Mechanically Distinct Editions of D&D

[tdenmark]

If editions mean mechanically distinct core rules, how many does D&D have?

10 editions: OD&D, Holmes, AD&D, B/X, BECMI, 2e, 3e, 3.5, 4e, & 5e.

Agree? Disagree? Are there more, or less?

[ThrorII]

I would argue that OD&D, Holmes, B/X, and BECMI are 'variations' rather than editions. Much of the core rules are the same. You could take a 1976 player of OD&D+Greyhawk and drop them in to a 1998 BECMI game and they would have no problem keeping up, and would only consider the differences as 'house rules'.

I would argue that AD&D 1e an 2e are a 'second edition', and that 3e/3.5e, 4e, and 5e are each different editions.

[atlantean]

I'm one of the mean spirited grognards that have never accepted WOTC D&D as the same game as that was put out by TSR. SO using Thomden's list, there have been five editions of one game and five editions of that other game.

[tdenmark]

Apr 21, 2023 14:12:36 GMT -6 ThrorII said:

I would argue that OD&D, Holmes, B/X, and BECMI are 'variations' rather than editions. Much of the core rules are the same. You could take a 1976 player of OD&D+Greyhawk and drop them in to a 1998 BECMI game and they would have no problem keeping up, and would only consider the differences as 'house rules'.

I would argue that AD&D 1e an 2e are a 'second edition', and that 3e/3.5e, 4e, and 5e are each different editions.

We combined D&D and AD&D material and didn't even think of them as different games. I distinctly recall playing Keep on the Borderlands and Isle of Dread and using the hardbound AD&D books, in middle school.

It wasn't until much later I encountered players who considered a single digit difference in some random table or ability a virtually incompatible difference. A difference is a difference is a difference.

But then nowadays I play so loose that I use all my old D&D books in our 5e campaign and do any needed conversions on the fly.

Side note, my daughter is having her friends over to play D&D...without me! So weird, she's one of the sporty types and her friends are all the "cool" athletic types, and they're into D&D. Different times!

[tdenmark]

Apr 21, 2023 14:13:45 GMT -6 atlantean said:

I'm one of the mean spirited grognards that have never accepted WOTC D&D as the same game as that was put out by TSR. SO using Thomden's list, there have been five editions of one game and five editions of that other game.

I don't go quite that far. There are changes I really disagree with, but from the WotC era there are a handful of mechanics I use in my old-school game:

• Ascending AC
• Conditions
• Damage Types (which is really just an evolution of the Attack/Damage types listed in B/X)
• Advantage/Disadvantage (which is really a mechanic from a Fiend Folio monster)

And the 5e Monster Manual is a great book. Most of the 5e DMG is just tools to help with running the game that really, you could use it with virtually any RPG.

But I can't stand what they did with Saving Throws. And combat got WAY too complicated. They dialled that back in 5e, but it's still too much.

I will agree with you though, there is a hard demarcation between 2e and 3e. And 3e, 4e, and 5e are very different games from one another. So you could ultra simplify the editions to:

D&D (OD&D - 2e) and the WotC D&D's 3.0, 3.5, 4, 5

By this counting 5th edition really is 5th edition!

[cadriel]

I'd say two.

OD&D, Holmes, AD&D 1e, B/X, BECMI, and AD&D 2e share the same basic mechanical core. Combat is roll high on an armor class-based calculation that gets easier as you level up, saving throws are rolled against static targets that get lower as you level up, you roll a d6 for surprise, secret doors, wandering monsters, etc. Obviously there are changes; AD&D PCs are a bit more robust and you have to take that into account when moving material between editions. But the same basic structure is there between games.

WotC D&D 3e, 4e, and 5e are basically similar. All of them are built around a core mechanic of d20+stat+skill/save/to hit bonus vs DC, all of which get higher as you level up. 4e and 5e both took the 3e core and put it in a very different character building paradigm but the core activity is the same. All of them have target numbers that stay relatively same-ish as you go up in level. You could separate them because of significant differences - 3e and 4e are more built on a treadmill of steadily increasing bonuses while 5e tries to restrain this with bounded accuracy, while each handles saves differently, but I feel like these are cars built with the same engine, trying to do different things with it each time.

If you wanted to be more differentiated you could argue for OD&D/Holmes/BX/BECMI as "Classic", 1e and 2e as "AD&D", 3e and 3.5e as "3e", 4e as "4e" and 5e as "5e" for 5 total editions. But I tend to think they're 2 with a few subcategories in each.

