Discussing the Open Gaming License

Poor Clarity of Open Game Content Sucks; And Doubly so for the Aggressive Product Identity Declarations

and , I was talking with a few people on Mastodon about the Open Game License (OGL 🔍).

Before I go into that, I want to layout my understanding of copyright as it applies to Role Playing Games (RPGs 🔍). And please don’t take this as legal advice.

The OGL appears to have partially come about in part due to the court case TSR, Inc. v. Mayfair Games, Inc., 1993 WL 79272 (N.D. Ill.).

The gist of that case is that the specific words used to describe the mechanics may be protected by copyright, however the underlying mechanics are not; Note, they could be Trademarked or Patented, like Magic the Gathering’s “Tap” concept/symbol.

By creating the OGL and System Reference Document (SRD 🔍), we have clear instructions on how to share the game mechanics and the language used to describe those mechanics.

In other words, once something is released under the OGL, I continue to have a right to share the developments I make against that common document.

Back to the Conversation

On Mastodon, we were sharing our observations and frustrations with the OGL; Namely the bad, lazy, or aggressive demarcation tactics of Product Identity (PI 🔍) and Open Game Content (OGC 🔍).

Alex Schroeder pulled up a post from , and it is just as relevant today.

I’m not happy with the Open Gaming License (OGL). What frustrates me the most are greedy publishers who declare everything important to be Product Identity.

I wanted to set up a wiki for fan generated content based on Necromancer Games’ book Bard’s Gate. To my surprise, I found the exact wording of the license precluded the reuse of anything important. That’s when I realized that the OGL can be cool, but it often isn’t. Unfortunately, the D&D 3.5 SRD came with the OGL and that’s why we are stuck with it.

No wonder the Bard’s Gate fan site promised in the book never materialized. The lock down certainly worked. The book has basically disappeared from our memory. I still have an archive of the wiki I started back then. Maybe I’ll get to use it in ninety years. Right.

Alex also cites one of his posts regarding Old School Fanzines:

Another thing of note is that Knockspell uses the Open Gaming License whereas Fight On provides no license for its readers. Unfortunately, many of the Knockspell articles will say This article contains no Open Game Content other than spell names, magic item names, and terminology derived from the game rules or The rules described in this article are Open Game Content, and the remainder is Product Identity, thereby negating the benefit to readers.

And Sandra shared, among other things, the following:

The product identity is a huge flaw in the OGL that some publishers try to abuse and others treat responsibly.

Please stop using the Product Identity clause to lock down your mechanics, new spells, feats, etc. It telegraphs to me that your contributions come with some kind of “strings attached”. Maybe you want to “protect” your cool idea, but want the ready made market of a larger ecosystem? I don’t know, but it smells fishy.

The State of the Open Game License

I’ve written about the OGL before:

When Wizards of the Coast (WotC 🔍) released Dungeons and Dragons: Fourth Edition (4E 🔍) they didn’t have a clear license. They tightened the licensing with their 4E Game System License. Few publishers rallied to this new banner, in part because it was far more limiting.

It is during this time that Pathfinder rose as the heir apparent to Dungeons and Dragons: Third Edition (3E 🔍) and the Old School Renaissance (OSR 🔍) begins churning out retro-clones and systems that feel a lot like pre-3E systems.

Forward to the release of Dungeons and Dragons: Fifth Edition (5E 🔍). WotC releases the System Reference Document: Fifth Edition (SRD5 🔍) using the familiar OGL. They even open up licensing to publish content using their PI.

The DM’s Guild program allows broader usage of WotC’s content.

How is Dungeon Masters Guild different from the Open Game License (OGL)?

The Open Game License and the Dungeon Masters Guild are two distinct and separate things.

Under the DMs Guild program, you can publish D&D material that has no setting or uses the Forgotten Realms, Ravenloft, Eberron or Ravnica settings.

Under the Open Game License, you can typically publish material that has no setting or uses your own original setting.

When you publish material that has no setting, then publishing under the DMs Guild program allows you to use the entire D&D 5th edition rules, not just the subset found in the SRD. It also allows you to sell the material here on the DMsGuild.com marketplace.

By all accounts 5E is successful; Many 3rd parties are developing content under OGL and for the DM’s Guild. But things remain less than ideal around people’s implementation of the OGL.

