also utilize knowledge of a single card. In their craft, it’s known as the ‘key card principle.’ But for magicians it’s a lot simpler than tracking and estimating the location of the card.”
“Have someone shuffle the deck. If the cards are shuffled in a way that allows you to see the bottom card, then you’re all set. Let’s say the bottom card is the six of clubs. Ask the subject to hold the deck face down in her hand. Have her remove any card from the center of the deck without showing it to you. Have her remember the card and place it face down on top of the deck. Then have her cut the deck. She can even cut it twice. With your ‘key card’—the six of clubs—the card she chose can be found easily. Take the cards back and spread them face up. Her card will be directly above the six of clubs.”
“Begin dealing the cards face up off the top of the deck. Do it slowly and deliberately to build suspense. Once you deal the six of clubs, the next card dealt will be the selected card. Don’t pause. Just continue dealing more cards face up. After dealing several more, stop and announce, ‘The next card I turn over will be yours.’ At this point, everyone will assume you have failed, because they saw you pass right over the selected card. They might even be willing to bet on it. Whatever the case, once all bets are placed, the next card you turn over is not the next card off the top of the deck, it’s the selected card previously dealt after the six of clubs, which you should turn face down.”
Want more from Dan & Dave? As you might guess, we’re big fans of their “Sleight of Hand Lotion” and we’ve watched this video of Dan and Dave showing off their chops on Icelandic television about a dozen times.