This is a not a question about what is the OSR

I'm not terribly interested in questions of that sort as they are by nature pedantic affairs that never yield practical answers.

No I'm much more interested in the what set of mechanics do or do not make a game compatible with the OSR. Mainly what makes a game compatible with the monsters and adventures of the OSR world.

I've recently picked up the Fantasy Trip, it has the sole element of GURPS I really like, which is how elegant I think the 3d6 roll under mechanic is, I wonder if you could make a classless, leveless, 3d6 fantasy game and it generally work with the OSR adventures, monsters and modules as easy as a retroclone.

Quote from: Socratic-DM on December 10, 2023, 01:35:25 PM
This is a not a question about what is the OSR

I'm not terribly interested in questions of that sort as they are by nature pedantic affairs that never yield practical answers.

No I'm much more interested in the what set of mechanics do or do not make a game compatible with the OSR. Mainly what makes a game compatible with the monsters and adventures of the OSR world.

I've recently picked up the Fantasy Trip, it has the sole element of GURPS I really like, which is how elegant I think the 3d6 roll under mechanic is, I wonder if you could make a classless, leveless, 3d6 fantasy game and it generally work with the OSR adventures, monsters and modules as easy as a retroclone.

Well, TFT is certainly classified as old school these days. You could use D&D based old school adventures with it but it would take a bit of work to convert. All OSR mainstream fantasy material shares a lingua franca that is easily useable with OD&D, B/X, BECMI, and AD&D. Six statistics, class based, AC as static defense, and scaling HP are the core of it. TFT is available again so I don't why anyone would want a clone unless it offered something added that was really new and cool. Adventures written for TFT would be a better bet. Then again, with SJG's attitude you probably would have to make your own retro-clone in order to do that.

It depends on who you ask. Some people say to be OSR had better be a reworking of B/X, AD&D, and so on. Others will tell you it's any old game dating back to around 1983. Me? I think it's a reworking of any old game. Pundit IIRC will tell you it's got to be D&D based. If we could run a poll here it might give you a better view. I think I've seen polls here, but I can't fully recall.

If I read the OP correctly, the question could possibly be rephrased as "what games that aren't based on Basic D&D are easy to use OSR materials with?" If so, then I would say it comes down to how many shared assumptions there are between the two games.

Last year, I ran a campaign of Dragon Warriors (https://preview.drivethrurpg.com/en/product/90926/dragon-warriors) which I found to be pretty easy to use OSR material with. It's a different underlying system, but it's still a medieval fantasy game with a 3-18 attribute range and broadly comparable class and level progression. So if a module says an NPC is a 4th level fighter, I can go into the DW Companion book and just look up the average stats for a 4th rank knight or barbarian. Dragon Warriors doesn't have saving throws, but between attribute checks and the Evasion and Magic Defense stats, it's pretty easy to replace a saving throw if a module calls for one. It also doesn't have hit dice, but again, it's pretty easy to just say "well, this creature should probably have the same HP as a troll" or whatever, and then just find and replace.   

Quote from: Socratic-DM on December 10, 2023, 01:35:25 PM
This is a not a question about what is the OSR

I'm not terribly interested in questions of that sort as they are by nature pedantic affairs that never yield practical answers.

No I'm much more interested in the what set of mechanics do or do not make a game compatible with the OSR. Mainly what makes a game compatible with the monsters and adventures of the OSR world.

I've recently picked up the Fantasy Trip, it has the sole element of GURPS I really like, which is how elegant I think the 3d6 roll under mechanic is, I wonder if you could make a classless, leveless, 3d6 fantasy game and it generally work with the OSR adventures, monsters and modules as easy as a retroclone.

How can anyone answer that question before answering what the OSR is?

I mean, if you include Cepheus, Faserip, Warhammer Fantasy, The Fantasy Trip AND Old School D&D (2e tops by most accounts), then there's no compatible mechanics because you have diluted the meaning to encompass ALL Old School games up to 1977-89.

Now, you can use the modules from any game with any other game if you're willing to do the conversion.

Quote from: GeekyBugle on December 10, 2023, 03:45:33 PM

Quote from: Socratic-DM on December 10, 2023, 01:35:25 PM
This is a not a question about what is the OSR

I'm not terribly interested in questions of that sort as they are by nature pedantic affairs that never yield practical answers.