[skars]

I think the combat order of operations is what really sets each "edition" or grouping of editions apart along with how surprise, initiative, and when/how missile/magic occur.

[tdenmark]

Apr 21, 2023 18:38:07 GMT -6 cadriel said:

I'd say two.

OD&D, Holmes, AD&D 1e, B/X, BECMI, and AD&D 2e share the same basic mechanical core. Combat is roll high on an armor class-based calculation that gets easier as you level up, saving throws are rolled against static targets that get lower as you level up, you roll a d6 for surprise, secret doors, wandering monsters, etc. Obviously there are changes; AD&D PCs are a bit more robust and you have to take that into account when moving material between editions. But the same basic structure is there between games.

WotC D&D 3e, 4e, and 5e are basically similar. All of them are built around a core mechanic of d20+stat+skill/save/to hit bonus vs DC, all of which get higher as you level up. 4e and 5e both took the 3e core and put it in a very different character building paradigm but the core activity is the same. All of them have target numbers that stay relatively same-ish as you go up in level. You could separate them because of significant differences - 3e and 4e are more built on a treadmill of steadily increasing bonuses while 5e tries to restrain this with bounded accuracy, while each handles saves differently, but I feel like these are cars built with the same engine, trying to do different things with it each time.

If you wanted to be more differentiated you could argue for OD&D/Holmes/BX/BECMI as "Classic", 1e and 2e as "AD&D", 3e and 3.5e as "3e", 4e as "4e" and 5e as "5e" for 5 total editions. But I tend to think they're 2 with a few subcategories in each.

I kind of like that. Only 2 editions of D&D have ever been made. With only minor variations within those editions.

But really, don't you think you could run the The Hidden Shrine of Tamoachan with 5e and do any conversions on the fly with only little effort?

[tdenmark]

Apr 21, 2023 22:57:03 GMT -6 skars said:

I think the combat order of operations is what really sets each "edition" or grouping of editions apart along with how surprise, initiative, and when/how missile/magic occur.

That does seem to be the thing that gets fiddled with the most. I don't think a perfect order exists, it is all so circumstantial, requires the DM to moderate each situation.

[Desparil]

Apr 21, 2023 23:19:18 GMT -6 tdenmark said:

I kind of like that. Only 2 editions of D&D have ever been made. With only minor variations within those editions.

But really, don't you think you could run the The Hidden Shrine of Tamoachan with 5e and do any conversions on the fly with only little effort?

I've run B2 and X2 pretty close to this way. I did a few conversions ahead of time for monsters that aren't in the 5E corpus (or at least weren't at the time, I haven't kept up with all of what was in the Volo's or Mordenkainen's books) like the giant amoeba or aranea. Even for those, though, mostly I just calculated average hit points and doubled that number, changed AC to ascending, assigned a to-hit bonus, and assigned some modifiers to beef up damage rolls (so 1d6 becomes 1d6+3 or whatever), and that was it.

[cadriel]

Apr 21, 2023 23:19:18 GMT -6 tdenmark said:

Apr 21, 2023 18:38:07 GMT -6 cadriel said:

I'd say two.

OD&D, Holmes, AD&D 1e, B/X, BECMI, and AD&D 2e share the same basic mechanical core. Combat is roll high on an armor class-based calculation that gets easier as you level up, saving throws are rolled against static targets that get lower as you level up, you roll a d6 for surprise, secret doors, wandering monsters, etc. Obviously there are changes; AD&D PCs are a bit more robust and you have to take that into account when moving material between editions. But the same basic structure is there between games.

WotC D&D 3e, 4e, and 5e are basically similar. All of them are built around a core mechanic of d20+stat+skill/save/to hit bonus vs DC, all of which get higher as you level up. 4e and 5e both took the 3e core and put it in a very different character building paradigm but the core activity is the same. All of them have target numbers that stay relatively same-ish as you go up in level. You could separate them because of significant differences - 3e and 4e are more built on a treadmill of steadily increasing bonuses while 5e tries to restrain this with bounded accuracy, while each handles saves differently, but I feel like these are cars built with the same engine, trying to do different things with it each time.

