Selective Shuffling

Much has been made of card counting in blackjack in recent years . Several movies and books have tackled the subject, for example, and it seems that public awareness of the technique is quite high. Because of this, casinos are doing everything they can to protect themselves against potential card counters, and one of these techniques is called selective shuffling.

How Does Card Counting Work?


Card counting works by paying attention to which cards are already in play, and calculating the odds of the next cards you will be dealt.

Card counting is a technique used by gamblers to establish when a deck contains more high-value cards – that is, a 10, jack, queen, king or ace – than lower. The reason that this knowledge is important is because these cards give the player a higher likelihood of hitting a natural blackjack, which pays out 3-2. In addition, because the dealer must hit on anything up to 16, it gives the house more chances to bust.

There are several techniques, though they all hinge on a similar theme. The card counter must pay attention to every card that is dealt to every player at the table. He will have assigned each card a value and must keep track of the running total as the game progresses. Hi-Lo, the most straight-forward system, gives every card between 2 and 6 a value of 1, while 7, 8 and 9 have a value of 0, and 10 through A are all minus 1.

As the count gets higher – indicating that fewer 10s and aces have been dealt and more 2s through 6s have come and gone – the statistical advantage begins to lean towards the player. Furthermore, if the player is aware of this advantage, he can use the information in his favor. He can make a more educated decision about when to hit or stand, and can also increase or decrease his bet based on the count.

Is Card Counting Illegal?

Technically, there is no law against card counting in the United States, though if the player uses an external counting device or a second person to assist in counting cards, it would no longer be legal. However, casinos – for obvious reasons – aren’t thrilled about having card counters in their midst, and will do their best to discourage or intimidate card counters.

For example, if a casino staff member suspects a player of counting cards, he may simply engage the player in conversation in order to break his concentration. Sometimes, a manager will assign a high speed dealer that makes counting cards more difficult. Casinos may also utilize scanners in the blackjack table that can keep track of the changes in the bets placed as related to the rise or fall of the count.

There are also techniques used to counteract card counters that involve shuffling the deck more often, thus leaving the player unable to keep a running total of the cards. This is called selective, or preferential, shuffling.

What is Selective Shuffling?

Simply put, selective shuffling allows the house to shuffle the cards more often than it normally would. Here are a couple different ways selective shuffling may be used.


Selective shuffling and the use of multiple decks is a common way to prevent card counters.

Frequent Shuffling

- This is the most simple and low-tech method of selective shuffling. The dealer simply shuffles the cards more often – sometimes every few hands. This prevents card counters from seeing enough cards in any given deck to give them a true statistical advantage. This can be done using cut cards, which are interspersed throughout the deck. When one of these cards comes up, it indicates to the dealer that he should shuffle after the current hand is over. While these are common in blackjack, a casino that is using selective shuffling may put the cut card higher up in the deck.

Shuffling After a Bet is Raised

- Though cut cards are an indication that the cards must be shuffled, dealers may also be allowed to shuffle at their discretion. Because of this, a dealer may reshuffle the cards when a player raises his bet, as this can be an indication that he is counting cards and the deck currently holds a statistical advantage.

Scanning Cards

- Taking the idea of shuffling after a raised bet a step further, a casino may have a device in the shoe or on the table that scans the cards and, keeps track of the remaining deck. However, while the card counter wants to see a deck loaded with face cards and aces, the casino wants just the opposite. Therefore, if the count gets too high, so to speak, it will trigger a reshuffle.

Continuous Shuffle Machines

- In order to eliminate any possibility for a card counter to keep track of the deck, some casinos implement continuous shuffle machines. These ensure that each hand has a freshly-shuffled deck, and therefore prevents card counters from gaining any statistical advantage.


While casinos across the board are doing their best to protect themselves from card counters, there are some cases where they do themselves more harm than good. For example, if a dealer were to shuffle after every three hands, this would certainly reduce the ability for the card counter to keep track of the deck in any meaningful way. However, it is also time consuming, slows down play and, therefore, there are fewer hands played per hour. Because the house almost always has the advantage in blackjack, it benefits casinos to encourage as many rounds of play as possible.


Depending on what state you happen to be playing in, there are varying shades of legal restrictions on casinos thwarting card counters. Some areas have none, so casinos can implement any or all of the aforementioned measures. However, other areas, casinos can only use measures that affect every player equally, as opposed to just targeting card counters.

As the technology of casinos – along with their motivation to maximize profits – continues to grow and develop, it is likely that these selective shuffling techniques will become more advanced and more common.