D6

D6, or six-sided die, is the most common form of dice used in games and probability experiments. It is typically a cube with six faces, each face marked with a number of pips from one to six. In many standard dice, opposite faces sum to seven (1 opposite 6, 2 opposite 5, 3 opposite 4).

Construction and variants: Most contemporary D6 dice are made of plastic, but can also be metal, wood, or resin. The standard size for many board games and role-playing games is about 16 millimeters along each edge; other sizes range from roughly 12 to 20 mm. Pips or numerals can be engraved or painted; some dice are transparent, colored, or decorative. Fairness assumes the die is well balanced; loaded or mismanufactured dice can be biased.

Properties and notation: A fair D6 has equal probability for each face, 1/6. The uniform distribution yields a mean of 3.5 and a variance of 35/12 ≈ 2.92. In dice notation used in tabletop gaming, "d6" denotes a six-sided die, and expressions like "1d6" or "3d6" indicate rolling one or three such dice and summing their results.

Uses and history: D6s are widely used in board games, party games, and many role-playing game systems for determining outcomes, damage, or random events. They are also used in education to teach probability and statistics. The concept of dice is ancient, but the standard D6 remains the most recognizable form of dice in modern gaming.