What to Do?

Again, I am not a lawyer, and this is not legal advice.

If you want to make a game that derives from an SRD or content released via the OGL do the following:

Read the License a few times. It’s not that long and you’re using that license and agreeing to its contraints.

Update Section 15 of the license you include in your work. This means including the Section 15 contents of all the works you referenced. You should also add your work’s copyright statement to that section. This is the easiest part. Failure to do so is a hard pass on your product.

Clearly identify what is Open Game Content and what is Product Identity. There’s a lot of wiggle in “clearly identify”, and I’ve seen quite a few works fail to be clear about what is or isn’t Product Identity. And some works are downright aggressive in defining Product Identity such that no one who reads this declaration would ever want to use any of the Open Game Content that may (or may not) be in that work.

When I am looking at game products that include the OGL, I see far too many failures to do at least one of the above.

Some products aggressively use OGC then cast misdirection on what they’re adding, if anything. I’m looking at the now defunct Adventures in Middle-Earth product line as an egregious example; But that’s also comingled with the Tolkien Estate.

What I Hope You Do?

Be explicit and precise in what you declare as Product Identity and/or Open Game Content. What do I mean by that?

On my site, I declare open game content as follows:


Ray of Wounding (3rd-level necromancy)…

Ray of Wounding

3rd-level necromancy

Casting Time: 1 action
Range: 60 feet
Components: V,S
Duration: Concentration, up to 1 minute

A violet beam of enervating energy springs from your finger toward a creature within range. Make a ranged spell attack against the target. On a hit, the target gains the condition.

At the end of each of the target’s turns, it can make a Constitution saving throw against the spell. On a success, the spell ends. When the spell ends, the target loses the wounded condition.

At Higher Levels: When you cast this spell using a spell slot of 4th level or higher, the spell creates one more ray for each slot level above 3rd level. You can direct the beams at the same target or at different ones. Make a separate attack roll for each beam.

Note: Add Word of Wounding to the Sorcerer, Warlock, and Wizard spell lists.


I have clearly marked what I am releasing as Open Game Content. Structured markup makes this easy.

Were I releasing a printed book, I’d organize the content into chapters. I would want any chapter that declares and describes OGC to only contain OGC. The other chapters would have product identity and could contain references to those OGC declarations. I would then state which chapters had explicit OGC.

Another thing to consider is releasing the content without product identity.

In my campaign, I might refer to it as “Brother Calvin’s Ray of Wounding.” If I am released a setting book with that spell, I’d declare “Brother Calvin” as Product Identity.

WotC used this approach in SRD5’s spell “Magnificent Mansion”. In WotC books, they attribute that spell to a named personna. However, in the SRD5, they released only a general name. The personna remains protected yet others can build on the specifics of that spell.


We live in an abundance of game mechanics and rules. In the 20 years since , we’ve seen a broadening of game material readily available to repurpose and extend.

I take it to be self-evident that those that don’t contribute to the commons (via the OGL or similar licenses) will find lower adoption of their products. And that those products will wither once the initial champion moves on. I’m not seeing much 4E related content these days. But I am seeing lots of 3E compatable content.

Gaming is about sharing a creative endeavor with people around your table (or Zoom meeting). If you are crafting mechanics or spells or what not, consider sharing those mechanics in a way that others may clearly build from them.

And if you are publishing material that uses Open Game Content, be a better player at that table. Be explicit in what you are releasing as Open Game Content and be explicit in what you are protected as Product Identity (list the nouns, name the chapters, etc.).

Post Script

Lately, I’ve been showering a lot of love on Stars without Number: Revised Edition 🔍 and Worlds without Number 🔍. And I wish there were an SRD for this game. It’s something that someone could extract; It’s super close to an OSR system. And what would I want in that SRD?

Character creation rules, the game systems, and the faction turns. The tags and plethora of random tables could remain closed off (as product identity). It’s the core of that system that I want to see free for others to use and re-purpose.

To Sine Nomine’s credit, they release free content. The copyright owner is clear about what you can do with it (if you ask him). And he doesn’t feign an Open Game by grabbing Open Game Content, adding his own things, and then being murky about what is or isn’t Open Game Content.