The Twenty One Card Trick is a trick illusion effect where the conjurer deals twenty one playing cards onto the table, and into 3 card value face up piles of 7 cards each, & asks the observer to try to remember any of the cards viewed. The viewer is not supposed to tell the magician which card is being thought of, but advises the conjurer which stack the card is in. This is executed three times & the conjurer is able to tell the spectator which card they had in mind. The cards are doled out into the piles one after another, like when dealing out hands in a playing card game. Every time they are dealt, after the observer indicates which stack contains the thought of playing card, the illusionist places that pile between the other two. After the first time, the playing card will be one of the ones in positions 8 to 14. When the cards are dealt the second time, the choice will be the third, 4th, or fifth playing card in the stack it finds itself. In picking up the stacks, the conjurer places this stack between the other two again. This guarantees that the choice will now be one of those in position ten to twelve. The third occasion the playing cards are dealt out, the choice will be the fourth playing card in which ever pile it ends up in. On the third deal, as soon as the spectator points out which stack contains the choice, the magician knows that it is the 4th, or centre, playing card in that stack. If the magician collects up the piles again, as before with the pile comprising the selection in the middle, the choice will be the eleventh card in the 21 playing card packet.