Dice (singular: die) are high-impact polyhedra. In role-playing games and tabletop war games, they are used as randomizers to inject an element of chance into the game. Non-gamers often only know about the six-sided die (hereafter referred to as the d6) thanks to the ubiquity of games like Monopoly and Yahtzee. Which dice are used tends to vary by system. Dungeons and Dragons, for instance, makes use of all types. On the other hand, White Wolf games and Classic Traveller use only ten- and six-sided dice, respectively. On the gripping hand, some games don't use dice at all! These tend to be relatively new games like Nobilis or Amber.
Bear in mind, if you're not familiar with how statistics work, one d12 does not have the same probability distribution as two d6s (same goes for any combination of die). A single die will have the same percentage chance for any side to roll, whereas using multiple die will result in a probability distribution resembling a bell curve (in the two d6's case, seven will be the most common roll, followed by sixs and eights, then fives and nines, and so on). Keep this in mind when you're doing homebrew rules.
If you do not have dice for whatever reason, consider chits.
Dice are considered by most people to be impartial arbiters of random chance. Fa/tg/uys (and craps players) know better. Dice are controlled or at least influenced by the unseen force of Dice Mojo. It is believed that Dice Mojo can be influenced by players through manifold rituals, including:
- Placing a die with the desired number upward, that it 'gets used to' that position and tends to return to it.
- Placing a die with the desired number downward, that the die is tricked into thinking it has already made a bad roll and will produce a good outcome on the subsequent roll.
- Rolling a die until a string of good rolls are achieved, tapping into a streak of 'good mojo' or 'rolling out' bad outcomes.
- Various chants, prayers, threats, and curses made toward the die in order to entice or coerce it into producing favorable rolls.
- Being careful not to drop dice or just roll them to pass the time till next turn, as when rolling a twenty, the critical ratio may be "used up" for the day.
- Building dice towers as tribute to Dice Gods that they may bless one's dice with good Mojo.
/tg/ The dice are magical beings, and should be treated as such. Anger the dice, and your life shall cease. Please the dice, and it shall reward your courageous behavior. Worship the Dice. Dice is love, dice is life.
Types of Dice
An elusive creature, the d1 is guarded by the elder neckbeards.
A d2 isn't a die - it's a coin.
You flip the fucking thing. Heads count as 1, Tails count as 2.
You can, alternately, roll any other die - counting odds as 1 and evens as 2.
In Various Works
d2s are used with disturbing frequency in both CCGs and RPGs. They are used in Magic: The Gathering, and even Dungeons and Dragons because some faggot developer thinks it's fucking funny to have certain items and weapons do damage using d2s even to this fucking day.
The RPG Bean! is a d2-based game, and it's actually pretty good.
The d2 are the only dice you can put in a vending machine and spend for candy.
Not much to say about it.
Warhammer 40k uses D3's every once in awhile - Rending, Manticores, & other cases such as +D3 attacks, 2 + D3 objectives, etc. Most of the time, they don't actually use a D3 - they just roll a d6, at which points two schools of thought engage in a holy war:
- Some subtract 3 from any result that's 4 or higher. So, for example, a 5 becomes a 2.
- Others divide the result by two, rounding up. So, for example, a 5 becomes a 3.
The 40k rulebook explicitly proselytizes the latter, which means the former is heresy. Other games don't really care as much.
Actual d3s come in two major flavours: The weird triangular nublette things seen to the right, which are largely used by people who think having weird dice makes you interesting, and d6es which had 1, 2 and 3 written on them twice, used by people who like to build things out of dice.
Since you can readily simulate a d3 result easily enough without obtaining extra dice why in the hell would you bother?
A pyramidal die that has the second-sharpest points of any die (only the d8 is sharper), and, appropriately enough, has four sides. Used by Wizards, small weapons, and low-caliber firearms in d20 modern. At least it gets more love than the d12, which probably falls asleep every night in a pool of tears and melted butter.
There are two ways to print the numbers on a D4. On one, the numbers are arranged on the corners of each face, and so the number at the top (it will always be three of the same number) is what you actually rolled. On the other kind, the numbers are arranged in the middle of each side of the face, and so the number on the bottom (again, it will always be three of the same number) tells you what you rolled. Oldfags will insist the "numbers on the bottom" d4 is the one true way, despite the fact that they need the full power of their coke-bottle glasses to see the numbers. Don't argue with 'em, just keep using the d4s that you and everyone at the table can read.
Whilst the d4 isn't as sharp as a d8, it has one major bit of natural defense - no matter what way it lands, it will have a point face-up. Because it's the smallest die, care needs to be used - if one escapes its dice-box and into the wild, it will wait, with its natural weapon ready, for the exact moment someone walks into its vicinity barefoot to strike, whereupon it will inflict some surprisingly-vicious puncture wounds.
Somewhat related, in D&D Caltrops inflict 1d4 damage. Coincidence?
If you don't know what a d6 is, holy shit are you in the wrong place. Go back to playing monopoly in your blissful ignorance that uses two of them.
Fun Fact: Do you own a regular #2 pencil? If so, congratulations, you have a d6.
A die-rolling method for numbers from 0-5 with a particular curve.
