His device was a box with an open top where the operator would place the deck. In 1878, Henry Ash proposed an apparatus to shuffle cards.

These machines were often complex with many mechanical parts to achieve card retrieval, shuffling and distribution with pseudo-randomness. It is unclear whether these devices were converted to commercial products or were discarded. Patents regarding card shuffling devices started to appear in the United States around the end of the 19th century. 2 Improving randomness using mechanical tricks.SIAM News later published a reasonably detailed discussion of its results. Batch shufflers are more expensive, but can avoid the problems associated with some continuous shufflers, whereby the shuffling operation only slowly changes the state of the deck, and new cards may be taken before shuffling has sufficiently randomized the pack, allowing some players to ' shuffle track' cards through the shuffling process.Ī widely reported, but unpublished, study by Persi Diaconis and Susan Holmes in 2000 resulted in the redesign of many shuffling machines.

Shuffling machines come in two main varieties: continuous shuffling machines (CSMs), which shuffle one or more packs continuously, and batch shufflers or automatic shuffling machines (ASMs), which shuffle an entire single pack in a single operation. The randomness or otherwise of cards produced from automatic shuffling machines is the subject of considerable interest to both gamblers and casinos. Shuffling machines have to be carefully designed, as they can generate biased shuffles otherwise: the most recent shuffling machines are computer-controlled. These machines are also used to reduce repetitive motion stress injuries to a dealer. A shuffling machine is a machine for randomly shuffling packs of playing cards.īecause standard shuffling techniques are seen as weak, and in order to avoid 'inside jobs' where employees collaborate with gamblers by performing inadequate shuffles, many casinos employ automatic shuffling machines to shuffle the cards before dealing.

Automatic card shuffler