PBTA <3 OSR? Can the design philosophies be combined?

I would say that a PbtA GM Move and an OSR GM ruling for what happens to the PC who just missed a roll, are essentially the same thing. The difference between the two play styles comes earlier in the process of players doing stuff:

In PbtA game, the player states what their character is doing, the GM then decided if mechanics are required and if so calls for a Move, the player rolls and then if it is successful, follows the rules in the Move, if it fails the GM invents or chooses a GM Move.

In an OSR game the player states what their character is doing, the GM then decides if mechanics are required. If they are, there might be something suitable in the system already (to hit roll / a Halfling’s hide in wilderness chance / a Thief’s climb %) or the GM might need to make a ruling. Then we might get a roll and then the GM will decide both the outcome and the consequences.

This is also tied to the way settings are presented in these two play styles. In OSR the world is what the GM has decided it should be (possibly with the aid of random generators during prep). The GM can maintain their knowledge of the setting and the setting’s consistency because they have full control of what rules and rulings are applied, and what their effect is.

Apocalypse World meanwhile is pretty explicit that you should leave the detail till later, assume all your NPCs can die at any moment, play to find out how dangerous your Fronts are. This means that when the PCs are successful, their Moves can give them permission to change that world, or add detail in places the GM was instructed to leave vague. This is great and it really focuses stories on the PCs and their actions, but it is not how OSR games work.

So can OSR and PbtA be combined? Yes, absolutely, but I don’t think it’s possible to have a game which feels like both it’s inspirations. Certainly Freebooters and Vgabonds didn’t feel like OSR to me. World of Dungeons comes closer because it is so loose and without Moves the players aren’t given much control beyond their characters, but I know that some people don’t feel that it still PbtA.

I wonder if World of Dungeons can simply be played either as a PbtA game or as an OSR game because it is so light that you can run it however you like. And if that’s the case, I wonder if anyone has ever managed to run it like both at the same time.


“Rulings, not rules” is actually a pretty complex idea, and can mean a lot of different things.

Some people use it to mean, “we’re not bound to a written rule set; instead, the referee judges every moment as an individual case.”

Some people use it to mean that we play “fiction first”, and our understanding of “what would happen” always trumps whatever a given ruleset suggests.

Some people use it to mean, “whatever the GM says, that’s how it goes” (like Rule Zero).

Some people use it to mean that we’re using an incomplete rule set, and accepting from the start that it’s not going to cover everything we need.

Some people use it to mean that each ruling acts as a precedent for future rulings, and so, like precedent law, we build up the actual rule set in use over time.

Some people use it to mean that the group, as a whole, is responsible for figuring out how a fictional situation is resolved.

Some of these make sense in a PbtA context; however, most do not.

Is making an MC move like making a “ruling”? Well, it depends on what principles the MC is using. Is she trying to create drama and action? Trying to describe the most reasonable resolution, given the fictional situation? Or trying to establish a precedent for what she will do on a miss in future situations?

It depends. PbtA games don’t specify which, but most people tend to play them in the first mode I’ve described; it’s a fun way to play and a natural fit for the ruleset. However, it’s definitely not OSR.


Only addressing the first part, adventure and setting design seem another large topic here, but the core mechanical difference might be more important?

This sounds rather like the distinction I make above between esoteric and unitary systems? Is there always a move in a PbtA system and/or is fitting a decision into existing moves a feature of play? Do moves have specific predetermined (say future mechanical bonuses or effects) outcomes?

The specific space in the playstyle here (whatever its source) for that ad hoc GM decision sounds like it implicates the unitary/esoteric system mechanics, while the lack of preference for fitting resolutions feels very different then having a move set. The second seems like a gamified resolution mechanic (player explains how action fits move mechanic) while the first seems simulationist (character does X, GM decides how it fits into play and what resolution mechanic).

Obviously, not every decision in play follows these distinctions in a pure form - classic players may want to fit character actions into various mechanics and state this, while PbtA MCs and players may want to and new moves, or alternate mechanics to handle novelty.

Again I don’t want to say you can’t swap rules between the system a profitably, but I question if a meaningful hybrid is possible because intent & playstyle are seeking to do different things.

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(Sorry for reposting, new to the forum and I accidentally replied to a particular person in the first post) I’ve noticed that the thread has become very focused on one very particular issue of game design (fictional positioning and the way that it emerges differently in the two designs), but I’m wondering if the conversation would benefit from expanding our scope a bit?

