Shuffle tracking is an advantage gambling technique where a player tracks certain cards or sequences of cards through a series of shuffles. Shuffle tracking is typically done in blackjack games, although it can be done in other card games. Games with simple shuffles are generally easier to shuffle track than games with complicated shuffles. Thus, shuffle tracking is usually done in 6 or 8 deck shoe-dealt blackjack games, as these tend to have simpler shuffles compared to pitch games, due to the time required to accomplish a complicated shuffle on 6 or 8 decks of cards.
Shuffle tracking is an advanced technique used with card counting. Many types of shuffle tracking exist. Generally, the player, or a team member, keeps track of the count (high cards versus low cards) of one or more subsections of the cards as they are played. The selected sections may or may not be predetermined by observing and mapping the shuffle. These sections are referred to as tracking zones. The player may attempt to follow slugs of cards through the shuffle, or have a good idea of the final location by previously analyzing the shuffle. After the shuffle, play zones exist which contain most of the cards in the tracking zone as well as other cards. The player can then cut zones with high cards into play, or with low cards out of play, thus changing the normal composition of the shoe. Betting can then be altered to reflect the altered composition.
Another form related to shuffle tracking is called ace sequencing, because it involves attempting to determine when an ace is about to be dealt. If a player knows that he will be dealt an ace as his first card, he gains a 50.43% advantage. This is because a player has about a 31% (depending on number of decks) chance of getting a blackjack and a good chance of making a strong hand if he is not dealt a blackjack. First the player should know what segments the discards are likely to appear relatively intact after a shuffle. He then observes aces as they are placed into the discard tray within a segment. He then remembers the two or three cards placed on top of the ace in the tray. These are called key cards. After the shuffle, the player looks for the key cards. The ace is likely to follow these cards and the player may be able to raise his bet in anticipation of receiving the ace.