Note: For those who own the original Rain Man, you're in for a real treat (see the last condition in the conditions section below).
Imagine:
The magician and the spectator are seated together at a table. The magician introduces a deck of cards and spreads it face up to show that all the cards are different. After this, he turns his back to the spectator and says "I want you to generate a random number between 1 and 52. Of course, I could have you name one, but then you may think I psychologically influenced you towards a particular number or that I relied on you to think of a popular number. So to eliminate such ideas, I want you to generate a number by cutting off any amount of cards from the top of the deck and then secretly counting how many you cut off. If you'd like, count the cut off amount under the table silently." The spectator does this (the magician is turned away the entire time; he doesn't look back even once).
Next, the magician (while still turned away) tells the spectator to bury the cut-off portion somewhere into the middle of the remaining portion so that there is no evidence left as to the number of cards they cut off. They do that. With that done, the magician (while still turned away) asks them to give the deck as many complete cuts as they want, followed by as many riffle shuffles as they want. They do all that. As they're doing that, the magician explains that it's mathematically proven that it takes 7 riffle shuffles to truly randomize the order of a deck. So the spectator could give the deck 7 riffle shuffles (if they want).
It is only at this point that the magician turns back around to face the spectator. He briefly recaps what happened and then takes the deck from them (the first time that he's touching it ever since he gave it to them at the very beginning) and spreads through its faces towards himself in order to memorize it (without disturbing its order). Alternatively, he could deal through the shuffled deck face up whilst attempting to memorize it. Once he's done that, he hands the deck back to the spectator in a squared, face down position (and still in the very order in which they shuffled it). The spectator is then, for the first time, asked to name their randomly generated number. And, at that point, after a brief moment of thinking, the magician tells them the card at that number and some of the surrounding cards as well. The spectator counts down themself to check if the magician's memory is correct ... and indeed it is.
Some important conditions of note:
- When generating the random number, the spectator has a completely free choice as to where to cut the deck. There isn't anything to force the point at which they cut.
- While the spectator is secretly counting the number of cards they cut off, the magician doesn't peek behind him to look at the remaining portion of cards in order to visually estimate from those the number of cards the spectator cut off. The magician only turns back around after the spectator has reassembled and shuffled the entire deck.
- The magician only touches the deck for the first time (since the beginning) after the spectator is finished shuffling it.
- The method for this is completely different compared to the method of Rain Man. The deck is not marked.
1st edition 2023, PDF 13 pages.