Biased Dice

[Christian]

So, here I was, innocently testing an adventure for lethality, when I found myself feeling that the d20 I was using was rolling with an odd distribution. I'd just found it in a corner, and hadn't really used it before, so I got to wondering if my feeling was justified. So, I cranked up Excel & analyzed 100 rolls in a chi-square. Not enough to say anything definitively if there were a small bias, of course, but the results were reassuring that I had a fair die ... Then, since I was still puzzled by my intuitive feeling, I grabbed my 'old faithful' black d20 that I generally use in games, and ran that through the same test. And some more-with only a hundred rolls, even a weird result could be chance, better do a few hundred more ...

Definitive result: I've been using a biased die in my games for years. So that's why the new d20 felt 'off'-it was actually fair, so I wasn't seeing the results I was used to. It wasn't so far off that it would be obvious (unlike the old d20 with a chipped corner I used to have that would roll 18 or 20 about a third of the time); it has a slight bias in favor of 3, 15, and 18, and a strong bias against 16, for some reason. The overall average roll is still right around 10.5, so I haven't been getting an advantage or disadvantage, but still ... Anyone else have any experiences like this? Have you ever found a 'bad' die & kept using it for some reason? (C'mon, tell the truth!) Share your stories!!

 

[Thornir Alekeg]

I have my red d20 from my Basic Set back in 1980. Its colored with yellow crayon, is my "emergency die" and has become the stuff of legends with my long-time gaming friends. I have never tested it statistically, but far too many times it has pulled my bacon from the fire with a natural 20 right when I need it. I think the corners have become a little more rounded such that it has a preference for rolling 20s or the adjacent face. It is not something I planned, it has just happened through regular use. I never use it when DMing and only use it in a critical situation for my PC. As long as I do not abuse using the die, my DM accepts the fact that it is probably not completely unbiased.

 

[AuraSeer]

I don't have any biased dice that I know of, but I do have one of the old sneaky d20s that is numbered like a d10. It once got accidentally mixed in with my DM's dice, and he used it for quite a few attack rolls before realizing what it was. (I think he started to get suspicious when he saw it come up 0. )

 

[Jdvn1]

I always use this die that rolls 1's or 20's almost all the time. It's a very risky die, I always use it for stabilitizing. "Ten percent chance to stability? I choose a 1 and 20 on my d20. ... There we go."

Kind of sad, I know.

 

[Yig]

I have a pair of d6 that I use to play Blood Bowl since they tend to maim and kill more than my other dices.

Can't pickup the ball with those tho

They're great for violence but sucks at everything else.

 

[Lord Judas]

Definitely. Ive got a "10's" d10 that comes of "10" (crappy) as many times as all the other numbers put together. Ive been able to roll "10" 4 times in a row with it a few times, and 3 times in a row is fairly common. Rolling up random magic is a total drag/chore since I have to keep re-rolling again and again or the party would never get much more then a Potion of Cure Light Wounds. I dont see any obvious reason for this, but its true. Ill prolly buy a new set of dice soon at any rate. Can never have too many dice

 

[Imret]

Absolutely. While I don't have dice that favor specific numbers, except for the magic "d7"; it's a d8, but you're almost assured a 7 when you roll it. It's also called the Cure die.

However, I think the most notable are my blue-and-white dice. I bought a full tube of them upon dropping into my FLGS and discovering dice had actually gotten CHEAPER since the year before, and we were about to start a new massive campaign, so I got a matched set for my new character...and they were glorious. High rolls, lots of crits, and miss chance for blindness was almost a joke. I was amazed by them In time, the campaign ended, and the dice fell into my circulation.

They have since been so disastrous they've been largely responsible for the deaths of sixteen different characters over four years. Failed skill checks, saving throws, combats I couldn't have hit my own head with both hands and a map.

I now own a set of dice that exist solely to fail.

 

[Lord Judas]

Definitely. Ive got a "10's" d10 that comes of "10" (crappy) as many times as all the other numbers put together. Ive been able to roll "10" 4 times in a row with it a few times, and 3 times in a row is fairly common. Rolling up random magic is a total drag/chore since I have to keep re-rolling again and again or the party would never get much more then a Potion of Cure Light Wounds. I dont see any obvious reason for this, but its true. Ill prolly buy a new set of dice soon at any rate. Can never have too many dice

 

[Castellan]

This isn't so much a "slanted die" story as a "slanted player" story (sorry for the brief hijack).

At our most recent game session where I'm a player, we were in pretty deep doo doo. Our group had been surrounded by drow and they had really gotten the drop on us. As fellow players fought desperately to survive, I began pointing at their still-rolling d20s and saying "natural 20!" And lo! from each die, a natural 20. I didn't do it for every roll, but on rolls I "felt" were critical, I'd point and do it again. I ended up with 6 pairs of wide eyes staring back at me each time I did it.

I've never believed in "mental powers," but that was sure freaky. Fun... but freaky.

 

[kmdietri]

I find the white d20's that came with the starter sets of the new plastic minis only roll 1,2,3,18,19,20.

I guess it works out to average in the long run but they can be really deadly...