Edge Sorting
The technique of identifying manufacturing imperfections in playing card designs to gain advance knowledge of card values — made famous by the Phil Ivey legal battles.
Edge sorting is an advantage play technique that exploits asymmetric patterns on the backs of playing cards caused by imprecise cutting during manufacturing. Most standard playing cards have a repeating pattern on their back that is — due to manufacturing tolerances — not perfectly symmetrical when rotated 180°. An expert edge sorter can identify which side of a card has a slightly different border pattern and use this to determine the card's value before it is flipped face-up.
The Mechanism
Many premium card decks use a pattern with a slightly differently-sized repeating element on the long edge depending on the orientation. When the card is rotated 180°, a trained observer can distinguish the 'good' side from the 'bad' side under normal casino lighting conditions.
In baccarat, where knowing whether a card is a high-value card (particularly a 6, 7, 8, or 9) before the hand resolves is extremely valuable, edge sorters have been able to generate significant positive expectation.
The Phil Ivey Cases
The most famous edge sorting incidents involve professional poker player Phil Ivey:
- —Crockfords Casino, London (2012): Ivey and associate Cheung Yin Sun won approximately £7.7 million at punto banco over four baccarat sessions using edge sorting. The casino withheld payment. The UK Supreme Court ruled in 2017 that Ivey had obtained winnings by cheating (not through illegal technique, but through the legal lens of 'obtaining by deception' — he had manipulated casino staff into rotating specific cards).
- —Borgata Casino, Atlantic City: Ivey won approximately $9.6 million. The Borgata successfully sued Ivey for the return of winnings plus damages.
In both cases, the courts found that while edge sorting requires skill and observation, the active manipulation of casino procedures (directing dealers to rotate cards under pretexts) crossed a legal line.
Casino Countermeasures
- —Regular card rotation during shuffling
- —Card designs that are perfectly symmetrical on all edges
- —Automatic shufflers that randomise card orientation
- —Replacement of cards mid-shoe upon suspicion
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