No I'm much more interested in the what set of mechanics do or do not make a game compatible with the OSR. Mainly what makes a game compatible with the monsters and adventures of the OSR world.

I've recently picked up the Fantasy Trip, it has the sole element of GURPS I really like, which is how elegant I think the 3d6 roll under mechanic is, I wonder if you could make a classless, leveless, 3d6 fantasy game and it generally work with the OSR adventures, monsters and modules as easy as a retroclone.

How can anyone answer that question before answering what the OSR is?

I mean, if you include Cepheus, Faserip, Warhammer Fantasy, The Fantasy Trip AND Old School D&D (2e tops by most accounts), then there's no compatible mechanics because you have diluted the meaning to encompass ALL Old School games up to 1977-89.

Now, you can use the modules from any game with any other game if you're willing to do the conversion.

I then should have been clear, OD&D, B/X, BECMI, and AD&D and clones, as they are easily no doubt the majority of retroclones out there.

Quote from: ForgottenF on December 10, 2023, 03:44:49 PM
If I read the OP correctly, the question could possibly be rephrased as "what games that aren't based on Basic D&D are easy to use OSR materials with?" If so, then I would say it comes down to how many shared assumptions there are between the two games.

Last year, I ran a campaign of Dragon Warriors (https://preview.drivethrurpg.com/en/product/90926/dragon-warriors) which I found to be pretty easy to use OSR material with. It's a different underlying system, but it's still a medieval fantasy game with a 3-18 attribute range and broadly comparable class and level progression. So if a module says an NPC is a 4th level fighter, I can go into the DW Companion book and just look up the average stats for a 4th rank knight or barbarian. Dragon Warriors doesn't have saving throws, but between attribute checks and the Evasion and Magic Defense stats, it's pretty easy to replace a saving throw if a module calls for one. It also doesn't have hit dice, but again, it's pretty easy to just say "well, this creature should probably have the same HP as a troll" or whatever, and then just find and replace.   

You are correct that would have been a better title, more precisely what I'm getting at is, I'd like to design something that has some of the same core assumption, but with a generally different expression.  so if I had a classless, leveless system, then having a monster Save as fighter 5 doesn't make sense, or if I have a health tracks, then HD don't make much sense, but I still want to be compatible with those things.

I'm also taking into account RPGpundit's adviice, everything really should consider early D&D in it's design phase, and I'd like to make something that has very different mechanical expressions, but which can really easily or on the fly use OSR D&D content.

Quote from: Socratic-DM on December 10, 2023, 04:11:27 PM

Quote from: ForgottenF on December 10, 2023, 03:44:49 PM
If I read the OP correctly, the question could possibly be rephrased as "what games that aren't based on Basic D&D are easy to use OSR materials with?" If so, then I would say it comes down to how many shared assumptions there are between the two games.

Last year, I ran a campaign of Dragon Warriors (https://preview.drivethrurpg.com/en/product/90926/dragon-warriors) which I found to be pretty easy to use OSR material with. It's a different underlying system, but it's still a medieval fantasy game with a 3-18 attribute range and broadly comparable class and level progression. So if a module says an NPC is a 4th level fighter, I can go into the DW Companion book and just look up the average stats for a 4th rank knight or barbarian. Dragon Warriors doesn't have saving throws, but between attribute checks and the Evasion and Magic Defense stats, it's pretty easy to replace a saving throw if a module calls for one. It also doesn't have hit dice, but again, it's pretty easy to just say "well, this creature should probably have the same HP as a troll" or whatever, and then just find and replace.   

You are correct that would have been a better title, more precisely what I'm getting at is, I'd like to design something that has some of the same core assumption, but with a generally different expression.  so if I had a classless, leveless system, then having a monster Save as fighter 5 doesn't make sense, or if I have a health tracks, then HD don't make much sense, but I still want to be compatible with those things.

I'm also taking into account RPGpundit's adviice, everything really should consider early D&D in it's design phase, and I'd like to make something that has very different mechanical expressions, but which can really easily or on the fly use OSR D&D content.

Most OSR games are "Basic D&D but X", and "Basic D&D but classless" is the one permutation I want to see but haven't, so I wish you luck with it.

Class and level are about as fundamental to the assumptions of D&D as you can get, so stripping those out and remaining compatible with OSR games is probably going to be a tall order. And if you're going to strip out hit points, then the Armor Class system probably won't make sense anymore, either.

