One-Roll Engine

The One-Roll Engine (or O.R.E.) is a generic role-playing game system developed by Greg Stolze for the alternate history superhero roleplaying game Godlike. The system was expanded upon in the modern-day sequel, Wild Talents, as well as the heroic fantasy game Reign and the free horror game Nemesis. A simpler version was used for Monsters and Other Childish Things. The One-Roll Engine is notable for its unique dice rolling system in which matched values on ten-sided dice (d10s) determine all variables of a check in a single roll. This eliminates, for example, the separate initiative, hit location and damage rolls common during combat in other systems.

The One-Roll Engine uses a dice pool of d10s equal to the character's Stat and Skill similar to that used by Storyteller system. Since the dice are always d10s, a pool is written as the number of dice followed by a "d"; for example, a pool of six dice would be written "6d".

While most dice pool systems count the number of dice which roll above a certain number to determine success, the O.R.E. system instead depends on matching dice, such as a pair of dice showing 8 or three dice showing 2. Matching dice are called a "set"; the number of matching dice in a set is called the "Width", while the face up number on the dice is the set's "Height". Shorthand notation for writing results is Width x Height, so a pair of 8s would be written 2x8 and three 2s would be written 3x2.

A roll may have more than one set; the player can usually choose which one to use. If there are no matches, then the player may select a single die to act as a set with a Width of 1. In general, a set's Width determines the speed of an action, while the Height determines how successful the action was. In combat, Width and Height also determine the damage and hit location.

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