This is a very good intermediate level effect. Basically, the spectator chooses a card, you attempt
to find it... you choose the wrong card, but then it changes to the selected card... and then you
reveal that their selection was the only odd-backed card in the entire deck, even though they've
(apparently) been seeing the backs of the full deck during the entire routine.
During the
course of the explanation, you'll have quite a few sleights explained in adequate detail... riffle
force, slip cuts, acquiring breaks, the shake change, classic pass... there's an impressive amount
of material packed into a short amount of time.
If you're already handy with a deck of
cards, this is a really nice routine to play around with. If you're a beginner, this is a good
introduction to more advanced handlings, since you'll end up with good instruction on a solid bunch
of useful moves.