So what does that leave you with? Not much. I guess if you still build your game around procedural dungeon crawling, that would line up with the sensibilities expressed by OSR modules. You'd want ready analogs for things like reaction rolls, surprise, the whole "listen at door -> search for traps -> disarm traps" workflow, and some mechanic that does the same job as saving throws, maybe with an approximate analogue for the Fort/Ref/Will system, since that's pretty easy to convert the Basic 5-save system to on the fly. That way you'd be preserving the same basic game-flow, even if the stats don't transfer over.

The stats not transferring isn't that big a deal, I suppose. Plenty of games include (or have fan-made) conversion guides for porting D&D stat blocks into their system. Savage Worlds has some particularly good ones you could possibly use for inspiration.

As a general rule, I find it easier to convert material from a more complex game to a simpler one, but that might not be very helpful advice. You can't go much simpler than B/X D&D and still have a game left to play.

Quote from: ForgottenF on December 10, 2023, 04:48:31 PM

Quote from: Socratic-DM on December 10, 2023, 04:11:27 PM

Quote from: ForgottenF on December 10, 2023, 03:44:49 PM
If I read the OP correctly, the question could possibly be rephrased as "what games that aren't based on Basic D&D are easy to use OSR materials with?" If so, then I would say it comes down to how many shared assumptions there are between the two games.

Last year, I ran a campaign of Dragon Warriors (https://preview.drivethrurpg.com/en/product/90926/dragon-warriors) which I found to be pretty easy to use OSR material with. It's a different underlying system, but it's still a medieval fantasy game with a 3-18 attribute range and broadly comparable class and level progression. So if a module says an NPC is a 4th level fighter, I can go into the DW Companion book and just look up the average stats for a 4th rank knight or barbarian. Dragon Warriors doesn't have saving throws, but between attribute checks and the Evasion and Magic Defense stats, it's pretty easy to replace a saving throw if a module calls for one. It also doesn't have hit dice, but again, it's pretty easy to just say "well, this creature should probably have the same HP as a troll" or whatever, and then just find and replace.   

You are correct that would have been a better title, more precisely what I'm getting at is, I'd like to design something that has some of the same core assumption, but with a generally different expression.  so if I had a classless, leveless system, then having a monster Save as fighter 5 doesn't make sense, or if I have a health tracks, then HD don't make much sense, but I still want to be compatible with those things.

I'm also taking into account RPGpundit's adviice, everything really should consider early D&D in it's design phase, and I'd like to make something that has very different mechanical expressions, but which can really easily or on the fly use OSR D&D content.

Most OSR games are "Basic D&D but X", and "Basic D&D but classless" is the one permutation I want to see but haven't, so I wish you luck with it.

Class and level are about as fundamental to the assumptions of D&D as you can get, so stripping those out and remaining compatible with OSR games is probably going to be a tall order. And if you're going to strip out hit points, then the Armor Class system probably won't make sense anymore, either.

So what does that leave you with? Not much. I guess if you still build your game around procedural dungeon crawling, that would line up with the sensibilities expressed by OSR modules. You'd want ready analogs for things like reaction rolls, surprise, the whole "listen at door -> search for traps -> disarm traps" workflow, and some mechanic that does the same job as saving throws, maybe with an approximate analogue for the Fort/Ref/Will system, since that's pretty easy to convert the Basic 5-save system to on the fly. That way you'd be preserving the same basic game-flow, even if the stats don't transfer over.

The stats not transferring isn't that big a deal, I suppose. Plenty of games include (or have fan-made) conversion guides for porting D&D stat blocks into their system. Savage Worlds has some particularly good ones you could possibly use for inspiration.

As a general rule, I find it easier to convert material from a more complex game to a simpler one, but that might not be very helpful advice. You can't go much simpler than B/X D&D and still have a game left to play.

Well thinking on the subject, monster and player stats generally don't need to be reflective of one another, and the stat that pulls the most heavy lifting in my opinion is HD in the case of monsters, as at least the retroclones I've seen it is their to hit bonus, and HP. and generally if xp is rewarded for killing, it scales from HD as well.

One concept of the game the health track, which is size + Stamina/constitution.  HD in place of the stamina or vitality type stat makes sense to me.

Likewise damage and number of attacks is preserved across my idea pretty well, saving throws is a bit more of a puzzler. I think as a goal of design for this is that B/X style monster cards should work flawlessly in this system.