If you wanted to be more differentiated you could argue for OD&D/Holmes/BX/BECMI as "Classic", 1e and 2e as "AD&D", 3e and 3.5e as "3e", 4e as "4e" and 5e as "5e" for 5 total editions. But I tend to think they're 2 with a few subcategories in each.

I kind of like that. Only 2 editions of D&D have ever been made. With only minor variations within those editions.

But really, don't you think you could run the The Hidden Shrine of Tamoachan with 5e and do any conversions on the fly with only little effort?

I do think 5e (more than 3e or 4e) is able to run earlier edition modules without much effort, partly by design; after all, the material that was used to balance 5e during its public playtest included B2 Keep on the Borderlands. But you could take B2 and run it with the same statistics in 2e AD&D or OD&D without a hitch, whereas for 5e you do need to convert all of the monsters. (I also wonder how well you could do Curse of Strahd with AD&D 2e.)

That's why I think of the functional difference as the switch from multiple mechanics to a single d20 mechanic. In a very loose sense the d20 mechanic was present in OD&D, in that Dexterity gave you a bonus for ranged attacks, so you had a stat-based bonus to a d20 roll versus a target number (based on class, level, and AC of the target). But I think the core idea that "everything is resolved with a d20 roll" is a different core engine to the way that pre-2000 D&D did things.

To me, saving throws are possibly the most important change. They went from a system of absolute improvement (your saves get easier as you level up) to one of relative improvement (your save bonus goes up but it's usually against a higher difficulty). This makes spellcasters simply better in 3e and 5e, since realistically you need a similar number to save versus a spell at first and tenth levels, whereas in the older D&D the tenth level character simply has an easier time with rolling saves.

[jeffb]

For myself- there is basically TSR D&D. Those editions are all similar enough. Details change, but it all runs the same at the table for the most part.

The WOTC editions are all their own thing individually. I happen to like this major variance from edition to edition and I love the fact that 3E and 4E and 5E are drastically different. I may not like a certain edition, but I'm all for bringing something fresh and new to the table for each edition, instead of re-runs (which is pretty much TSR D&D through the years).

[capitalbill]

Maybe 11?

I tend to view the later 2nd Edition Skills and Powers era stuff as kind of a blurry transitionary half step towards 3rd Edition. Call it 2.75e.

Personally, I also see a bigger dividing line parked kind of in the early/middle of 2e. Then with smaller closer-related product groupings of: OD&D, Holmes, much of AD&D; B/X, BECMI; later AD&D, early 2e; and then the rest (I don't try divide this half of the editions as I have much less interest and experience in it).

[dicebro]

I view OD&D without supplements as its own edition when it comes to the mechanics.

[waysoftheearth]

Surely a mechanically unique part of OD&D (c.1974) is the distinction between normal and fantastic combat and its dependence on/reference to other CM-isms?

Also, OD&D offers interchangeable combat “systems” (which really means: "attack matrices"). The default combat system is 2d6-based, and the 3LBB text is arguably written around this assumption. Later editions, from Holmes, switched to the Alternative, d20-based, attack matrices and thereafter defined combat exclusively in these terms.

[Finarvyn]

I haven't put a lot of thought into this, but my gut says 3 editions. My "mechanically similar" test is simply the ease that I have been able to take a product off the shelf and run it in whatever rules set I happen to be using for my group at the time.

I can pick up any module for OD&D, AD&D/2E, B/X and most of the clones and run it with pretty much any of the other rules. I did this when I play-tested C&C using AD&D modules, having a stack of monster manuals from various editions and grabbing whatever monsters I want, and running those adventures without much adjustment at all. I can even run most of those modules using 5E rules. All of those editions seem mechanically similar to me because of this. (I don't count ascending vs descending AC as a real mechanical difference, as I can "fix" it with one simple chart or equation. 5E's hit points are skewed from the others, but it's a simple "multiply by two" or "divide by two" sort of solution. DCC's levels have a similar issue, but it's a quick fix and not a major conversion.) I should mention that I tend to run low-level games, so at high levels it's possible that all of those games/editions would diverge quite a bit.

3E seemed very different to me at the time, and it still seems very different to me now. For whatever reason, converting from 3E to virtually any other game system seems like a real chore. The attribute scale is off, the power level seems off. Monster information is pages instead of a paragraph, which is a big annoyance for me. The mechanics seem intertwined enough where a person can't just ignore stuff without a significant impact on gameplay.

