[[BillyVsSNAKEMAN http://tvtropes.org/pmwiki/pub/images/The_RNG.jpg]]
[-[[caption-width:100: [[CodeGeass The only people who should roll dice are those who are prepared to roll a 1]].]]-]

->''"If a statistician hands you a die insisting that 'any given roll has the same odds of rolling a one or a twenty', it means '''he's handing you a depleted die in the hopes of taking advantage of you'''. Don't fall for it!"''
-->--Shamus Young ''[[http://www.shamusyoung.com/twentysidedtale/?p=1223 DM of the Rings]]''

A [[YouFailStatisticsForever statistician]] can tell you that properly generated random numbers will follow a discrete uniform distribution, giving you a roughly equal chance of rolling very good or very bad numbers. He may wax eloquent about how pseudo-random numbers are generated in computers, and how dice are wonderful randomizers. A good statistician will even disabuse you of the notion that a six sided die has a 1/6 chance to land on any one side; most dice are not built to that kind of precision. (Casino craps table dice are. They're also more expensive.)

A gamer, either of the [[TabletopGames tabletop]] or [[VideoGames console]] variety, will tell you that this is all a load of dingo's kidneys. The characters that gamers play live and die on good or bad rolls, and even if your dice are perfectly square and uniform, even if your game uses cryptographically strong random numbers, these numbers do not follow "distributions" or "probabilities." Instead, they usually produce whatever number you ''[[FinaglesLaw really didn't want]]''. Unless, of course, you know the proper way to placate the Random Number God: then the dice will smile upon you. Usually.

The name of this trope comes from {{Angband}}'s and NetHack's fanbases ([[TropeMaker coined in the Angband fanbase]], [[TropeCodifier spread by Nethack's]]); both games are partially {{Luck Based Mission}}s, considering how many [[KilledOffForReal Instant Death]]s there are, and the players of both games have been known to build altars to the "RandomNumberGod" or curse his/her/its name. Or both.
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!!Examples:

