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Most Six-Sided Dice Biased by 75%

posted Wednesday, June 23rd 2010 by Jonathan Drain
News, Reviews & Culture

The myth is true: Warhammer six-sided dice roll 1s more often. That’s the conclusion of an American engineering professor who rolled dice 144,000 times and dissected them using a hydrogen-cooled diamond saw.

The experiment tested Games Workshop dice, Chessex dice, and precision casino dice. The GW and Chessex d6s rolled a ‘one’ 29% of the time, when the average should be one in six or 16.6%. That makes the dice almost 75% more likely to roll a ‘one’, giving your rogue a crappy damage roll or your Warhammer unit a pass on a leadership test. The casino dice were spot on at 16.6%.

The best theory is that rounded edges cause dice to keep rolling longer. Gravity paradoxically favours the heaviest side at the top, since gravity causes dice to stop rolling:

Game room logic, poor source of anything, would dictate that the side with the one is heavier and would therefore be on the bottom more. Unfortunately this is just not true, take popcorn or batholiths as an example. The 6 is too light to stop the momentum of the dice, the rounded corners cannot prevent the dice from turning due to the weight. In the end 1s are by far the most common result.

Dice inventor Lou Zocchi has a similar theory.

But who is this anonymous professor? Could he be a secret plant for the manufacturers of casino dice?


  1. Most Six-Sided Dice Biased by 75% « The Matrix Data Bank

    June 23rd, 2010

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  2. Sian

    June 23rd, 2010

    Not a new article (it’s been kicking around since 08) but it’s good to bring up now and again,and lends subjective evidence for the ‘lucky/unlucky dice’ that everyone has.

    Personally, any future dice purchases of mine will be Gamescience. Lou knows his stuff, and what would you rather have, pretty dice, or dice that actually do their jobs? Dice with a bias (one way or the other) kind of wreck the whole reason for using dice in the first place.

  3. Stu

    June 24th, 2010

    While I want to believe this professor’s test results, I am reluctant to do so.

    The fact that he’s remained anonymous and has (as far as I could tell) never released his data, makes me suspicious.

  4. We already knew this « Under a Gibbous Moon

    June 24th, 2010

    [...] James on Jun.24, 2010, under Random In yet another case of a scientist with too much time on his hands, and engineering professor rolled them bones some 144,000 times. He found that will roll a one [...]

  5. Alex Schroeder

    June 24th, 2010

  6. My Dedicated DBA Dice « My Little Soldier

    August 1st, 2010

    [...] Check out this link for an eye-opener: http://www.d20source.com/2010/06/most-six-sided-dice-biased-by-75 [...]

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