How fair are your dice?

I bought the brazilian version of settlers of Catan, and suspected the dice that came with the game suffered of really shoddy brazilian quality manufacturing, because the game didn't was nowhere near fun as I had heard of it on Internet, with extremely frequent long rounds of nothing happening.

I tested the dice, by hand. And indeed, the dice, despite being a pair and thus theoretically greatly favoring 7, instead had a bias towards 2, 3, 11, 12.

Since most players put their important stuff on nunbers closer to 7, it became obvious why the game was sucking. (The match that made me go check the dice, had 4 turns in a row where even summing all players resources we still didn't had enough to build roads and do basic actions!!!)

Direct link to the original with all the juicy data: http://www.markfickett.com/stuff/artPage.php?id=389

Includes gems such as "I also tried rolling pigs from Pass the Pigs, but they did not roll sufficiently"

Dice can be unfair in a wide number of ways. Here are a few.

They can be weighted so that one face lands down more than others. One approach to detecting such weighted dice is to burn them looking for metal residue in the ashes. Cheaters got around that by simply hollowing out parts of the dice to unbalance them. Both metal weighted and hollowed out dice can be detected by dropping them in a glass of water and watching to see if they tend to turn while floating or falling through the water. Cheaters got around that common test by using mercury weighting with a chamber in the center where the mercury resides when the dice is to act fair and a connected chamber near the edge where the mercury is knocked to by the cheater rapping the dice on the table before a roll. Now, casino dice are clear to make it easier to detect weighted dice, but of course cheaters still try to put bits of heavy metal under the painted dots!

Dice can also me made in a fashion so that the tend to roll off some sides more easily. This, naturally, is more of a problem with dice that have beveled corners. Casino dice have nice sharp edges.

Instead of being rounded, some sides of the dice can be cupped, causing a suction cup effect that causes the dice to roll less easily off of one side.

Dice can be manipulated by narrowing them in one or more dimensions. Non-cubic dice may have just slightly smaller faces on some numbers or slightly slanted faces, making them roll in a non-fair fashion.

In the army, dice games are often played on the surface of a bed's blanket. Cheater put a small little burr below the surface in one of the dots to make it catch on the blanket fabric.

Finally, there are "joke store" dice with bad numbering, for example no single dot face.

A favorite of mine are a set of 4 dice with obviously strangely number sides. Bradley Efron [1] invented a way of numbering four dice so that no matter which die is chosen by your opponent first, there is a die that you can pick from the remaining three that will roll a higher value that your opponent two-thirds of the time!!!

[1] https://en.wikipedia.org/wiki/Bradley_Efron

Reminds me of the great Dice-O-Matic by GamesByEmail: http://gamesbyemail.com/news/diceomatic

I've been told that the fewer times your die bounces, the more random the roll will be. The reason given was that each time it bounces, you give an opportunity for a slightly heavier side to roll towards the bottom. Obviously you should be wary if someone's roll doesn't bounce at all -- they are likely manipulating the throw (make them use a dice cup!). But a too-bouncy table can cheat you too by favoring the heavier side of the die.

So, your dice may be trying to kill you, but they're not working alone. Blame the table too!

Here's someone testing d6s to see if 1's really do come up more often. He used student labor instead of a machine.

http://www.dakkadakka.com/wiki/en/That%27s_How_I_Roll_-_A_Sc...

>If you're rolling it and getting lots of 4s and 3s, it's because your die is messed up.

Video quickly went from science to BS. Random results and even distribution are not the same.

And this is the #1 reason I rejected D&D 3rd edition when it came out: higher was always better. (okay, not really)

In truth though, in previous editions it was not consistent, so you never knew if higher or lower would be required of a particular die, and sometimes it would be at the DM’s discretion.

Your "lucky" (cleverly microwaved) dice were no match against the true genius baked into 1st edition.

This is a very interesting experiment, but I was wondering if the dice rolling was sufficiently natural / random. The can automatically rotates at 90 degrees, but when it comes back up, the dice seems to spin a lot on the vertical axis, showing bias towards the upper half of the faces. However, I did not see what effect the first half of the motion had on the dice.

I'll be that guy... https://xkcd.com/221/

Hickory dickory dock.

The Diceman is never fair.