Dice

(singular die or ) are small, throwable objects with marked sides that can rest in multiple positions. They are used for generating, commonly as part of s, including , s, s, and.

A traditional die is a with each of its six faces marked with a different number of dots  from one to six. When thrown or rolled, the die comes to rest showing a random from one to six on its upper surface, with each value being equally likely. Dice may also have or irregular shapes and may have faces marked with numerals or symbols instead of pips. Loaded dice (see below) are designed to favor some results over others for or entertainment.

History
Dice have been used since before recorded history, and it is uncertain where they originated. It is theorized that dice developed from the practice of fortune-telling with the of hoofed animals, colloquially known as. The game of  was played with flat two-sided throwsticks which indicated the number of squares a player could move, and thus functioned as a form of dice. Senet was played before 3000 BC and up to the 2nd century AD. Bone dice from, Scotland have been dated to 3100–2400 BC. Excavations from graves at , an settlement, unearthed  dice dating to 2500–1900 BC.

Games involving dice are mentioned in the ', , ' and. There are several references to “casting lots” (יפילו גורל yappîlū ḡōrāl), as in  22, indicating that dicing (or a related activity) was commonplace when the psalm was composed. Knucklebones was a played in ; a derivative form had the four sides of bones receive different values like modern dice.

Although gambling was illegal, many were passionate gamblers who enjoyed dicing, which was known as aleam ludere (“to play at dice”). There were two sizes of Roman dice. Tali were large dice inscribed with one, three, four, and six on four sides. Tesserae were smaller dice with sides numbered from one to six. Twenty-sided dice date back to the 2nd century AD and from as early as the 2nd century BC.

and s originated in China as developments from dice. The transition from dice to playing cards occurred in China around the (618–907 AD), and coincides with the technological transition from rolls of manuscripts to  books. In Japan, dice were used to play a popular game called. There are two types of sugoroku. Ban-sugoroku is similar to and dates to the  (794–1185), while e-sugoroku is a.

Use
Dice are thrown onto a surface either from the hand or from a container designed for this (such as a cup or tray). The face of the die that is uppermost when it comes to rest provides the value of the throw.

The result of a die roll is determined by the way it is thrown, according to the laws of. A die roll is made by uncertainty in minor factors such as tiny movements in the thrower's hand; they are thus a crude form of.

One typical contemporary is, where two dice are thrown simultaneously and wagers are made on the total value of the two dice. Dice are frequently used to introduce randomness into s, where they are often used to decide the distance through which a piece will move along the board (as in and ).

Arrangement
Common dice are small s, most often 1.6 cm across, whose faces are numbered from one to six, usually by patterns of round dots called. (While the use of is occasionally seen, such dice are less common.)

Opposite sides of a modern die traditionally add up to seven, requiring the 1, 2, and 3 faces to share a. The faces of a die may be placed about this vertex. If the 1, 2, and 3 faces run counterclockwise, the die is called “right-handed”. If those faces run clockwise, the die is called “left-handed”. Western dice are normally right-handed, and Chinese dice are normally left-handed.



The pips on standard six-sided dice are arranged in specific patterns as shown. Asian style dice bear similar patterns to Western ones, but the pips are closer to the center of the face; in addition, the pips are differently sized on Asian style dice, and the pips are colored red on the 1 and 4 sides. Red fours may be of Indian origin.

Manufacturing
Non-precision dice are manufactured via the plastic process, often made of. The pips or numbers on the die are a part of the mold. Different pigments can be added to the dice to make them opaque or transparent, or multiple pigments may be added to make the dice speckled or marbled.

The coloring for numbering is achieved by submerging the die entirely in paint, which is allowed to dry. The die is then polished via a process similar to. The scrapes off all of the paint except for the indents of the numbering. A finer abrasive is then used to polish the die. This process also produces the smoother, rounded edges on the dice.

Precision casino dice may have a polished or sand finish, making them transparent or translucent respectively. Casino dice have their pips drilled, then filled flush with a paint of the same as the material used for the dice, such that the center of gravity of the dice is as close to the geometric center as possible. This mitigates concerns that the pips will cause a small bias. All such dice are stamped with a to prevent potential cheaters from substituting a die. Precision backgammon dice are made the same way; they tend to be slightly smaller and have rounded corners and edges, to allow better movement inside the dice cup and stop forceful rolls from damaging the playing surface.

