Hiviki - Wonder Business Card

A very clean mental magic effect that uses business cards.
Effect:
The magician introduces and spreads 5 blank business cards on the table.
While the magician's back is turned the spectator signs 1 of the cards, and flips it over.
The spectator will then gather and shuffle the cards and hand it back to the magician.
The magician will spread the cards again and accurately find the signed card.
No marks, no magnets, no devices.
100% accurate.
The magician can sign the back of the card and hand it out as a souvenir.
- Both sides of the business cards are blank
- No pencil dots, no crimps, no marks
- Your hands are always empty
- Everything is examinable
- Free choice, no forces
- The magician can sign the card and hand it out as a souvenir
- No resets, repeatable