This is a very fine trick that just works as advertised. Even though I collect tricks like this one,
the principle was new to me. It is very easy to perform, the method is well hidden. When explained
you might think that this won't work, so you can fool yourself.
Thomas mentioned that the
spectator can shuffle the deck beforehand, which is not true without a special handling that is not
explained. But that is a minor detail.
If you don't use a joker, btw, the correct number
for a deck of 52 cards is 29. A tipp: show cards from the bottom of the deck, this will speed things
up a bit.
The other thing is: Thomas mentions that you can look down the blindfold, but
that is rather unnecessary. You can be genuinely blindfolded, there is no need to see anything, if
your spectator handles everything the way you tell him. The instructions are easy to follow. The
only skill needed is spectator management, don't do it with someone who does not follow your
instructions.