Dungeons & Dragons has some of the weirdest, most inconsistent approaches to how it defines its new editions.

There are very few games that have changed that much over the years, but the number of changes aren’t quite reflected in the edition numbering. It doesn’t help that there were two different strands of D&D for a decade.

Changes in the game have been big and small. For the period of 1974-1999, we saw the following “editions” of the game:

• Original Dungeons & Dragons
• Basic Dungeons & Dragons (Holmes)
• Advanced Dungeons & Dragons (1E)
• Dungeons & Dragons: Basic, and Expert sets (Moldvay and Cook)
• Dungeons & Dragons: Basic, Expert, Companion, Masters, and Immortal sets (Mentzer)
• Advanced Dungeons & Dragons (2E)
• Dungeons & Dragons: Rules Cyclopedia (Aaron Allston)

All of those editions shared the basic mathematical underpinnings, although they could have wildly different character powers – especially at the higher levels of the game. But it was not uncommon for an AD&D DM to use a Basic D&D adventure at their table.

Things changed up greatly later. The next edition (3E) completely redid the game, changing all the procedures and mathematics that underlay it. You needed to do a lot of conversion to get an older adventure to work with the game.

And then, a couple of years after the edition was released, a revised version came out. (3.5E). This made a slew of changes, and though it’s described as a “half” edition, I would describe it as an entirely new edition. However, since it kept the same mathematical underpinnings as 3E, you could use adventures and monster books from one with the other. Not so much with character options.

• Dungeons & Dragons 3E
• Dungeons & Dragons 3.5E (should have been called 4E)

There’s no doubt about it: D&D 3E was a complicated game. So many options, and it could be absolutely overwhelming for DMs to run. So, D&D got a completely reworked edition, and this was the biggest change yet. It also wasn’t successful by D&D standards. Dungeons & Dragons 4E was a good game, but not a great game – and D&D needs to be a great game. Lots of people left (some went to Paizo’s Pathfinder, which itself was a revision of D&D 3.5E – and yes, if published under the D&D name, would have counted as a new edition).

Now here’s the one oddity where I don’t think it got a new edition: D&D 4E Essentials. This was a revised version of the 4E books, presenting classes in a different manner and hopefully being streamlined. However, it didn’t change that much about the game. And my group were very happy to keep using our main 4E core books and supplements alongside the 4E Essentials books and using powers from both.

It’s slightly complicated by how 4E was the one “living” edition where rules changes were made all the time. So, although D&D Essentials rewrote the Magic Missile spell, we’d seen a lot of this stuff already happen. (One of the big problems with 4E was that most of the PHB was changed by errata and you’d be “wrong” using it as written. This is one reason that 5E hasn’t seen many changes in errata when something doesn’t work as intended).

• Dungeons & Dragons 4E

And then we get D&D 5E. It managed to last ten years, which is excellent for an edition of D&D. (Both AD&D and AD&D 2E lasted about that long). Great edition, but it’s got a few cracks.

So, Wizards of the Coast are going to “revise” it. And by revise, I mean rewrite every class, race, and monster in the game, and likely most of the spells. Part of this seems to involve changing the levels that subclasses plug into, which makes any old supplement that presented a subclass fail to work with the new system (and any new supplement with subclasses incompatible with the old).

To me, it seems very, very close to what happened between AD&D 1E and AD&D 2E. And not all that dissimilar to the B/X to BECM D&D changes.

Which under how I see these things, should mean that it is called “Dungeons & Dragons, 6^th edition”. (Although 6E is, as you can see if you count all the editions above, not perhaps the most accurate term).

But instead, according to Wizards’ marketing speak, it’ll just be 5E Revised. Probably.

Let’s call it what it is – a new edition of the game.

• Dungeons & Dragons 5E
• Dungeons & Dragons 6E (5E Revised, whatever)

These are the four main groupings of Dungeons & Dragons over the years. I can see arguments for splitting OD&D + Holmes Basic away from the AD&D / Basic lines, and splitting Advanced from Basic, but I think this is a good enough approximation.

Between editions in the same grouping, the most compatibility problems you had came with character options. AD&D 1E doesn’t have that many official character option supplements (almost none, I’d say – Unearthed Arcana is the only that comes to mind). But plugging the Complete Fighter into your AD&D game would raise a few issues. Taking Sword & Fist (a 3E) supplement and using it with an AD&D game? Nah, not a good idea.

Monsters? Those transferred pretty easily between AD&D 1E and 2E and the Basic D&D line. I expect it’ll be the same between D&D 5E and D&D 6E. Adventures likewise, since they were mostly requiring monster rules – although a few checks involving non-weapon proficiencies might cause issues.

So, I’m working on this definition:

If you need to buy a new set of D&D core books to use (all) future content, then it’s a new edition.