* [[http://archive.gamespy.com/comics/dorktower/images/comics/dorktower636.gif This Dork Tower strip]] was the beginning of an arc about scheming dice that started behaving only when the cats got a hold of them.
*Sometimes, the power of the dice can get a little [[http://nodwick.humor.gamespy.com/ffn/index.php?date=2005-06-23 out of control]]. Efforts at appeasing the dice may [[http://nodwick.humor.gamespy.com/ffn/index.php?date=2005-07-12 meet with failure]].
**A strip in ''Real Life Comics'' parodies the idea of THAC0 where the main character misses a stationary enemy that wasn't focused on him because he rolled too low to hit it.
* There's a sort of DoubleSubversion to this concept, detailed in the annotations to [[http://www.darthsanddroids.net/episodes/0099.html this]] ''DarthsAndDroids'' strip, which involves "rejecting that superstitious nonsense" and instead using the laws of probability distribution: Step 1: take 1000 or so 20-sided dice. Step 2: Roll each and every one of them ''once''. Step 3: About one-twentieth of these will have rolled 1's. Take these fifty-odd dice, and roll each of them again, ''once''. Step 4: Two or three of these dice will now have rolled 1 twice in a row. Statistically, the odds of rolling the same number three times on a 20-sided die is 1 in 8000, so now these dice have the 1's "rolled out of them"; step 5 is to place them in a special padded container so that they can't roll around, and you may now safely bring them out in emergencies for use for a die roll in which you ''really don't'' want a 1. This is of course patent nonsense; no matter how many times in a row you get a 1, the odds of the ''next'' roll getting a one are always 1 in 20, even if it seems "overdue" for a different one.
** The Random Number God will smite thee, unbeliever.
** [[http://www.darthsanddroids.net/episodes/0195.html This strip]] demonstrates this strategy in action: The prerolled die yields a natural 1 but the {{Random Number God}}'s true believers don't waver. They reason it will simply be ''even more lucky'' next time.
*In the back of the ''{{Hackmaster}} 2nd Edition'' rulebook it actually contains a list of various dice rituals that are prescribed for the game, including rubbing the dice clockwise for higher rolls and counter clockwise for lower rolls.
*In ''{{Knights of the Dinner Table}}'', related to Hackmaster, a character was once beaten to a pulp for touching another gamer's dice. He was blinded by a cupful of soda and then was on the receiving end of a flying tackle. No one (except [[CommanderContrarian Sara]]) thought that this was uncalled for, as "that's one dice squirrel who'll think twice before touching another man's dice!"
** The attacker in that scenario was the 5'3'' pencil-necked Bob Herzog, and the man who touched his dice was the 6'11'' ex-marine Nitro Ferguson, and every time the event is referenced (the fight itself was [[NoodleIncident never shown]]) it is strongly implied that Nitro got hurt AT LEAST as bad as Bob did.
** In the strip, they even outlined a "dice cleansing" ritual, used to banish bad luck from the character's dice.
** Many dice superstitions are explored in this strip. Bob refers to his dice by name, keeps them segregated according to purpose and game genre. Dave refers frequently to having his section of the table "trained" the way he likes it for dice rolling. All of the Knights, even the sensible Sara, have dice rolling styles. But the most infamous incident had Brian and Bob "fame-rubbing" their dice on Gary Jackson's corpse (a "legendary RPG creator" pastiche of Gary Gygax and Steve Jackson) to charge them with good luck. This backfired because Gary, being dead, was obviously out of good luck, and all the fame rubbed dice performed poorly in game play.
* This concept is taken to extremes in ''KingdomOfLoathing'', where the RNG is a conscious entity that has its own account and frequents the various chat rooms. Those who please the RNG in some way may find themselves "Blessed by the RNG", whereas those who annoy it (especially by begging for a blessing) may find themselves "Cursed by the RNG" (both of which are active character effects). Because KoL game mechanics rely heavily on random number generation, and because KoL effects are rarely explicitly defined, there is still a significant debate over whether or not the Blessing and/or Curse actually affect a player's RNG-based "luck" in the game, or if it's just a red herring.
** A player may also be "Blessed by The RNG" by sending a gift package with an 8-ball, and a look in The RNG's display case may reveal other effective sacrifices.
* In the {{Roguelike}} communities which the term originated from, finding a very good item early in the game is a sure sign that the rest of it is going to be a hellish struggle against the wrath of the RandomNumberGod. It's given you your one good thing, now it's going to do its damnedest to kill you.
** The ultimate item in this is an Amulet of Life Saving, which effectively gives you an extra life (in Roguelikes, if you die, that's normally it -- your ([[SaveGameLimits one]]) save game is erased). If you find one of these early, rest assured the game is going to maneuver you into a situation where even instant resurrection will not help you. After all, if something is tough enough to kill you once, it can probably do it a second time... Paradoxically, "lucky finds" like this that should improve your chances of survival will just make players incredibly paranoid and even ''more'' cautious.
** Added as a character in TOME (and it's parent game, zAngband). Random Number Gods are weak, annoying, fast multiplying monsters that drop decent loot -- and cause confusion.
* in some roguelikes, the random number generator is known to get locked into generating the same number repeatedly for an extended period of time more often than probability would suggest it would happen, so seeing a 1.7% chance happen 10 times in a row is not unheard of, especially when you are on the wrong end of it. Ouch.
