What is Shuffling?
Shuffling is the practice of randomizing a deck of cards so their order cannot be known by any of the players in the game. Prior to the shuffle, the dealer will often cut the deck to ensure he has not manipulated the cards in any way. Shuffling can be carried out by a croupier in a live casino, a shuffling machine often used in larger casinos, and by an algorithm in online casinos. Online casinos are free to develop their own shuffling algorithm, but this algorithm must be audited by the regulator before a gaming licence is issued.
There are a number of different shuffling techniques, but the one used in most casinos is the riffle shuffle because no cards are revealed during the shuffling process.
In a riffle shuffle, sometimes called a dovetail shuffle, the deck is cut roughly in half with both halves placed face down on the table with their back corners touching. The croupier then lifts the back corners with his thumbs while forcing each of the two halves together, he then releases his thumbs to allow the cards to cascade interleaved on the table.
If carried out correctly, the deck will form one of two types of riffle shuffle. If the upper card is interchanged with the second card, it’s known as an ‘in shuffle’. If the top and bottom card remain in position, it’s known as an ‘out shuffle’.
To accomplish true randomization, the croupier will shuffle the deck seven times. Whenever you shuffle a deck of cards, the chances of that exact sequence of cards ever having appeared before is extraordinarily slim because there are 52 ways to choose the first card, 51 ways to choose the 2nd, 50 ways to choose the 3rd, and so on. The maths for this looks like 52 x 51 x 50 x…x 2 x 1, etc. The answer is larger than 8 x 10 to the power of 67, which is a very large number indeed.
To put that number into context, if a person had been shuffling a deck of cards once per second, for every second since the universe began around 14 billion years ago he would have shuffled the deck only 10 to the power of 18 times. This extraordinary number makes it extremely unlikely that any sequence of cards has ever appeared before in the history of time.
Online casino card games use random number generators to determine which card is drawn next. The software is highly regulated to ensure entirely random outcomes at all times.