Numerous Judges Guild products were marketed as "A Judges Guild Universal Fantasy Supplement". These products were system agnostic and intended to be usable with any then-current fantasy roleplaying game system. To support rapid, easy, and consistent use across a variety of systems, Judges Guild developed and used a "Universal Fantasy" format of development and presentation.
Generally speaking, this format emphasized the design commonalities of early versions of Dungeons & Dragons, RuneQuest, and Tunnels & Trolls, while minimizing their distinctiveness. The resulting presentation may appear at first to be a new or unique game system, but it never was intended to be usable on its own. The format developed through time, but even in its final state it was not a complete game system. Rather, it is a comprehensive notation system used to present scenarios and sources in a standardized, but system agnostic, fantasy format.
The "Universal Format" was especially commonly used during the early 1980s.
N.B. The "Universal Format" should not be confused with Field Guide to Encounters.