System 1/2 (one-half) is a lightweight roleplaying game system meant for one-shot and pickup games. Everything here is a very boiled down form of SystemTWO. The ruleset has easy to use rules for handling chance using dice, and focuses on narrative driven play. While not solely dependent on improvisation, it also relies heavily on that play method.
One player called the narrator sort of manages the overall narrative, while one or more other players each create and play characters in that fiction. It calls upon many gaming systems that have come before, but addresses some of the ideas of play in new and creative ways. For example, the game is considered a narrative told by the narrator first and foremost, with the players with characters enriching the detail of that narrative when cued.
Here are the rules for the game, broken down into small digestible sections. You can start playing just after reading the first two sections, but the narrator should ready the additional in-depth pages so they can get a deeper understanding of the way things are meant to work.
These are the two core sets of rules:
These are in-depth looks into the various parts: