Non random shuffle & BS advantage
  • I seem to recall reading somewhere that if you play repeatedly through the same card deck(s) without shuffling then there is a tendency for high cards to follow high and low cards to follow low.

    The human shuffle isn't perfect so there could still be a slight bias for this to happen in normal play.

    I just wondered if anyone had investigated this and the possibility of altering basic strategy slightly based on the previous card played?
  • Red, That sounds a lot like something coming from the "Clump Card"
    people and I would recommend that you assume that to be total BS.

  • Ray,

    I found an interesting article written some time ago which to some extent answers my own question:

    It was written by Arnold Snyder and used statistics generated by Stanford Wong - these are respected names.

    If my interpretation is correct they confirm that if you don't shuffle then the order of the cards that comes out after several rounds of play do feature low cards followed by low cards and high cards followed by high cards, a situation which actually favors the player.

    However, they seemed to conclude that even the sloppiest of shuffles will remove this favourable effect and they couldn't find any other advantage left in the deck.

    Does anyone know if there have been more recent studies? It just seems to me that a sloppy shuffle would leave something behind....
  • Red, I'll go along with what ever Wong describes, but I don't believe he
    would recommend trying to focus on big card/small card sequence in any
    Casino environment.

    Bryce Carlson did a study on this topic and it involved several billion hands
    of sims. I think he varied the shuffle and the number of players in the
    game and looked for bias conditions, etc. I don't remember the location
    of the study, but if you search on Card Clumping and look for his name
    you should be able to find it. As always logic prevails and I think you will reach that conclusion as well.

  • Shuffle tracking can offer a definite advantage to the blackjack player. But for those who consider card counting to be "easy" shuffle tracking is considered "difficult".

    I don't know if a deck that is not shuffled will produce clumping or not. This is an interesting theoretical question, but doesn't have any practical use since all dealers shuffle cards.

    I would be a waste of time to look for a "sloppy dealer" or for decks that have been in use for a long time in the hopes of gaining some advantage, UNLESS you are a sophisticated shuffle tracker card counter.

    HOWEVER, there IS a disadvantage to playing the first shoe with brand new cards. This disadvantage disappears by the second shoe. So after the cards are changed, go take a 15 minute break and come back for the second or later shoe.

    I hope I don't come across as arrogant - you did ask a very good question and I like to encourage good questions.
  • I appreciate all the comments and please don't worry - nobody has come across as arrogant.

    I did the search and found the article mention by Bryce Carson. Very interesting.

    He investigated the effects of the non-random shuffle using simulation software and reached the conclusion that the shuffle would have to be very poor, i.e. unrealistically poor for there to be any difference to a basic strategy player.

    But he didn't investigate the effects of changing basic strategy.

    Consider a case of 16vs10. The card count is zero. The number of small cards and high cards on the table cancel out. Basic strategy says you should hit.

    However, lets just say that the last card dealt out was a 10. At the moment it's an very marginal decision anyway so what would happen if I followed 'clumping' theory, which says a high card is likely to follow, and decided to stand?

    I'd really like to see a simulation based on dealer shuffling and small basic strategy variations like this.


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