In particular, I was thinking about the way that the two designs tend to imagine the fictional spaces of the game world. It informs fictional positioning, I admit, but I don’t really think it’s 100% reducible to that. The blog you posted gets at that issue a bit APM (sorry, @Jeremy_Strandberg actually). In OSR, there’s the assumption that people and things have an existence prior to the player seeing them while PBTA games tend to treat the fictional space of the world more flexibly, with the GM and players having more permission to add to the space when narratively interesting.

You see the difference pretty clearly in how the two genres treat the issue of seeing things. Notice rolls and searches in OSR can be made even when there’s nothing to see. Poor rolls can result in the player simply not seeing or finding anything even when there is something there to find. A guard that the players fail to see can still take action against them, for example. While PBTA does encourage the GM to think off screen in the form of threats, it generally chooses to present a world that largely exists in the field of the player’s view and doesn’t strongly persist outside of it. Players simply see things if they are there to be seen and the various spins on examine rolls that you see come out of PBTA games tend to encourage the GM to add to the scene rather than reveal to the player what is there. I’m thinking back to one of the grandparents of PBTA, Donjon, as an exaggerated example. In Donjon’s favorite example of how a search roll worked, the existence or non-existence of a secret door would not be determined until the player made the roll and while PbtA games tend to refine that idea a bit, the ethos that player action always adds to the scene is still there in the design. The fictional space tends to emerge from player action in PBTA rather than being the set in which player action takes place as in OSR.

Correct me if I’m off-base, but I had actually seen the Forged in the Dark genre as something of a combination of the two design philosophies in relation to how they handle fictional spaces. Certainly, on the level of the scene, FitD is STRONGLY a PBTA subgenre for all intents and purposes. It’s structure of faction play, however, reminds me of the interest that OSR games take in simulating a larger world that persists outside of player action. I’m definitely an outsider to OSR, however, so this connection may be a bit tenuous for people who are more tapped in to the genre. Even taking into account faction play, FitD is more PbtA than OSR, but I’m wondering if it might be a more productive example of how the two genres could be synthesized than focusing on the granular level of the scene and the action roll or trying to achieve a perfectly balanced synthesis of the two.


One way in which PbtA is fairly similar to OD&D and other OSR games is related to something @Gus.L said earlier:

Unitary v. Esoteric mechanics is a distinction on how mechanics are resolved.

It’s true that PbtA uses a 2d6+mod roll for many things, but I actually think this is a way that it’s similar to an OSR system (as opposed to GURPS, White Wolf, Fate, or other systems).

Each “move” in a PbtA game is sort of an ad-hoc ruling with a simple table look up (and some other subsytems) which are lightweight enough that most GMs end up inventing their own (or porting them between systems). To me this is exactly the kind of hybrid, organic approach that OSR groups use to fill in the “gaps” of OD&D or to pick and choose which parts of AD&D 1e to use or ignore.

However, I think there’s a major difference that hasn’t been mentioned so far: the stance and role of the GM. Maybe the best way to make this point is by analogy to different legal systems.

In an adversarial legal system (used in U.S. criminal law, English common law, etc.), the judge is expected to hear evidence from the prosecution and the defense, and to rule impartially on issues of law. The judge is expected to be fair to both sides and not push the case to particular outcomes.

In a nonadversarial legal system (also called an inquisitorial system), the judge is actively involved in investigating the case and establishing the facts. They work with the prosecutor to present the case. While the judge is still expected to be fair, they are expected to form their own opinion of the case, which will be reflected in their ruling.

(In this analogy you could imagine the threats, monsters, and challenges playing the role of prosecution and the players playing the role of the defense.)

This is the place where OSR and PbtA tend to part ways. Despite jokes about total party kills, OSR GMs are expected to impartially interpret the rules, to make consistent rulings, and to see where the dice lead them. When bad things happen to the PCs the understanding is that this is due to the uniform application of the GM’s rulings (and often the game’s explicit rules) and that the GM did not “choose” the outcome. In some ways the GM is indemnified from being personally responsible for the outcome.