4E is a totally different thing to me and seems nothing like D&D. If it had been marketed with a different name I doubt that I would have thought, "hey, they stole D&D here."

When 5E first came out I thought the same thing as 3E, but through play I have found that even though the balance is different from OD&D/AD&D/etc, I can "wing it" and run DCC modules, AD&D modules, and so on, without much problem. Ironically, I find that running 5E modules with 5E is more of a challenge. So, I could buy a "5E is its own edition" discussion, but for me I can run 5E with old school modules so it's not so different after all.

Your mileage may vary.

[Punkrabbitt]

0E through the end of TSR is all mechanically similar enough to me for them to be lumped together. 3/3.5E makes a distinct break. 4E goes in a thrid direction entirely. 5E is vaguely compatible with the TSR-era stuff. When I am browsing the free stuff online, I don't even bother with 3E/3.5E/Pathfinder or 4E stuff, as it seems entirely unusable with WB:FMAG. I was doing 5E stuff for a while, but then I got mad at D&D for the OGL problem earlier this year and I shun 5E products as well. Hopefully I will get over that one soon...

[tdenmark]

Apr 22, 2023 21:23:07 GMT -6 Punkrabbitt said:

0E through the end of TSR is all mechanically similar enough to me for them to be lumped together. 3/3.5E makes a distinct break. 4E goes in a thrid direction entirely. 5E is vaguely compatible with the TSR-era stuff. When I am browsing the free stuff online, I don't even bother with 3E/3.5E/Pathfinder or 4E stuff, as it seems entirely unusable with WB:FMAG. I was doing 5E stuff for a while, but then I got mad at D&D for the OGL problem earlier this year and I shun 5E products as well. Hopefully I will get over that one soon...

3.5 was different enough, and I was invested in 3.0 enough that I didn't have the bandwidth or interest in learning 3.5. From there I kind of faded out. A play session of 4.0 at Gen Con the year it was released really turned me off, it was the most unnecessarily detailed miniatures skirmish game I'd ever played, and decidedly NOT D&D. Several comments here lump all WotC era D&D together, but I find 5e closer to B/X & BECMI D&D than even 2e is, in many ways.

So, this is fun to try and categorize them, but ultimately I'm not sure it is possible to really clearly and definitively identify just how many editions of D&D there has been.

[Finarvyn]

Apr 22, 2023 23:29:05 GMT -6 tdenmark said:

So, this is fun to try and categorize them, but ultimately I'm not sure it is possible to really clearly and definitively identify just how many editions of D&D there has been.

Agreed, which is why there are so many sub-boards at places like this one and Dragonsfoot. Seeing the forest instead of the trees makes the trees all look pretty much alike, but when you look at the individual trees they clearly aren't the same. I guess we would have to spend a lot of time defining "mechanically" since some have pointed out that 2d6 isn't 1d20 and so on.

[thegreyelf]

Apr 21, 2023 18:38:07 GMT -6 cadriel said:

I'd say two.

OD&D, Holmes, AD&D 1e, B/X, BECMI, and AD&D 2e share the same basic mechanical core. Combat is roll high on an armor class-based calculation that gets easier as you level up, saving throws are rolled against static targets that get lower as you level up, you roll a d6 for surprise, secret doors, wandering monsters, etc. Obviously there are changes; AD&D PCs are a bit more robust and you have to take that into account when moving material between editions. But the same basic structure is there between games.

I agree with this 100%. B/X and BECMI are simplifications of OD&D built off of the 3LBBs, while Holmes and AD&D are OD&D plus all the supplements. ALL of these games form the same game mechanically speaking, as evidenced by the fact that you can run ANY B/X, BECMI, or AD&D adventure module with ANY of those versions of the game, and zero adaptation is required from a rules standpoint. I know...because I've done it. Many times.

WotC D&D 3e, 4e, and 5e are basically similar. All of them are built around a core mechanic of d20+stat+skill/save/to hit bonus vs DC, all of which get higher as you level up. 4e and 5e both took the 3e core and put it in a very different character building paradigm but the core activity is the same. All of them have target numbers that stay relatively same-ish as you go up in level. You could separate them because of significant differences - 3e and 4e are more built on a treadmill of steadily increasing bonuses while 5e tries to restrain this with bounded accuracy, while each handles saves differently, but I feel like these are cars built with the same engine, trying to do different things with it each time.

