One Roll Engine

One Roll Engine, abreviated as ORE is a fairly generic roleplaying system that has been adapted for various settings and games, the most recent and notable adaptation has been the Reign RPG.

ORE uses pools of dice combined from inborn abilities and learned skills, much like the more well-known World of Darkness (Storyteller) mechanic. However, once the dice are rolled you do not look for sucesses, or specific numbers or add their results together as in most systems, you look for "sets", that is, groups of dice that show the same number. For example if you roll 7, 4, 9, 7, 4 and 4, you have three sets a one 9 set, a double 7 and a set of three fours. You pick one of these sets as the result of your roll.

In this way a single roll (that's why it's called ORE) conveys two bits of information, the "width" of the roll (how many dice are there in the set and the "height" - the value of the dice in the set. In combat this shows the strength and the location of the hit, when using a skill this information tells you the quality and the speed of your work etc.

This core mechanic is then expanded with various special dice (different games treat these in different ways) such as Master dice. These specials let you set them to a specific number before you roll, or change them after you roll and so on.