The Open Gaming Foundation believes that a license must provide for two important features in order to be an Open Game license.
1. The license must allow game rules and materials that use game rules to
be freely copied, modified and distributed.
2. The license must ensure that material distributed using the license cannot have those permissions restricted in the future.
The first requirement precludes an Open Gaming License from placing any limitation on the licensed content beyond those necessary to enforce the terms of the license itself. This prohibition includes a restriction against commercial distribution, a requirement for review or approval, the payment of a fee of any kind to a 3rd party, or any other term that would seek to limit the free use of the licensed material.
The second requirement means that the license must have a mechanism to ensure that the rights it grants cannot be taken away, either by the original contributor of the material, of the copyright holder of the license text itself, by an action taken on behalf of a 3rd party, or any other process.
The Open Gaming Foundation is aware of several licenses which it believes meet these requirements. The Foundation makes no representation or warranty as to the fitness or actual terms of any of these licenses. The following list of licenses is provided as a convenience and should not be taken as a formal endorsement of the terms of any of these licenses.
If you are aware of any additional licenses that should qualify for this list, or if you have concerns about any of these listed licenses, please let the Foundation know.
Known Open Gaming Licenses:The Open Gaming License drafted by Wizards of the Coast