I don't QUITE agree with this. 3.x, 4e, and 5e, while they started from the same core idea of d20 roll high vs. DC, are so distinct from one another that you cannot easily use one to the other without pretty extensive conversion work necessary. The work to be done is easy enough to do, but robust enough that doing it on the fly is going to be sloppy, and you can't, for example, use a 3.x monster stat block with a 4e or 5e adventure module. Each of these three is a distinct adventure.

If you wanted to be more differentiated you could argue for OD&D/Holmes/BX/BECMI as "Classic", 1e and 2e as "AD&D", 3e and 3.5e as "3e", 4e as "4e" and 5e as "5e" for 5 total editions. But I tend to think they're 2 with a few subcategories in each.

I would cite four editions: OD&D, B/X, Holmes, AD&D 1e, BECMI, AD&D 2e as the first, followed by 3.x as the second, 4e as the third, and 5e as the fourth.

[talysman]

I think the issue here is that defining "editions" in terms of being "mechanically distinct" is kind of meaningless when not every distinction affects the game the same way.

I think I see three or four kinds of "mechanical distinction".

• GM-Side. Stuff players never need to see, such as dungeon stocking rules.
• Superficial Differences. Changes to numbers, dice ranges or other details that don't change the process or the focus of play.
• Functional Differences.Changes to components such as classes, spells, or monsters that significantly alter play.
• Structural Differences.Changes to the process or context of play itself that shifts the feel or focus of the entire game.

We can basically ignore GM-side stuff if we want to, which is why I said there are "three or four kinds".

The switch from 1d6 for all weapon damage to variable weapon damage, or from descending AC to ascending AC, is noticeable, but basically superficial, because we could change it back. Gameplay would still be mostly the same. In contrast, a functional change like limiting spells known can alter the way M-Us are used and definitely changes gameplay. The line between superficial and functional differences will still be debatable, though.

The big differences are the structural ones, in my opinion. Changing combat from general actions like attack, retreat or flee to individual maneuvers shifts the focus from exploration and planning to individual combat tactics.

I'd argue that one structural difference = a mechanically distinct edition, but functional differences only make the edition mechanically distinct if there are enough of them, and superficial differences never make an edition mechanically distinct, no matter how many there are. I haven't decided yet how many functional differences are "enough" yet, other than "more than just one". And I'm not sure what the best way is to talk about edition mixing and homebrews.

[waysoftheearth]

The change from OD&D's 6 monster level tables and (steep) monster distribution table to AD&D's 10 monster level tables and (less steep) monster distribution table, and then to 3e's challenge rating system, is a substantive impact on the difficulty level (to players) of likely combat encounters... but, for the most part, is hidden behind the DM screen.

[robertsconley]

This is what I posted on rpg.stackexchange.com answering a similar question.

• Chainmail Fantasy Supplement in 1971
• Supplement I: Greyhawk published in 1975
• Basic Dungeons & Dragons by Holmes in 1977
• Advanced Dungeons & Dragons in 1977-1979
• Basic/Expert Dungeons & Dragons by Moldvay/Cook in 1981
• Basic/Expert/Companion/Master/Immortal Dungeons & Dragons by Mentzer in 1983
• Unearthed Arcana for AD&D (Some say that this made AD&D 1.5.)
• Advanced Dungeons & Dragons 2nd Edition in 1989
• Rules Cyclopedia for Dungeons & Dragons in 1991
• Skills & Powers for AD&D 2nd edition in 1995
• Dungeons & Dragons 3.0 in 2000
• Dungeons & Dragons 3.5 in 2003
• Dungeons & Dragons 4.0 in 2008
• D&D Next - Intermediate development version
• Dungeons & Dragons 5.0 in 2014

[Parzival]

Spells can be significantly different among editions. Later editions tend to try to specifically limit and weaken well-known spells, which affects a players expectations and tactics considerably. And of course there are changes in how spellcasting works entirely. Both of these will mess up your expectations for adventures which involve spellcasters. (And don’t get me started on spell “nerfing” in modern editions.)

[tdenmark]

Apr 23, 2023 17:35:47 GMT -6 robertsconley said:

This is what I posted on rpg.stackexchange.com answering a similar question.

