Wednesday, July 1, 2009

Shuffling techniques

Several techniques are used to shuffle a deck of cards. Some techniques are easy to learn while others achieve better randomization or are better suited to special decks.

Riffle

A common shuffling technique is called the riffle or dovetail shuffle, in which half of the deck is held in each hand with the thumbs inward, then cards are released by the thumbs so that they fall to the table interleaved. Many also lift the cards up after a riffle, forming what is called a bridge which puts the cards back into place. This can also be done by placing the halves flat on the table with their rear corners touching, then lifting the back edges with the thumbs while pushing the halves together. While this method is more difficult, it is often used in casinos because it minimizes the risk of exposing cards during the shuffle.

Stripping or overhand

Another procedure is called stripping, overhand, or slide shuffle, where small groups of cards are removed from the top or bottom of a deck and replaced on the opposite side (or just assembled on the table in reverse order).

Hindu shuffle

Also known as "Kattar" or "Kenchi" (Hindi for scissor). The deck is held face down, with the middle finger on one long edge and the thumb on the other on the bottom half of the deck. The other hand draws off a packet from the bottom of the deck. This packet is allowed to drop into the palm, then put on top of the first half. The maneuver is repeated over and over until the deck is all in the second hand. Hindu shuffle differs from stripping in that all the action is in the hand taking the cards, whereas in stripping, the action is performed by the hand with the original deck, giving the cards to the resulting pile. This is the most common shuffling technique in Asia and other parts of the world.

Pile shuffle

Cards are simply dealt out into a number of piles, then the piles are stacked on top of each other. This ensures that cards that were next to each other are now separated. The pile shuffle does not provide a good randomization of the cards (but this can be enormously improved by dealing to the piles in a different order each circuit, not always in the same order). It is sometimes used in collectible card games where other forms of shuffling can be damaging to rare cards.

Corgi, Chemmy or Wash shuffle

Also known as the Wash or Corgi, scramble or beginner shuffle this involves simply spreading the cards out face down, and sliding them around and over each other with one's hands. Then the cards are moved into one pile so that they begin to intertwine and are then arranged back into a stack. This method is useful for beginners and small children or if one is inept at shuffling cards. However, the beginner shuffle requires a large surface for spreading out the cards and takes longer than the other methods. The now often used name Corgi, originated in Yorkshire, England. It has spread and is used in many parts of the UK, and often heard in international poker rooms or tournaments such as the WSOP or EPT. It is quite common in casino poker rooms for dealers to use this method upon introducing a brand new deck, which are packaged in ranked order by suits, before shuffling it by some other means (i.e., a riffle shuffle or shuffling machine).