What is Edge Sorting?

[Note added 04.11.14]

Greetings to those of you who are landing here after following up on news of Phil Ivey’s edge-sorting lawsuit brought by Borgata. I just read about it today in this article at nj.com. You’ve come to the right place!

If you want a thorough introduction to edge-sorting, covering baccarat and other games, I highly recommend this article: Edge Sorting, 101 . Here is a complete list of edge sorting articles in this blog:

Otherwise, please enjoy the reading the following article …

About three years ago I was playing double-deck blackjack at a large off-strip casino in Las Vegas. OK, I admit, I was counting cards. But, honestly, I was just passing time waiting for someone I was going to meet for dinner. And besides, it’s hard not to count when I play. With a minimum bet of $5 and a maximum bet of $40, I was not a threatening presence. My hourly wage from this activity was about $8 – $10 on a good day. But at this point in my career, it was no surprise, indeed it was embarrassing, when I quickly got a tap on the shoulder.

I turned around and a well dressed man introduced himself as the table games shift manager. He said “Dr. Jacobson, we know who you are. What are you doing?” It was an awkward question and he was clearly uncomfortable asking it. And I was embarrassed as well.  As I got up from the table, we engaged in some casual conversation that blew off some steam for both of us. Talking about security matters in a general way, we gradually became focused on bigger problems.  I asked: “If there’s anything at all going on here that you want me to look at, any issue of security you can’t figure out, let me know and I’ll give you my opinion.”

What happened next was even more surprising. The shift manager explained that for the previous several months the casino had been hit hard by a card marking team. He said, “They seem to know what the cards are when they play.” But as he explained, the casino had carefully examined the decks again and again and could find no indication of the marks the team was leaving. He was sure they were marking, but there were no marks. How could that be?

I asked him to show me a deck of cards. He motioned to me to accompany him to a table in a closed pit and pulled out a fresh deck. The card pictured below is the card used by another Las Vegas casino, but it is similar to the one I saw. The striking feature of this card is that it is asymmetric. Two adjacent edges of the cards clearly have a blue half-diamond shape, while the other two edges clearly have a blue full-diamond shape. And every card in every deck had this feature.

Edge Sorting Card

The fact that the design is asymmetric allows the cards to be rotated by an edge-sorting team. The way this works is that a table is occupied by players who work together to rotate the cards to help read their values before they’re dealt. Certain key cards are rotated to have the full diamonds across the top and right edges, while other cards are rotated to have the full diamonds on the bottom and left edges. For example, in blackjack, Aces and Faces may be rotated one way, while all other cards are rotated the other way, allowing the players the ability to read the dealer’s next card.  Of course, the cards will get mixed up, but the team continues to sort them every hand, and after a few shuffles, most of the cards will be sorted. The fact that the casino deals, collects and shuffles the cards according to strict procedures is the Achilles heel.

I told the shift manager, “An easy fix for this is to have a turn in your shuffle. You do have a turn, don’t you?” His face showed a shade of white that would make Mary’s little lamb jealous and confessed that their shuffled did not include a turn. They had spent months investigating the way the team was marking their cards, while all along the cards that were being used were pre-marked. The team was using this casino’s own procedures and equipment against them. After a few minutes of taking it all in, my new best friend told me that he would be in touch and gave me his card. Needless to say, I never heard from him again.

I am not saying that casinos that use this type of playing card are making any type of mistake in their choice of product. Cards that can be edge-sorted are in wide use. Surveying my own collection of about 50 decks from various casinos, over two-thirds of them can be edge-sorted. The solution is to understand the particular security weakness of this type of equipment and to put in a trivial procedural fix. Every shuffle, whether it’s from a single deck, double deck, or shoe, should include a turn. Likewise, any game that uses an automatic shuffler should include a manual turn between rounds. The equipment being used wasn’t the problem – it was the procedure for using the equipment that was flawed.

I was recently visiting a casino that used a card that had the edge sorting problem. I observed their blackjack shuffle, and sure enough, it had a turn. I then asked a pit supervisor why the shuffle had the turn. The answer was dead on: “so the cards can’t be identified by some pattern on their backs.” I then went to the novelty game pit, where automatic shufflers were being used, and observed that no turns were in place. Clearly someone in management understood the need for a turn and that message was transmitted into the policies and procedures in the main pit. But, like may casinos, they didn’t take the protection of their novelty games seriously. Bad idea.

The lesson here is that nothing can be taken for granted in protecting games. Often the problems are little and can be quickly fixed. But unless you know the problem and know the fix, you may spend months wondering what they’re doing and how they’re doing it. Persistence is not always the answer to solving a problem.

12 responses to “What is Edge Sorting?

  1. Pingback: Phil Ivey Being Sued by Borgata Casino for $9.6m in Baccarat Dispute | World Casino Index

  2. Very nice article. I was brought here from the deadspin article today and wish I had started here. They use hundreds of words and don’t clearly explain what you do in several succinct paragraphs.

    What is the novelty game pit? What games do you consider novel for a casino, vs the main games?

    • Thanks for your nice words. Novelty games are games like Three Card Poker, Blackjack Switch and the other table games that are leased to casinos by companies such as SHFL and Galaxy Gaming. Traditional games are blackjack, craps, roulette, baccarat, etc.

  3. That was well worth the read. Could the casinos use this in their favor? Recently, I noticed that a casino near me, the house was winning everything. Could be something they did? Thanks, great article!


    This is just a extension of a system used successfully in the early 60s. Back then casino’s playing cards used in Reno casinos had a picture usually of the casino. If you looked at the cards from the top you saw one picture, rotate it 180 degrees you saw another These cards are two way cards.

    Players back then actually held their cards. They would turn 10s through aces one way and 9′s and below the other way. Dealer would hold the cards to deal and one only has to see the picture on the back of next card to get an advantage. When the casino’s found out what was going they switched to one way cards that looks the same looking at it from the top or bottom. ,

  5. Dr Jacobson,
    Thank you so much for sharing your knowledge. I used a webpage to write about the hot Ivey versus Crockfords case. I had no clue about edge sorting (see http://36casinogamblingtips.savyseph.com/ivey.htm)

    After finding your page, I was able to write http://36casinogamblingtips.savyseph.com/edgesorting.htm

    I was actually still in the dark but thanks to you video everything was crystal clear With that I was able to understand the edge sorting. I think that video link should be here.
    The video is nice, short and sweet but readers need to have a clue of the game that it is being applied to.

  6. what is the turn? and what is rotating cards? sorry, no clue but find this all very interesting

  7. FoolsGold — I agree. After this happened, I spoke with Stanford Wong about it. He told me that he would have said “For $10000, I’ll show you how they’re doing it, but you have to pay in advance.” Then, after he got the money, he told me that he would show them the 2 minute demonstration. I have long given it away — as this website shows.

  8. IF you want others to think of you as a professional you have to act as if you were one. He knew who and what you are, so he pays your consulting rate. I’d have invoiced him your minimum number of hours at your standard consulting rate. An informal and impromptu approach to you at the BJ tables does not negate the fact that you expect to get paid for professional services rendered.

  9. Fascinating.

    I’m a player, so I never really think about the game protection side of things. I thought that the turn was so that all four corners eventually got more-or-less the same amount of abuse during hand shuffles. LOL


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