Edge sorting is a technique used in advantage gambling where a player determines whether a face-down playing card is likely to be low or high at casino table games by observing, learning, and exploiting subtle unintentional differences on the backs of the cards being dealt. The technique requires the player to trick the dealer into rotating specific, high-value cards so that they are distinguishable from lower-value ones after shuffling.

Crockfords is a closed casino in London located on Curzon Street. The casino took its name from the former gentlemen's club in London called Crockford's.