• Chainmail Fantasy Supplement in 1971
• Supplement I: Greyhawk published in 1975
• Basic Dungeons & Dragons by Holmes in 1977
• Advanced Dungeons & Dragons in 1977-1979
• Basic/Expert Dungeons & Dragons by Moldvay/Cook in 1981
• Basic/Expert/Companion/Master/Immortal Dungeons & Dragons by Mentzer in 1983
• Unearthed Arcana for AD&D (Some say that this made AD&D 1.5.)
• Advanced Dungeons & Dragons 2nd Edition in 1989
• Rules Cyclopedia for Dungeons & Dragons in 1991
• Skills & Powers for AD&D 2nd edition in 1995
• Dungeons & Dragons 3.0 in 2000
• Dungeons & Dragons 3.5 in 2003
• Dungeons & Dragons 4.0 in 2008
• D&D Next - Intermediate development version
• Dungeons & Dragons 5.0 in 2014

Love it! A difference is a difference!

[Mordorandor]

Apr 23, 2023 17:35:47 GMT -6 robertsconley said:

This is what I posted on rpg.stackexchange.com answering a similar question.

• Chainmail Fantasy Supplement in 1971
• Supplement I: Greyhawk published in 1975
• Basic Dungeons & Dragons by Holmes in 1977
• Advanced Dungeons & Dragons in 1977-1979
• Basic/Expert Dungeons & Dragons by Moldvay/Cook in 1981
• Basic/Expert/Companion/Master/Immortal Dungeons & Dragons by Mentzer in 1983
• Unearthed Arcana for AD&D (Some say that this made AD&D 1.5.)
• Advanced Dungeons & Dragons 2nd Edition in 1989
• Rules Cyclopedia for Dungeons & Dragons in 1991
• Skills & Powers for AD&D 2nd edition in 1995
• Dungeons & Dragons 3.0 in 2000
• Dungeons & Dragons 3.5 in 2003
• Dungeons & Dragons 4.0 in 2008
• D&D Next - Intermediate development version
• Dungeons & Dragons 5.0 in 2014

I'd say 5 editions. 

Edition 1

• Original D&D 1974
  
• Supplement I: Greyhawk published in 1975
• Basic Dungeons & Dragons by Holmes in 1977
• Basic/Expert Dungeons & Dragons by Moldvay/Cook in 1981
• Basic/Expert/Companion/Master/Immortal Dungeons & Dragons by Mentzer in 1983
• Rules Cyclopedia for Dungeons & Dragons in 1991
  

Edition 2

• Advanced Dungeons & Dragons in 1977-1979
• Unearthed Arcana for AD&D (Some say that this made AD&D 1.5.)
• Advanced Dungeons & Dragons 2nd Edition in 1989
• Skills & Powers for AD&D 2nd edition in 1995
  

Edition 3

• Dungeons & Dragons 3.0 in 2000
• Dungeons & Dragons 3.5 in 2003

Edition 4

• Dungeons & Dragons 4.0 in 2008

Edition 5

• Dungeons & Dragons 5.0 in 2014

An edition being something that which would make it impossible (or "sufficiently difficult" (ambiguous for a reason)) to back-port adventures, characters, monsters, etc. They are basically 5 different games.

[Parzival]

Apr 24, 2023 11:32:34 GMT -6 Mordorandor said:

Apr 23, 2023 17:35:47 GMT -6 robertsconley said:

This is what I posted on rpg.stackexchange.com answering a similar question.

• Chainmail Fantasy Supplement in 1971
• Supplement I: Greyhawk published in 1975
• Basic Dungeons & Dragons by Holmes in 1977
• Advanced Dungeons & Dragons in 1977-1979
• Basic/Expert Dungeons & Dragons by Moldvay/Cook in 1981
• Basic/Expert/Companion/Master/Immortal Dungeons & Dragons by Mentzer in 1983
• Unearthed Arcana for AD&D (Some say that this made AD&D 1.5.)
• Advanced Dungeons & Dragons 2nd Edition in 1989
• Rules Cyclopedia for Dungeons & Dragons in 1991
• Skills & Powers for AD&D 2nd edition in 1995
• Dungeons & Dragons 3.0 in 2000
• Dungeons & Dragons 3.5 in 2003
• Dungeons & Dragons 4.0 in 2008
• D&D Next - Intermediate development version
• Dungeons & Dragons 5.0 in 2014

I'd say 5 editions. 