Etymology and terms
The word die comes from dé; from  datum “something which is given or played”.

While the terms , deuce, trey, cater, cinque and sice are generally obsolete, with the names of the numbers preferred, they are still used by some professional gamblers to designate different sides of the dice. Ace is from the Latin as, meaning “a unit”; the others are 2 to 6 in.

When rolling two dice, certain combinations have slang names. The term snake eyes is a roll of one on each die. The  traces use of the term as far back as 1919. The US term boxcars, also known as midnight, is a roll of six pips on each die. The pair of six pips resembles a pair of s on a freight train. Many rolls have.

Unicode representation
Using Unicode characters, the faces ⚀ ⚁ ⚂ ⚃ ⚄ ⚅ can be shown in text using the range U+2680 to U+2685 or using decimal  to.

Loaded dice
A loaded, weighted, cheat, or crooked die is one that has been tampered with so that it will land with a specific side facing upwards more or less often than a fair die would. There are several methods for making loaded dice, including rounded faces, off-square faces, and weights. Casinos and gambling halls frequently use transparent dice as tampering is easier to detect than with opaque dice.

Polyhedral dice
Various shapes like two-sided or four-sided dice are documented in archaeological findings; for example, from Ancient Egypt and the Middle East. While the cubical six-sided die became the most common type in many parts of the world, other shapes were always known, like 20-sided dice in Ptolemaic and Roman times.

The modern tradition of using sets of polyhedral dice started around the end of the 1960s when non-cubical dice became popular among players of, and since have been employed extensively in role-playing games and. Dice using both the numerals 6 and 9, which are reciprocally symmetric through rotation, typically distinguish them with a dot or underline.

Common variations
Dice are often sold in sets, matching in color, of six different shapes. Five of the dice are shaped like the s, whose faces are s. Aside from the cube, the other four Platonic solids have 4, 8, 12, and 20 faces, allowing for those number ranges to be generated. The only other common non-cubical die is the 10-sided die, a die, whose faces are ten, each with two different edge lengths, three different angles, and two different kinds of vertices. Such sets frequently include a second 10-sided die either of contrasting color or numbered by tens, allowing the pair of 10-sided dice to be combined to generate numbers between 1 and 100.

Using these dice in various ways, games can closely approximate a variety of s. For instance, 10-sided dice can be rolled in pairs to produce a of random percentages, and summing the values of multiple dice will produce approximations to s.

Unlike other common dice, a does not have a side that faces upward when it is at rest on a surface, so it must be read in a different way. On some four-sided dice, each face features multiple numbers, with the same number printed near each vertex on all sides. In this case, the number around the vertex pointing up is used. Alternatively, the numbers on a tetrahedral die can be placed at the middles of the edges, in which case the numbers around the base are used.

Normally, the faces on a die will be placed so opposite faces will add up to one more than the number of faces. (This is not possible with 4-sided dice and dice with an odd-number of faces.) Some dice, such as those with 10 sides, are usually numbered sequentially beginning with 0, in which case the opposite faces will add to one less than the number of faces.

Some twenty-sided dice have a different arrangement used for the purpose of keeping track of an integer that counts down, such as health points. These spindown dice are arranged such that adjacent integers appear on adjacent faces, allowing the user to easily find the next lower number. They are commonly used with collectible card games.

Rarer variations
“Uniform fair dice” are dice where all faces have equal probability of outcome due to the symmetry of the die as it is. Theoretically, these include:


 * s, the duals of the infinite set of, with triangle faces: any multiple of 4 (so that a face will face up) above 8
 * s, the of the 13 s: 12, 24, 30, 48, 60, 120 sides
 * s, an infinite set of tetrahedra made from congruent non-regular triangles: 4 sides. This is a less symmetric tetrahedron than the Platonic tetrahedron, but still sufficiently symmetrical to be face-transitive. Similarly, and s are less symmetrical but still face-transitive dodecahedra: 12 sides.
 * s, the five regular polyhedra: 4, 6, 8, 12, 20 sides
 * , the duals of the infinite set of s, with kite faces: any even number not divisible by 4 (so that a face will face up) above 6

