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The Lie Detector: Magic Tutorial

This is a wonderful trick. It was shown to me by Bob Ostin in the 1970s. Bob was a kind and inventive fellow who became something of a mentor. He had a lot of experience as a professional entertainer, having worked on club, cabaret, and kids' shows earlier in his life but, when I knew him, he was a modest and enthusiastic amateur who always had some magical novelty to show. A simple method and an entertaining premise were hallmarks of his work.
Bob learned The Lie Detector trick from his pal Harry Ivanov. They were both members of the Mahatma Circle of Magicians in Liverpool and, together, they marketed another version of The Lie Detector via Ken Brooke. That version used punched cards. But the version here uses a regular deck and features a bit of business by Bob that really sells the effect.
Plot
A card is selected and lost in the deck. The spectator is invited to lie or tell the truth as the performer asks several questions about the identity of the chosen card. Each answer is spelled from the deck, one card at a time. The answers always lead to the selection.
Method
The selected card is controlled to the 20th position from the top of the deck. No matter how the spectator answers your questions, you will always be able to spell and deal to the selection. Those are the bare bones, but it’s the presentation that makes it such a good item.
Presentation
Secretly set a crimped card 20th from the bottom of the deck. An easy way to do this is to spread the cards with their faces toward you as you look for the Jokers. Upjog each Joker as you count 20 cards from the face of the deck. Crimp the lower-left corner of the 20th card with your left thumb (Figure 1). Remove the Jokers and place them aside, saying, “We don’t need these,” and you are all set. The crimped end of the deck should be toward you during the performance.

Figure 1
Incidentally, you don’t need to count cards one at a time as you spread the deck. Push them over in batches of four, counting a number for each batch. When you reach the count of 5 (x5 batches of 4), you are at the 20th card.
Setting up the Premise
Choose a spectator and ask if they can help, saying that you chose them because they have a very honest face. And when they’ve smiled at your praise add, “The kind of face that could hide a lie. Don’t worry, it’s a good thing to have. Let me show you.”
Controlling the Selection
Spread the deck face down between your hands and have a card selected from the upper portion. Square the deck and, as the spectator looks at and remembers the card, swing cut the upper half into your left hand (Figure 2). Have the spectator replace the memorized card on top of the left-hand portion. Drop the right-hand packet on top and place the deck on the table.

Figure 2
Immediately, give the deck a couple of cuts to lose the selection. Ask the spectator to do the same. Pick up the deck and give it one final cut, but this time at the crimp. The crimp will go to the bottom of the deck. The selection is now 20 cards from the top. Occasionally, you will find that the spectator cuts the crimped card to the bottom. Lucky you.
Spread the deck face down across the table and ask the spectator, “Do you have any idea where your card is?”
Usually, they’ll say no. If they say it’s at the bottom or the top, you can show them that it isn’t. The reason you ask this question is that the end of the trick proves that, somehow, they seemed to know exactly where their card was.
Questions & Answers
Gather up the deck, saying, “I’m going to ask you some simple questions. And you can lie or tell the truth. The choice is yours. First question: was your card red or black?”
Let’s assume that they say ‘Black.’ Spell the word ‘black’ aloud, dealing one card for each letter face down onto the table. Do it quickly and toss the cards onto the table so they form a messy pile.
“Second question. You said your card was black. Was it a Club or a Spade? You can lie or tell the truth.” The spectator says, “Spade,” and you spell and deal a card for each letter. When you finish, say, “The observant among you will notice that if she lied on the first answer, that lie is now compounded by a second. Oh, what a tangled web of lies you are weaving.”
“Let’s give you another chance to lie or tell the truth. Was your card a court card or did it have spots?” You spell out the answer, dealing more cards to the table.
“Finally—and I want you to answer this question honestly, are you ready—have you been telling lies or telling the truth?”
Now, this is where Bob Ostin had a nice twist. After a brief pause, you add, “Or maybe it was a bit of both?”
What you’re trying to do is give the spectator the opportunity of admitting they lied on some questions and told the truth on others. If they do this, you immediately say, “Okay both.” And you spell B-O-T-H as you deal four more cards to the table. Bob always got a laugh with this. It seems improvised and adds a devil-may-care attitude to the proceedings.
Time to recap and explain what’s happening in terms of the method. So far, you have spelled BLACK, SPADE, COURT, and BOTH. That’s 19 cards. The chosen card is the 20th. Take the next card, put the deck aside, and say, “I asked at the beginning if you knew where your card was. And you said ‘No.’ But I also said you’d make a good liar. What was your card?” The spectator names her card and you turn it over to show she’s found it.
How to Spell
It doesn’t matter what answers the spectator gives; you can always contrive to deal down to the 20th card. In our example, you dealt off 19 cards and turned over the 20. In other cases, you will deal down 20 cards and turn over the 20th card. I’ve tweaked the spellings from Bob and Harry’s original to make things simpler and outlined them in the flow chart below.

You'll see that a major difference in spelling comes when the spectator says CLUB, which you spell as CLUBS. And when the spectator says HEARTS. When this happens you ask if the card was a NUMBER or PICTURE, instead of SPOTS or COURT. When this stage is completed, no matter which answers were given, you have dealt off 15 cards. The answer to the last question will either spell with 4 or 5 letters which tells you whether to show the last card spelled or the next one as the selection. You can, of course, adjust the spellings to your preference.
Notes
Good tricks have simple plots and stories that are easily understood. The light-hearted premise here is that one of the spectators is an excellent liar. The finale of the trick delivers upon the premise. The story feels complete.
If you can make the spectator apparently responsible for the success of a trick, that can be better than taking the credit yourself. It makes the performance feel more like a community effort and less like shamelessly showing off.
Whenever you do a find-a-card trick, make sure the spectator remembers their selection. You can even ask them to show it to the people next to them. This is especially true in a trick where you are inviting the spectator to lie. You never know when you might need an honest witness.
Finally, if you need to secretly set a crimp or even stack a few cards, think about doing it in an earlier trick. For example, you might remove four aces to perform Twisting the Aces or Dr. Daley’s Last Trick. Removing the aces is a good opportunity to set the deck for the next trick. That’s truly working ‘One Ahead.’
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