Edition 1

• Original D&D 1974
  
• Supplement I: Greyhawk published in 1975
• Basic Dungeons & Dragons by Holmes in 1977
• Basic/Expert Dungeons & Dragons by Moldvay/Cook in 1981
• Basic/Expert/Companion/Master/Immortal Dungeons & Dragons by Mentzer in 1983
• Rules Cyclopedia for Dungeons & Dragons in 1991
  

Edition 2

• Advanced Dungeons & Dragons in 1977-1979
• Unearthed Arcana for AD&D (Some say that this made AD&D 1.5.)
• Advanced Dungeons & Dragons 2nd Edition in 1989
• Skills & Powers for AD&D 2nd edition in 1995
  

Edition 3

• Dungeons & Dragons 3.0 in 2000
• Dungeons & Dragons 3.5 in 2003

Edition 4

• Dungeons & Dragons 4.0 in 2008

Edition 5

• Dungeons & Dragons 5.0 in 2014

An edition being something that which would make it impossible (or "sufficiently difficult" (ambiguous for a reason)) to back-port adventures, characters, monsters, etc. They are basically 5 different games.

I agree with this standard, but would therefore combine your Editions 1 and Edition 2 into a single edition. The differences between AD&D, Classic D&D, and OD&D are minimal enough to me that I can easily run a party from any set in an adventure originally published for any other set. Yes, the details of how things are played can become very specific and distinct, but in terms of an adventure that all falls away. The monsters change only marginally, the treasures are the same, the traps will work no matter what system, and even the magic items can easily fit in place. (And the PCs all die in the same horrible ways… ;-) )

[talysman]

Apr 23, 2023 16:38:30 GMT -6 waysoftheearth said:

The change from OD&D's 6 monster level tables and (steep) monster distribution table to AD&D's 10 monster level tables and (less steep) monster distribution table, and then to 3e's challenge rating system, is a substantive impact on the difficulty level (to players) of likely combat encounters... but, for the most part, is hidden behind the DM screen.

The use of monster or challenge levels makes a good example of how GM-Side differences, Functional differences, and Structural differences can exist at the same time and interact in unexpected ways.

Monster level by itself is functional. Even if it is effectively hidden behind the GM screen, we know it affects gameplay if the max monster level available in Greyhawk or AD&D is higher than the max level available in OD&D without Greyhawk.

The monster level tables, however, are GM-side. The rules explicitly state that monsters can be specifically placed instead of randomly placed, and even if the tables are used, GMs are told to change the tables depending on the dungeon context. And that's assuming the GM decides to use the tables (and use them correctly,) or takes them as a suggestion to ignore. All players know is that some GMs have tougher dungeons in general than others, but there's no way to know why some GMs are tougher unless they spill the beans.

The switch from monster level to challenge level, however, happened alongside a structural change to how monsters are placed. In OD&D and AD&D, the assumption is that monster level is usually linked to dungeon level, and it's possible for players to wander into areas they can't handle with combat. In WotC D&D, the assumption is that challenge level is linked to character level, and encounters should be balanced for party.

Apr 24, 2023 11:32:34 GMT -6 Mordorandor said:

Apr 23, 2023 17:35:47 GMT -6 robertsconley said:

This is what I posted on rpg.stackexchange.com answering a similar question.

• Chainmail Fantasy Supplement in 1971
• Supplement I: Greyhawk published in 1975
• Basic Dungeons & Dragons by Holmes in 1977
• Advanced Dungeons & Dragons in 1977-1979
• Basic/Expert Dungeons & Dragons by Moldvay/Cook in 1981
• Basic/Expert/Companion/Master/Immortal Dungeons & Dragons by Mentzer in 1983
• Unearthed Arcana for AD&D (Some say that this made AD&D 1.5.)
• Advanced Dungeons & Dragons 2nd Edition in 1989
• Rules Cyclopedia for Dungeons & Dragons in 1991
• Skills & Powers for AD&D 2nd edition in 1995
• Dungeons & Dragons 3.0 in 2000
• Dungeons & Dragons 3.5 in 2003
• Dungeons & Dragons 4.0 in 2008
• D&D Next - Intermediate development version
• Dungeons & Dragons 5.0 in 2014

I'd say 5 editions. 