Quote from: Socratic-DM on December 10, 2023, 05:38:04 PM
One concept of the game the health track, which is size + Stamina/constitution.  HD in place of the stamina or vitality type stat makes sense to me.

I guess? I'm not really visualizing what you mean by the health track, so I can't say.

Quote from: Socratic-DM on December 10, 2023, 05:38:04 PM
Likewise damage and number of attacks is preserved across my idea pretty well, saving throws is a bit more of a puzzler. I think as a goal of design for this is that B/X style monster cards should work flawlessly in this system.

The logical question then is what are you using in lieu of saving throws? What is the mechanic for dodging a falling statue or resisting a mind control spell?

To be fair, and GeekyBugle has already addressed this, what the OSR is directly affects what rules make something compatible with the OSR. However, since you narrowed it down a bit by specifically saying, " OD&D, B/X, BECMI, and AD&D and clones" that should make it a lot clearer.

Something to keep in mind is that the rules of a game (usually) influence how the players play the game. So take something like XP for gold. The players know they can get much much more XP for stealing 1,000gp from 10 goblins than they will ever get from slaying those 10 goblins. Therefore, their actions (usually) will align with this. They may pursue options that don't involve combat. That's also why settings like Mystara work so well: the rules are reflected in the setting, with also reflects the players' playstyle: everyone is expected to adventure, adventurers are frequently trying to create domains, and the races all reflect their game rules.

In my estimation, I think what makes a game OSR compatible is whether or not it's trying to corral the players into the OSR playstyle. I'm sure my definition of that playstyle won't be agreed upon by everyone, and I'm not trying to start any flame wars here, but I'll take a crack. The OSR playstyle is that of dungeon-crawling and exploration, with the eventual aim of creating a player domain. This is all held together by a rules set that isn't rules light, but isn't so airtight that you can't change them without derailing the rules set. This isn't a perfect definition, but it's what I'm gonna work off for now.

So for an example: I'd say B2: Keep on the Borderlands and OSRIC are compatible with the OSR, but Red Hand of Doom and 4th Edition D&D are not. But if a game swapped Strength for Power, or used ascending AC over Thac0, that doesn't really make a game non-OSR.

Personally, I think the stat block for monsters/npcs.

Are there hit dice and hit points (the latter maxing out at 300-400 for gods and kaiju)?  Is there an Armor Class? Does it go from 10 (or 9) down to -10 or so or up to 30 or so? (BECMI did have a wider range, to be fair)

Damage is also useful, but comparing it to a weapon can help, although many monsters should do a lot more damage than a weapon.

So something like AC 3(17); HD 5; hp 30; Atk 1-10/1-10  is pretty much the bare minimum to be OSR compatible.

Something for 5e or 3e or something else might have those elements, but not in the same ranges as OSR

The other thing I think what makes games OSR compatible is if they keep the old games (at least how we played back in the day) emphasis on resource management.

Like how far into the dungeon do we go before turning back? The characters resources are slowly whittled away, hit points are lost, spells are cast, you start reaching carrying capacity. And how much do you keep in reserve in case you run into a monster on the way home?

The nature of the old style D&D rules was that those things are generally gradually worn away. Sure there are cases when you could get killed,  usually failing a saving throw or doing something stupid, but overall it was ablative.

I don't think that works if your game doesn't have constantly increasing hit points and spell slots that aren't easily replaced.

My question is a bit more practical.  I have a small number of OSR books.


I am looking at the vast number of products on the market labeled OSR.  How do I tell which ones will be compatible with what I already have without a lot of farting around? 

Quote from: Socratic-DM on December 10, 2023, 01:35:25 PM
This is a not a question about what is the OSR

It will inevitably become that though.  It's difficult to determine what is compatible with the OSR without knowing what the OSR is. 

Quote from: yosemitemike on December 10, 2023, 11:08:49 PM
My question is a bit more practical.  I have a small number of OSR books.


I am looking at the vast number of products on the market labeled OSR.  How do I tell which ones will be compatible with what I already have without a lot of farting around? 

Quote from: Socratic-DM on December 10, 2023, 01:35:25 PM
This is a not a question about what is the OSR

It will inevitably become that though.  It's difficult to determine what is compatible with the OSR without knowing what the OSR is.

Not a complete list but it might help you:

http://taxidermicowlbear.weebly.com/dd-retroclones.html