decaster

A decaster is a hypothetical ten-sided die. Unlike more common dice such as the six-sided cube or the twenty-sided icosahedron, a decaster is not a regular polyhedron. Its faces are typically numbered from 0 to 9 or 1 to 10. Decasters are often used in games where a random number within a range of ten is required, such as in some role-playing games or board games.

There are a few common designs for decasters. One is a ten-sided prism with two pentagonal bases and ten rectangular sides. Another, more spherical design, resembles a sphenocorona, a polyhedron with 20 faces, but with the faces slightly modified to create ten equally likely outcomes. Some decasters are also created by shaping a standard die, like a d10, to have ten faces. The distribution of probabilities for each face to land uppermost is crucial for fair gameplay. Manufacturers ensure that each face has an equal chance of being rolled. Decasters are a useful tool for introducing probability and chance into various forms of entertainment.