Who invented modern card shuffling?

Modern card shuffling has no known inventor. The oldest technique involves moving packets of cards from one hand to the other, while the riffle shuffle interleaves two halves of the deck. The latter became popular during the 19th and 20th centuries thanks to thinner, more durable cards that could withstand bending.

The overhand shuffle

You hold the deck in one hand and drop small packets into the other. It’s comfortable, doesn’t damage the cards and has been used in bars and homes for centuries. The drawback is that it doesn’t mix the cards very thoroughly: you need plenty of passes.

The riffle shuffle

You split the deck into two halves and let the cards fall so that they interleave. This requires flexible playing cards, which is why it became widespread as materials improved. We cover this in the evolution of playing card materials.

The mathematics of shuffling

In the 20th century, mathematicians such as Persi Diaconis studied how many riffle shuffles it takes to thoroughly mix a 52-card French-suited deck: about seven. We explain this in how many times should you shuffle?.

Shuffling machines

Casinos and tournaments now use automatic shuffling machines. In online games, the cards are dealt by a program that generates random sequences. If you’d like to learn to shuffle by hand, take a look at our guide to how to shuffle properly.