The Stack:
* The deck is arranged with alternating "forcing" and "dummy" cards. The forcing cards are the ones the performer wants to appear, while the dummies are filler cards.
* All the forcing cards are identical. For example, all the "forcing" cards could be the Ace of Spades.
* The dummy cards are all different. They're shuffled randomly, so the audience doesn't realize they're not actually playing with a standard deck.
How it Works:
1. The performer deals the cards face down. Because of the stack, every other card is a forcing card.
2. The audience chooses a card. They're essentially choosing between the dummy and the forcing cards, but the performer makes sure they don't see the forcing card.
3. The performer "predicts" the chosen card. They've already stacked the deck to force a specific card. Since the forcing cards are all identical, the performer "knows" the chosen card.
Example:
Imagine a Svengali deck with the Ace of Spades as the forcing card. When a spectator chooses a card, they will either pick a dummy card or the Ace of Spades. Regardless, the performer can "predict" the chosen card as the Ace of Spades because the deck is stacked to ensure that happens.
Key Points:
* It's not magic: It relies on the pre-arranged stack, not on any tricks or sleight of hand.
* It's not random: The audience only has the illusion of choice. The outcome is predetermined.
* It's a simple but effective trick: It can be used to create surprising results in card tricks and other performances.
Beyond the Svengali:
There are other types of stacked decks, each with different tricks and effects. However, the Svengali deck remains one of the most popular and versatile tools for card magicians.