And there is an issue.
A recap to understand my next point.
Mongoose has released open content for a RPG using d100 mechanics in three products.
- The Runequest System Reference Document. 2006
- D100 II System Reference Document, 2011
- Legend Core Rulebook, 2011
In the Open Game License Section 7 reads
7. Use of Product Identity: You agree not to Use any Product Identity, including as an indication as to compatibility, except as expressly licensed in another, independent Agreement with the owner of each element of that Product Identity.
You agree not to indicate compatibility or co-adaptability with any Trademark or Registered Trademark in conjunction with a work containing Open Game Content except as expressly licensed in another, independent Agreement with the owner of such Trademark or Registered Trademark. The use of any Product Identity in Open Game Content does not constitute a challenge to the ownership of that Product Identity. The owner of any Product Identity used in Open Game Content shall retain all rights, title and interest in and to that Product Identity.
Per section 7 not only you can't cite compatibility with a trademark, since trademark are also consider product identity, a strict interpretation means you can't use the trademark as part of the text. Since Mongoose lost their license to the trademark Runequest they can't grant a license to use it as part of open content.
The Runequest System Reference Document
Fails the compatibility test by having Runequest as part of the title, and fails the use of product identity test by referencing Runequest numerous times in the text.
The D100 II System Reference Document
Does not mention Runequest at all until Section 15. Which also the very last bit of text in the SRD. D100 II SRD cites three release by Mongoose. The Runequest System Reference Document, the Runequest Companion System Reference Document, and the Runequest Monsters System Reference.
Shades of Gray vs Crystal Clear
The reason to make this distinction is that if you want to publish something using open content without the advice of attorney then the open content has to be crystal clear. A major point of the OGL is make it easy for people to understand they are allowed to use.
The first SRD, the Runequest System Reference Document, clearly has issues in whether it crystal clear to use it open content. The second one, the D100 II System Reference Document, was a lot harder a call on. It Section 15 "using Product Identity or citing compatibility" as Section 7 state?
The common sense answer is doesn't violate either provisions. There is an issue that the presence of the three citations means that the open content of the D100 II SRD is based on part on the open content of three documents that Mongoose no longer has the license to give permission to use. Thus tainting the open content of the D100 II SRD despite it not using any of Runequest or Glorantha IP and being Mongoose's original work.
However luckily for fans of D100 RPGs, the open content of Legends has none of the above issues. And with the core rulebook having been expanded with the open content of the "Legend of" series, you are not missing out on anything found in
Gore and OpenQuest
The Gore RPG by Dan Proctor along with OpenQuest and OpenQuest II by Net Newport both cite one or more of the Runequest SRDs. In the long run they may to be fixed by only using the open content of the Legend RPG.
Wrapping it up
Upon reflection, if I was in Chaosium shoes I would have an issue with the original Runequest System Reference Document. Trademarks are valuable and with it being part of the title in the text would cause numerous issues with dealing with third parties.
I think complaining or taking legal action is going out on a limb with the D100 II SRD. Runequest not referenced in the title or the main body of the text. The only part where Runequest makes an appearance is in Section 15. Going after folks that used the D100 II SRD just make Chaosium look like bullies.
I recommend for future projects based on the D100 mechanics is to use the open content of the Legend Core Rulebook, and to the various Legend of line for additional content. That way it is crystal clear.
If you have any doubts then please consult an IP attorney. However just be aware you may have to walk them through what open content and what open content licenses are. IP attorneys first instinct is to give advice that either protect your material to greatest extent allowed by law, or to protect from any possibility of lawsuits.
The key question I found to be useful is "This is my understanding of what this means, and this is what I want to do. I am correct? Or am I missing something?". I consulted with an attorney prior to publishing as Bat in the Attic Games as I was starting out as a licensee of Judges Guild and also using the open content of Swords and Wizardry