Open gaming developed in 2000 from Wizards of the Coast's Open Gaming License, which the company applied to its d20 System used at the core of the Dungeons & Dragons role-playing game. Because its heritage is intertwined with the most successful RPG, "open gaming" often refers to the d20 System, but other open systems and licenses have been developed as well.
The initiative for an open license on rules resulted from the many unique sets of rules used by RPGs. To ease the designer's development process and the player's learning process, major RPG developers created generic role-playing game systems, such as Steve Jackson Games' GURPS, for use in the design of their own games. Wizards of the Coast took the idea a step further by making the core rules system free (as in speech and beer) so that game designers could produce games under the d20 umbrella of rules and so that players need not make any purchases in order to learn the core rules. Among other things, game developers believe that this drive will make their games more accessible and that it could further channel the popularity of the RPG industry towards Dungeons & Dragons.
Several game designers criticized the Open Gaming License for not being as open as it could be and for being controlled by the RPG market leader Wizards of the Coast. Some of these critics wrote their own open licenses. Lately, drafting new open gaming licenses has waned slightly as it becomes apparent that numerous copyleft-style licenses that could be applied to game rules already exist, such as the GNU Free Documentation License. One open gaming license similar to the GFDL, the October Open Game License, has already been deprecated in favor of a Creative Commons License.History
Emergence from the Open Gaming License