The Last Card Wizard is a card trick where the player secretly picks a number between one and ten, uses it to select a starting card, and then "chains" through the deck, from link to link to a final link. The player continues tapping cards through the actual last card so as to not give away the last link card. (Of course, occasionally the actual last card might be the last link but this is unusual.) When all of the cards are turned up and the actual last card is tapped, the wizard program highlights the last link card in yellow.
Chaining through the deck is done like this. The player begins by tapping the first card and each consecutive card through the last 52nd card of the deck. But while tapping the player first counts to their secret number and silently note the card at that location. That card is the first link card. It's value determines the number of cards to count to get to the next link card. The counting begins with the card to the immediate right of the link card.
The value of the card is it normal value except that an ace must be counted as one and the picture cards, Jack, Queen, and King, must be counted as five.
The prediction method was developed by Martin D. Kruskal , a mathematician and physicist who lived from 1925 to 2006. In Kruskal's prediction of the last link card is usually correct but not always. The Last Card Wizard's prediction of the last link card will always be correct without exception.
Many explanations of how the Kruskal mode works are available on the web, including YouTube demos with real playing cards. Just search on "The Kruskal Count". There is a particularly good write-up by Ivars Peterson at www.maa.org/mathland/mathtrek_12_24_01.html
. There is a formal mathematically paper on the subject at www.arxiv.org/abs/math/0110143
Martin D. Kruskal, 1925 - 2006
The Kruskal Count and the Last Card card trick were popularized by Martin Gardner in his Scientific American column, Mathematical Recreations.
Martin Gardner, 1914 - 2010
Uri Geller performed the Last Card trick with real cards on the Johnny Carson Tonight Show sometime around 1975. He failed to get the last card correctly. Merv Griffin declared that the failure proved to him that Geller's powers were genuine. Magician's tricks, Griffin explained always work. We all know how the "force" comes and goes.
Johnny Carson, 1925 - 2005,
Carnac , the Magnificent
The following are screen-shots from the Last Card Wizard app.
Initially the cards appear face-down in four rows of 13 cards each. Then they are flipped over, revealing that all of the cards are there, and in order.
The app waits for the play to click on "Shuffle?". The cards are shuffled by starting at the beginning of the first row and card-by-card making an exchange with a randomly selected other card.
When all of the cards have been shuffled, a pale blue film is put on them and the player can do their count through the deal. Each card must be counted. When a card is count the blue film is removed, card-by-card. This is to help the counter keep track of where they are.
If the player looses count they can click on the "Recount?" button and start over. When the player clicks on all of the cards, the Last Card Wizard announces the players last card in the chain of links based on their original secret number between 1 and 10.
The Last Card is highlighted in yellow and the center button label says "Solved!". If the play thinks the Wizard got it wrong, they are advised to select Recount?. After a few seconds the "Solved!" is replaced by "Shuffle?" and the player can have another go at it with a new shuffle.
To watch a 8:52 minute YouTube video, click this link: Last Card