d63

A d63 is a die designed to produce a value from 1 to 63 with equal probability. In tabletop gaming, it is a nonstandard die; mainstream sets commonly include d4, d6, d8, d10, d12, and d20, with some games also using d30 or d100. A 63-sided die is not a typical fixture because there is no well-known regular polyhedron with exactly 63 faces. As a result, commercially available d63s are usually irregular polyhedra or novelty items, and their fairness can be less reliable than that of standard dice.

Manufacturing and fairness considerations are important for a d63. Irregular shapes can introduce bias if not manufactured with precise symmetry and balancing. Some producers label an irregular 63-faced die and test it for approximate uniformity, but outcomes may still deviate from perfect equality compared with standard dice.

In practice, players who want a 63-valued outcome often simulate a d63 using other tools. A common method is to roll a d64 and reroll if the result is 64, yielding a uniform 1–63 distribution. Alternatively, digital dice rollers can generate a random number in the 1–63 range, or players may map results from two or more standard dice to the 1–63 interval, though careful mapping is required to avoid unintended bias.

Use cases for a d63 tend to be limited to homebrew systems or probability demonstrations. For many players, simulating a d63 with standard dice or digital tools remains the practical approach. See also: dice, polyhedron, random number generation.

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