Roll two d6, and subtract the smaller from the larger.
The curve looks like this:
The eight-sided die is an octohedron: one of the symmetrical polyhedral known as the "Platonic solids."
It looks like two pyramids caught in the beautiful act of reproduction. Long live the dice race.
A d8 was always used for hit points for Dungeons & Dragons monsters, and in Advanced D&D it was used for those classes that have more hit points but weren't supposed to be as butch as Fighters or Paladins.
Eight-sided dice also have the most variations with weird not-numbers stuff on them, like compass directions, random weather, letters. They're also used as below-bargain-basement minifigs because one point is always off the table, like a big nose, or turret.
When you played Dragon Dice, the d8s were the terrain, which could change under your feet without moving your army, somehow.
James Ernest came up with a game "Dogfight" that uses d8s for their numbers, for being pointy and for turning in circles when you try to roll them like wheels... then he remembered that people put weird shit on d8s and he came up with a new game called "DiceLand," which is a beautiful game.
Fantasy Flight Games fucking *loves* themselved some d8s. Their games make you wonder if all their parents were killed in a horrible cube-shaped accident.
It's a die. With ten sides. Pretty simple concept.
It's in the shape of a pentagonal trapezohedron. You can stand it on its point and spin it like a top.
The tenth side usually bears only a zero, but you should still read it as "ten" because you want your result to be 1-10, not 0-9.
Rolling d100 Using Two d10s
Get out two d10s. Use one die to denote the singles digit and another die to denote the tens digit. Some d10s have two digits per side (see above) to make differentiating your digits easier, but you can roll d100 with any two d10, provided you specify beforehand which die is the tens and which the ones.
Reading it off is simple. Did you roll a 20 and a 4? That's a 24. A 90 and a 1? 91. A 00 and a 5? Just a 5.
The only possibly ambiguous result is two zeroes: a 00 and a 0. Obviously you rolled a 100. Why? Because the alternative is a 0 which you can never roll with any other die. That, and the system assumes a roll from 1 to 100, not 0 to 99.
Mathematically, each digit is determined in an independent manner. There are exactly 10*10=100 two-digit combinations, all equally likely. You now have a uniform distribution of 100 different results, as desired.
The d12 is the loneliest die. It is used for barbarian hit dice and greataxe damage in Dungeons & Dragons. The fact that Orcs (and Half-Orcs) are both the most common barbarians and the most common wielders of greataxes, it is suspected that Gruumsh is the head of a conspiracy aiming to eliminate the d10 in favor of the d12, in order to "purify" dice sets so that they consist only of true platonic solids.
Observant smar/tg/uys will notice that d12 are the hitdice used for undead and dragons instead of the usual d8s.
Used basically just in Blood Bowl to randomly select a player on a team (which has a max of 16 players). Originally introduced by the NAF in 2013 (when G-Dubs refused to license their block dice anymore), GW wised up in their 2016 edition of the game and added it to their product line, replacing the old method of drawing a chit from a cup.
| The d20 System for role playing came later.
Like eighteen centuries later.
Only ever used for those critical-hit tables when you rolled a natural 20. Or if your DM was rolling damage and felt like being a dick.
But man, would it leave a bruise when your little sister threw it at your head.
For when you want to do 2-100 points of damage with a vaguely normal distribution.
... yeah, I don't know either
It also doubles as a golf ball.
Take that, D50's.
Apparently it took about 6 years to make this die. I guess this means that it takes 6 years to put the numbers 1-100 on a fucking golf ball.
It may seem awesome when you see it, but as soon as you get one (and whoever's selling it to you is also aware of how unspeakably lame it is, and will probably even tell you) you will find that it has two major flaws: it takes about a minute to stop fucking rolling around and if you aren't blessed with a perfectly level playing surface you will never find out exactly what you've rolled (and when there are six other numbers right next to the 100 and 1, that's a pretty big problem). Oh, and to top it off, it isn't even very balanced, so it's effectively a loaded die.
On the other hand, if you hate your friends, show up to your next meeting and sweep all the d10s off the table, then drop your d100 right in the middle with a theatrical gesture and watch as everyone is mesmerized by its incessant rolling (see: takes about a minute to stop fucking rolling around). Take this opportunity to pocket the d10s, run away and never come back.
FATAL seemed to expect you to use this (but then again FATAL expects you to play FATAL so you can't expect much).
This is the most number of sides that a die can have while being 'mathematically fair die' (that doesn't have the dual problems of rolling forever and being prohibitively hard to read). The d120 stops rolling after a reasonable time (with the condition that this only applies if you don't roll with 'too much force'). It is also a bit tricky to read (but still perfectly possible). The company that sells the die points out that it can can act as any of the standard 7 dice (d4, d6, d8, d10, d10 of 10s, d12, and d20). And thanks to the chart they released for free, you don't even have to do the math yourself . Of course for the d100 roll you'll have to roll the d120 twice, roll 2 d120, or use a die other than the d120 (although you could still use the d120, e.g. a d10 and a d120). 
- Barrel dice
- Chits - The nega-dice of yesteryear.
- Crayola Dice
- Dice pool
- Exploding die
- Fudge dice
- D6 System
- D20 system