** Of course, this is normally because, when you're on the ''right'' end of it, you don't need a second chance. ''Your'' critical hits are basically kills, but when [[EverythingIsTryingToKillYou Everything Is Trying To]] [[DeathOfAThousandCuts Nibble You To Death]]...
* Starting characters in {{Angband}} and its offshoots are very dependent on the RandomNumberGod smiling favorably due to the lack of abilities and equipment. Character deaths on the first few floors happen very often, requiring a few do-overs before being able to finally survive.
* A number of bizarre good-luck superstitions have arisen in the {{Warhammer 40000}} community, such as never calling missile launchers by their proper name (it has the word "miss" in it), the idea that painted models are luckier than unpainted models, and the practice of occasionally muttering prayers to the Emperor. Never taken seriously, but often endearing.
**Don't ever say "anything but an x". The more important the roll is, the higher the chance that you will get that x. Most players have lost more games by saying "anything but an x" than by bad strategy.
** Also worth mentioning are the Chaos god's chosen numbers. Chaos players used to get bonuses for fielding units of a certain size based on what god you were using. Slaanesh was 6, Nurgle 7, Khorne 8, Tzeentch 9, [[strike: Malal 11]], the idea being that the Chaos god makes the characters more lucky as long as they spend time in their chosen number. Modern versions of the game, for the sake of simplicity, have removed this rule.
** Never use a dice that has just rolled a good result for a subsequent roll. For example, don't use the dice that just scored hits when rolling to decide wounds. These dice have used up their supply of luck and will not produce good results a second time.
** Ork players are advised to use green dice for standard rolls ("green iz best"), red dice for moving through terrain ("coz da red ones go fasta"), and ("lucky") blue dice for critical rolls. [[TheHorde Buy in bulk]].
** And of course, Tzeentch ''is'' the universe's Random Number God - he is the god of hope, ambition, change, fate and chance. The fact that he happens to be a [[EldritchAbomination Chaos God]] who liberally hands out [[CombatTentacles tentacles]] and [[TheCorruption other mutations]] to his followers both as [[SuperpoweredEvilSide boons]] and [[YouHaveFailedMe punishments]] should tell us something about the [[CrapSackWorld nature of the universe]].
**It is also recomended, as the melta is one of the most powerful anti-armor weapons a troop can carry, that it never be referred to as such, as firing a melta weapon is an exercise in comedic inaccuracy. Simply referring to which model is firing should suffice.
* In the ''{{Discworld}}'' series, trying to worship the Random Number God is a bad idea. The reason is because the Lady never comes to those who say her name - gamblers who tried to worship her directly always seem to die in strange and unlikely (and unlucky) ways. It is said that she has a soft spot for hopeless cases, but relying on this would be a spectacularly bad idea.
** Her temple ''exploded''.
** Plus million-to-one chances come up nine times out of ten...
*** The problem with that is making it an exactly million-to-one chance. No more, no less.
* In the Wuxia RPG Weapons of the Gods, observed good or bad luck with the dice can be utilized as a game effect, discovering that the character is under a curse or blessing which can then be either increased to add actual bonuses or used to create a balancing effect of the opposite type.
* Players of [[MagicTheGathering Magic: The Gathering Online]] revere Grog, Goblin Shuffler.
* We of the ''FinalFantasyTactics'' online simulator Super Tact pay our sacrificed goats to her most revered Random Number Goddess.
* Anyone who has ever played FireEmblem will curse his name. No exceptions.
** In some games, the sequence of random numbers generated after a save is always the same, allowing for a degree of predictability. Proper manipulation of the RNG is key to any Fire Emblem {{Speedrun}}.
*** ''Path of Radiance'' actually features an instance where the RNG can be made to work for you, instead of on his own whims, with the Bonus Experience. Got a character that really needs consistent growths in certain stats? Simply save your game right before giving them the Bonus Experience, the only time when you can consistently a) save your game and b) have a character gain a level without any other factors at play; if you didn't like the stats they gained, no problem! You can reset the game and try again as many times as you want, until the character gets the desired stats.
*** And then ''Radiant Dawn'' allowed ''quick saving'', so you could do this same thing whenever you wanted, in battle! Foolish, Random Number God. Foolish.
* The RNG appears in the browser RPG game BillyVsSNAKEMAN as a monster players in a village (read: clan) can fight (See above image). While all the monsters have accurate hp displays, the RNG has nonsensical numbers or words to represent remaining and total life.
* In ''WorldOfWarcraft'', it's customary to use the /roll command a few times before rolling for a specific piece of equipment to please the RandomNumberGod and to get the low numbers "[[YouFailStatisticsForever out of the way]]". In addition, there are persistent (but frequently debunked) rumors that the game seeds the random number generator according to specific criteria, including (but not limited to) the raid leader, the first person entering the dungeon and/or the number of damage-over-time ([[http://www.youtube.com/watch?v=HtvIYRrgZ04 more dots!]]) spells on the boss.
** That's ridiculous. Everyone knows that the dice will only favor you if you a) contributed the least of anyone to the party/raid, b) can't use or shouldn't be using the item in question or c) have someone else present who has waited for the random drop for months. These effects are cumulative, and if all three are true you're almost guaranteed to win. The RandomNumberGod of WoW is a sadistic bastard.
* In ''GodsDebris'', GodIsDead, having killed Himself at the moment of the Big Bang. However, He left behind matter ("God-Dust") and probability. Said probability determines how matter moves and evolves, effectively being the RandomNumberGod. Despite its seeming randomness, the probability's final goal is [[spoiler:God's complete reassembly]].

[[foldercontrol]]

[[folder: Real Life ]]

* There are some calculations scientists perform that require truly random numbers, such that the slight predictability inherent in a computerised system is too large. For these cases a "True Random Number" generator can be purchased, which is effectively a small radio telescope tuned precisely to the frequency of the Cosmic Microwave Background radiation, as produced by the Big Bang.
** Radioactive isotopes can also be used - set up a Geiger counter and a numeric counter, then stop the counter whenever the Geiger meter goes "beep". The time between successive radioactive decays is random, so your numbers are random.
*** http://www.fourmilab.ch/hotbits/ serves up fresh hot discarded random bits on demand, using radioactive decay.
** Noisy diodes are also truly random, and as a benefit for computers, binary.
** http://www.random.org/ generates random numbers using atmospheric noise.
* As [[http://www.youtube.com/watch?v=bR2fxoNHIuU&eurl=http://grognardia.blogspot.com/2008_11_01_archive.html this]] video explains, cheap dice have dull edges because they were polished in a rock tumbler. The resulting imperfections change the die's center of gravity and make it easier to roll over some edges than others. So there is a scientific explanation to this phenomenon, and a way to prevent it.
** It also makes reference to one of the classic ways con artists can rig games: "shaving" the edges on a die (usually a casino die, since they have sharp edges to begin with). You trim off a tiny bit on the edges of whatever's opposite the side you don't want to land on. So for example, if you don't want to roll a six, you'd shave the edges of the one face. The die expends less energy rolling over the shaved edges, which skews the probability ''way'' below 1/6. (Incidentally, if you find an ''actual'' casino die that's been shaved, you could be rewarded by the state gaming commission. They take fair odds seriously. Outside of a casino, though... just remember the page quote.)
**Another common method of messing with die odds is to cook them. You take your plastic die, put it in the microwave with the side you wan to show face up, then nuke it for a couple of seconds, no more than five. The nuking causes the plastic to melt downwards a bit(thus making the die more likely to stop on that edge, since it's heavier). Done right, it's almost undetectable at casual inspection.
* Most people will have various superstitions about dice, such has keeping them in a special place before use, blowing on them (which comes from an ancient form of cheating, keeping heat-activated wax inside the die) which is now supposed to bring luck. There are as many rituals for luck based games as there are people, sometimes more. Of course, unless you are cheating, this has [[YouFailStatisticsForever absolutely no effect]].
*''{{Suikoden}}'' has trouble with this at times. There's a cup shuffling game where the dealer always follows a specific pattern, every time you quit and play. However, there's another game that involves throwing three dice. Despite the fact that the odds of getting very good rolls (three of the same number, except one, or 4,5,6) or very bad rolls (all 1's or 1,2,3) should be low, you'll find that you and the computer will get these combinations very frequently. Murphy's Law of course will turn what should be a 1/216 chance into 1/3. Also a ground rule is that you must roll something valid in three turns (i.e., you automatically lose if you roll three "no scores"), the computer will always roll something valid on the third turn (even if it's one of the dice going out of bounds).
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