I am actually working on a trick where i find the spectator's chosen card face down ... But for me to do that i will need to mark the back of one card that i can easily see when they are face down. Can you please tell me where i should mark it and what should the mark be in order for it to be stealthy.. Btw , i'm using regular rider back cards.
Th4nk Y0u
Th4nk Y0u