Two other types of polyhedra are technically not face-transitive, but are still fair dice due to symmetry:


 * s: the basis of
 * s: the basis of long dice and teetotums

and s can in principle be made with any number of faces, including odd numbers. Long dice are based on the infinite set of. All the rectangular faces are mutually face-transitive, so they are equally probable. The two ends of the prism may be rounded or capped with a pyramid, designed so that the die cannot rest on those faces. 4-sided long dice are easier to roll than tetrahedra, and are used in the traditional board games and.

Non-numeric dice
The faces of most dice are labelled using sequences of whole numbers, usually starting at one, expressed with either pips or digits. However, there are some applications that require results other than numbers. Examples include letters for, directions for , , playing card symbols for , and instructions for sexual acts using.

Alternatively-numbered dice
Dice may have numbers that do not form a counting sequence starting at one. One variation on the standard die is known as the “average” die. These are six-sided dice with sides numbered, which have the same  as a standard die (3.5 for a single die, 7 for a pair of dice), but have a narrower range of possible values (2 through 5 for one, 4 through 10 for a pair). They are used in some table-top, where a narrower range of numbers is required. Other numbered variations include and.

Spherical dice
A die can be constructed in the shape of a sphere, with the addition of an internal cavity in the shape of the of the desired die shape and an internal weight. The weight will settle in one of the points of the internal cavity, causing it to settle with one of the numbers uppermost. For instance, a sphere with an octahedral cavity and a small internal weight will settle with one of the 6 points of the cavity held downwards by the weight.

Applications
Polyhedral dice are commonly used in role-playing games. The fantasy role-playing game Dungeons & Dragons (D&D) is largely credited with popularizing dice in such games. Some games use only one type, like  which uses only ten-sided dice. Others use numerous types for different game purposes, such as D&D, which makes use of all common polyhedral dice. Dice are usually used to determine the outcome of events. Games typically determine results either as a total on one or more dice above or below a fixed number, or a certain number of rolls above a certain number on one or more dice. Due to circumstances or character skill, the initial roll may have a number added to or subtracted from the final result, or have the player roll extra or fewer dice. To keep track of rolls easily, dice notation is frequently used.

Many board games use dice to randomize how far pieces move or to settle conflicts. Typically, this has meant that rolling higher numbers is better. Some games, such as , have inverted this system by making the lower values more potent. In the modern age, a few games and game designers have approached dice in a different way by making each side of the die similarly valuable. In , players spend their dice to take actions based on the die’s value. In this game, a six is not better than a one, or vice versa. In ' (and its descendant, '), different sides of the dice can offer completely different abilities. Several sides often give resources while others grant the player useful actions.

Dice can be used for divination and using dice for such a purpose is called. A pair of common dice is usual, though other forms of polyhedra can be used. Tibetan Buddhists sometimes use this. It is highly likely that the used the  as dice. They referred to such dice as “the dice of the gods” and they sought to understand the universe through an understanding of geometry in polyhedra.

Astrological dice are a specialized set of three 12-sided dice for divination; the first die represents the planets, the Sun, the Moon, and the of the Moon, the second die represents the 12 zodiac signs, and the third represents the 12 houses. A specialized icosahedron die provides the answers of the, conventionally used to provide answers to yes-or-no questions.

Dice can be used to generate random numbers for use in s and applications. The describes a method by which dice can be used to generate s.  is a method recommended for generating secure but memorable passphrases, by repeatedly rolling five dice and picking the corresponding word from a pre-generated list.

Notation
In many gaming contexts, especially tabletop role-playing games, shorthand notations representing different dice rolls are used. A “d” or “D” is used to indicate a die with a specific number of sides; for example, denotes a four-sided die. If several dice of the same type are to be rolled, this is indicated by a leading number specifying the number of dice. Hence, means the player should roll six eight-sided dice and add the results. Modifiers to a die roll can also be indicated as desired. For example,  instructs the player to roll three six-sided dice, calculate the total, and add four to it.

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