Shuffling is the critical first step to every quality card game. Consistent, proper shuffling produces a randomized deck of cards and ensures a fair game for all players.

Shuffling is the procedure used to randomize a deck of playing cards and provide the right element of chance in card games. If the cards aren't properly shuffled, some players can predict which cards will most likely come up later, potentially giving them an advantage. Although some games do not require a truly randomized deck of cards, serious card players prefer a truly randomized deck. This is particularly true when playing for money.

Although there are many shuffling techniques, the most common method is a riffle technique where approximately half of the deck is held in each hand with the thumbs facing inward and the cards are then released by the thumbs causing them to intertwine.

Riffling alone has its flaws because the cards in the top section of the deck could remain in the same position if the deck is not cut evenly. Example: place four aces on top of the deck and cut the deck so the top section has more cards than other side (i.e. 29/23). The four aces will stay on top after a riffle because the cut was top heavy. About 6 cards on the top section did not get riffled. Therefore, it is critical that the deck be cut as evenly as possible when relying on this method alone.

For the above reasons, a proper shuffle combines Riffling with something called “Stripping”. The stripping technique is where small groups of cards get removed from the top or bottom of a deck and replaced on the opposite side (top-to-bottom or bottom-to-top). The effects of a top-heavy riffle are therefore eliminated by combining several strips with the riffles.

Casino dealers generally combine three riffles with several strips between second or third riffle cycle. This is widely known as the "Casino Dealer's Combination."

Although the Casino Dealer’s Combination is generally considered to be adequate for normal play, according to the experts it takes 6 to 7 good riffle-and-strip sequences to truly randomize a clean deck of playing cards.

For more information, the topic of shuffling methods and randomization has been posted on Wikipedia and The Mathematical Association of America:

The “Faro Shuffle”:
Did you know that cutting the deck exactly in half and riffling eight times with perfection will bring the deck of cards back to its exact initial sequence? This is called a "faro shuffle".

You can test this without using the whole deck. Take the ace through five-of-hearts and the ace through five-of-spades from your deck. Now make two adjacent rows of cards: Place Hearts on the right in order facing up and Spades on the opposite side in order facing up. Starting from the right, place one card at a time to the center: ace-of-heart, ace-of-spade, two-of-hearts, two-of-spades, etc. Then cut the deck when finished exactly 5 cards from the top to the right and 5 cards to the left. Repeat several times and the deck will revert to the original order.

Sleight-of-Hand:
Unfortunately, “card sharps” know many different ways to control the deck through sleight-of-hand while appearing to shuffle properly. They can use false shuffles and false cuts that appear to randomize the deck but actually leave the cards in the exact same order. More advanced techniques include "culling", which is manipulating desired cards to the top or bottom of the deck, and "stacking", which puts desired cards in a position to be dealt. Card sharps also cheat by dealing either the bottom card from the deck or the second one from the top instead of the top card. These are called the "bottom deal" and the "second deal" respectively.

Card sharps don’t represent a real threat when playing among friends and family, but games with decent prize money will attract cheaters. In either case, the full randomization of a good shuffler will increase the integrity of your game.

The Shuffle Tech Solution

A fully automatic shuffler speeds ordinary play and eliminates the integrity problems mentioned above. The world’s best swindlers cannot employ sleight-of-hand when they cannot shuffle the deck of cards themselves.

Shuffle Tech machines replicate hand shuffling - the most time-tested, reliable method of shuffling. In fact, hand shuffling is used by casinos when the stakes are highest—when the highest level of security and randomization is required. Our technology now allows you to automatically replicate hand shuffling for the first time. The two different hand-shuffling sequences offered by Shuffle Tech include:

Casino Dealer’s Combination: At the press of a button and in under one minute, automatically recreate the casino dealer’s favorite: : 1 riffle, 1 strip, 1 riffle, 1 strip, 1 riffle. There are a total of 3 riffles with 2 stripping sequences.

Full Randomization: Press Shuffle Tech's 7-riffle start button for full statistical randomization: 1 riffle, 1strip, 2 riffles, 1 strip and 4 more riffles. There are a total of 7 riffles with 2 stripping sequences.

In addition, Shuffle Tech machines are designed with a translucent cover to ensure that the shuffling process is visible to all players. You would never allow your dealer to hide the deck while shuffling, so why allow a black-box shuffler where the shuffling is invisible to everybody?

The problem with random number generators:

Shuffle Tech has intentionally avoided using a computer-based random number generator to sort and shuffle cards for home games and other non-regulated tournaments. Random number generators may be acceptable in secured, regulated environments, but in unsecured environments it is too easy for clever computer programmers to update the programming and stack the deck in their favor.

Also, shufflers with random number generators are often designed to know the value of each card shuffled through it. One advantage of that is the ability to count the cards and ensure a full deck, but the major disadvantage is the fact that if the system is altered, the order of the deck can be controlled by the operator.

Proof of Randomness:

Handshuffling is the most time-tested, reliable method of shuffling. Click the links below for more information about mathematical proof of randomization from hand shuffling: