Mid-Air Card Stab by John Kennedy Magic

Stab a chosen card in mid-air with a pocket knife! This improved version of John Kennedy's classic effect is the best ever. Why?
- Any brand of playing cards can be used
- The card is freely chosen. No force is used
- The card can be signed and then given out as a souvenir after you stab it
- You're always ready to perform. No reset is needed
- The knife looks innocent and can even be examined