How is shuffle tracking done?
First, the shuffle tracking expert in blackjack performs card counting during play. This tells him or her what cards are in the discard tray and what were left unplayed by the time the next shuffle comes. Next, the shuffle tracking expert watches how a dealer shuffles the cards. A blackjack dealer will cut the deck(s) into different parts, riffle them and re-stack them together. Once the expert in shuffle tracking knows the method, he or she simulates the shuffle with his or her own chips which symbolically represent the different parts of the deck(s). At the end of the shuffle, the shuffle tracker has a good idea where the needed cards are.