Edition 1

• Original D&D 1974
  
• Supplement I: Greyhawk published in 1975
• Basic Dungeons & Dragons by Holmes in 1977
• Basic/Expert Dungeons & Dragons by Moldvay/Cook in 1981
• Basic/Expert/Companion/Master/Immortal Dungeons & Dragons by Mentzer in 1983
• Rules Cyclopedia for Dungeons & Dragons in 1991
  

Edition 2

• Advanced Dungeons & Dragons in 1977-1979
• Unearthed Arcana for AD&D (Some say that this made AD&D 1.5.)
• Advanced Dungeons & Dragons 2nd Edition in 1989
• Skills & Powers for AD&D 2nd edition in 1995
  

Edition 3

• Dungeons & Dragons 3.0 in 2000
• Dungeons & Dragons 3.5 in 2003

Edition 4

• Dungeons & Dragons 4.0 in 2008

Edition 5

• Dungeons & Dragons 5.0 in 2014

An edition being something that which would make it impossible (or "sufficiently difficult" (ambiguous for a reason)) to back-port adventures, characters, monsters, etc. They are basically 5 different games.

My own tentative mechanically distinct editions list, with a focus on structural differences:

1. OD&D (the starting point)
2. B/X (distinct because of spells known)
3. AD&D (distinct because of proficiencies and others)
4. AD&D 2e (maybe distinct because of clerical healing changes?)
5. WotC D&D 3e (several structural changes)
6. WotC D&D 4e (generally recognized as extremely different)
7. WotC D&D 5e (3e with a few more changes and rollbacks)

I don't know enough about the kits and splatbooks from the 2e era to judge if they are structurally distinct from 2e itself. I'm guessing maybe yes, but I'm giving the late 1e changes via OA, WSG, and DSG a pass because non-weapon proficiencies seem like an evolution of the proficiencies idea.

[tdenmark]

Apr 24, 2023 11:32:34 GMT -6 Mordorandor said:

Apr 23, 2023 17:35:47 GMT -6 robertsconley said:

This is what I posted on rpg.stackexchange.com answering a similar question.

• Chainmail Fantasy Supplement in 1971
• Supplement I: Greyhawk published in 1975
• Basic Dungeons & Dragons by Holmes in 1977
• Advanced Dungeons & Dragons in 1977-1979
• Basic/Expert Dungeons & Dragons by Moldvay/Cook in 1981
• Basic/Expert/Companion/Master/Immortal Dungeons & Dragons by Mentzer in 1983
• Unearthed Arcana for AD&D (Some say that this made AD&D 1.5.)
• Advanced Dungeons & Dragons 2nd Edition in 1989
• Rules Cyclopedia for Dungeons & Dragons in 1991
• Skills & Powers for AD&D 2nd edition in 1995
• Dungeons & Dragons 3.0 in 2000
• Dungeons & Dragons 3.5 in 2003
• Dungeons & Dragons 4.0 in 2008
• D&D Next - Intermediate development version
• Dungeons & Dragons 5.0 in 2014

I'd say 5 editions. 

Edition 1

• Original D&D 1974
  
• Supplement I: Greyhawk published in 1975
• Basic Dungeons & Dragons by Holmes in 1977
• Basic/Expert Dungeons & Dragons by Moldvay/Cook in 1981
• Basic/Expert/Companion/Master/Immortal Dungeons & Dragons by Mentzer in 1983
• Rules Cyclopedia for Dungeons & Dragons in 1991
  

Edition 2

• Advanced Dungeons & Dragons in 1977-1979
• Unearthed Arcana for AD&D (Some say that this made AD&D 1.5.)
• Advanced Dungeons & Dragons 2nd Edition in 1989
• Skills & Powers for AD&D 2nd edition in 1995
  

Edition 3

• Dungeons & Dragons 3.0 in 2000
• Dungeons & Dragons 3.5 in 2003

Edition 4

• Dungeons & Dragons 4.0 in 2008

Edition 5

• Dungeons & Dragons 5.0 in 2014

An edition being something that which would make it impossible (or "sufficiently difficult" (ambiguous for a reason)) to back-port adventures, characters, monsters, etc. They are basically 5 different games.

This is how I see it too.

LBB to Greyhawk is a bigger jump than AD&D to AD&D 2e. So lumping the AD&D's together makes sense.

[Desparil]

Apr 24, 2023 13:09:17 GMT -6 tdenmark said:

This is how I see it too.

LBB to Greyhawk is a bigger jump than AD&D to AD&D 2e. So lumping the AD&D's together makes sense.

In many ways, the difference between OD&D with and without the supplements is analogous to the difference between playing AD&D 2E with and without the Player's Option books