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United States Patent 6,254,096: Shuffle Master's Continuous Shuffler

3 April 2004

By John May

United States Patent 6,254,096 was supposed to be the death knell for blackjack card counters.

This was Shuffle Mmaster's patent for their continuous shuffling machine (CSM). This device was supposed to kill off card counting forever by shuffling up every hand and do away with human shuffling, speeding up the game in the process. For a variety of reasons it hasn't worked out like that. The public has rightly boycotted these devices and the tide has turned against CSMs. The major threat to card counters now comes from a cocktail of new games and procedures: Spanish 21, SuperFun21 and, worst of all, 6:5 single-deck blackjack.

However, these machines are still in many casinos and the patent contains a lot of useful information about them. Unlike much of what is written about gambling, you can be reasonably certain that the patent is both accurate and true. A patent is a form of insurance, legal protection against intellectual theft. If it is inaccurate in any way, the legal protection it offers is useless.

Much of the patent deals with the workings and components of the device and is not of direct interest to the card counter. However, certain sections of the patent are very interesting. In particular, there is an examination of patents filed on previous patents for past continuous shuffling machines. The patent is candid about the threat card counters posed to past devices, in direct contrast to what was commonly thought at the time, that CSMs could not be beaten. Some sentences stick out. For example: "Although the Hoffman shuffler was commercialized, it never achieved a high degree of acceptance in the industry. Card counters could successfully count cards shuffled in the device, and it was determined that the shuffling of the cards was not sufficiently random." And: "The size of the buffer supply of shuffled cards in the known continuous shufflers is large, i.e., 40 or more cards in the case of the Blaha shuffler. "

But the most interesting passage of all is this one: "Randomness is determined in part by the recurrence rate of a card previously played in the next consecutively dealt hand. The theoretical recurrence rate for known continuous shufflers is believed to be about zero percent. A completely random shuffle would yield a 13.5% recurrence rate using four decks of cards. "

What this is saying is that all CSMs designed prior to the latest Shuffle Master model or not based on patent in question do not immediately redistribute cards back into the machine. These machines can therefore be counted on a round-by-round basis at a constant point of deep penetration. By statistical analysis you can determine how long it takes for cards to be recycled and work out your overall advantage. A method explaining how to do this is outlined in my Get The Edge At Blackjack.

Incidentally, Shuffle Master's own device is not completely perfect either. "It has been demonstrated that the apparatus of the present invention provides a recurrence rate of at least 4.3%, a significant improvement over known devices. " Admittedly 4.3% is close to perfect. The Shuffle Master would redistribute cards quickly enough to foil all conventional card counting methods, unfortunately.

A further intriguing possibility arises from a reading of the patent. Games such as Caribbean Stud (CS) and Let It Ride (LIR) use continuous shuffling machines as standard. I always thought that the continuous shufflers would recycle cards instantly, but the Shuffle Master patent says clearly that this is not the case for any shuffle machine designed in the United States. This leads to the possibility that cards played on one hand of LIR or CS may not reappear, or are less likely to reappear in subsequent rounds, which would change the overall odds.

John May
John May is one of the most feared gamblers in the world. He has developed "advantage play" techniques for many games that are considered unbeatable.

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