A chosen card is signed and lost in the deck.
In one gesture, the magician vanishes all the faces of the cards...from now all the face of the cards are completely blanks! And the chosen card has vanish as well...
The magician removes a card case from his pocket (the card case could have been on the table in full view from the beginning). Due to the fact that the top of the card case is transparent, the spectator can clearly see it is completely empty.
The card case is put on the mat to prevent any sleight of hands.
With a simple pinch on the card case, the selected card instantly appears in the box.
The spectator removes himself his card from the boxe with the signature on it. Everything is totally examinable!