By contrast, in PbtA, the GM has relatively little structure or guidance around how and when to take hard moves, which hard moves to take, and how hard to make them. While players do understand that making these hard moves is part of the GM’s job, the GM has far more discretion in when and how to act. This also means that there is less guidance, and it can be more challenging for a GM to demonstrate fairness and consistency in their rulings. In PbtA GMs are also specifically tasked with pursuing an agenda, not necessarily against the players, but which certainly prevents them from fulfilling the kind of impartial referee role that many OSR games envision.

I think this is the widest gulf between OSR and PbtA play styles. While I can’t prove that it’s impossible to bridge the gap, I’m not convinced that trying to “split the difference” here would lead to an effective philosophy.


If you want to discuss something different I’d recommend creating a new topic.

Yes, I think the design philosophies can be combined, and I think the Principia Apocrypha is a nice way to frame OSR play in terms of PbtA principles. I’d even go so far to say that OSR and PbtA play styles are more similar than they are different (at least the way I’ve played and run them), the main differences between them being matters of presentation and philosophy. To folks who aren’t dialed into industry and theory discussion as much as forum regulars are, our debates on this look like an agnostic’s take on Protestant ministers fervently debating whether we are saved by “faith” or by “grace alone.” Just to dispense with some myths about PbtA games proffered for why these differ (including in this thread):

  • “Players have more narrative control.” Explicitly true in some PbtA games, though not in all, and no more true in Apocalypse World than in OSR games I’ve played. (Players have input in the world in the first session, but then the MC is instructed to respect their prep.)
  • “Things don’t exist in the world until the GM interprets the dice.” Maybe true the way some people play them, but I believe this is based on a misreading of Apocalypse World’s “play to find out.” It’s not what Sage Latorra intended for Dungeon World, at least. See Quantum Ogres vs. Read a Sitch? for more discussion.
  • “Everything is handled according to a single resolution mechanic.” Not even true in Apocalypse World. Roll 2d6 + stat is the most commonly used resolution mechanic, but you also have simple if/then statements, specific examples of “you can have that, but you need to do this” with no roll required (like the Savvyhead’s workshop), added layers of resolution via expenditure of currencies (“hold”), etc. This myth breaks down even more when you consider any PbtA game that doesn’t use 2d6 + stat, like Undying, a diceless game that uses blind bidding rules for combat, a simple “spend 1” for supernatural powers, and “choose as many as this stat” for other moves.
  • “PbtA games don’t let the GM make up stuff.” Apocalypse World and Urban Shadows offer quite extensive guidelines for making your own custom moves, and—“rulings, not rules” notwithstanding—there’s no shortage of comparably carefully considered optional rules and modular subsystems on the OSR blogosphere. But this last item does point toward where these traditions do differ, to my mind.

If there’s a deeper seated formal or philosophical difference, though, I see it as in PbtA games’ implicit assumption that the rules matter very much, and (certain) OSR games’ often quite explicit assertion that rules are incidental, or not where “real” play mostly happens. Specific rules of dice and points in OSR games are often regarded as just as modular as the adventures you run with them, offered as a toolkit to select or reject pieces from as you like. PbtA games more often (but again, not necessarily) have purposefully interlinking moves and systems, where just ignoring an entire portion of the rules can pretty radically change the game experience and leave you wondering what the hell the designer was thinking. I think this might be less the case in PbtA games that I’d argue are also OSR games, though: World of Dungeons 1979 is pretty easy to tinker with, and my read of Freebooters on the Frontier suggests that while it’s certainly purposeful in its design, part of that purpose includes being approachable as a hackable OSR rule set. (But I’m curious what @jasonlutes might say about that.)

Ultimately, I think the biggest distinctions between PbtA and OSR gaming are cultural—the terms we use to describe them, the people designing them and playing them, the expectations baked into them—but there’s a lot of cross-pollination in this hobby. I’m always excited to see people trying new games and letting those experiences inspire whatever they work on next.


Though even that isn’t necessarily clear-cut; I love Vincent’s breakdown of how Apocalypse World uses concentric design; while AW isn’t exactly modular, it consists of modules arranged in such a way that they can be lifted out/forgotten pretty easily.


This discussion is very interesting and touches on topics I’ve idly wondered about myself and it’s helping my clarify my own thoughts in a very useful way.

As JasonT says, I think there are big overlaps and that it varies from game to game how big that overlap is, but one area where OSR and PbtA are very close is in “play to find out what happens”. Both OSR (as I understand it) and PbtA (ditto) explicitly tell the GM to not plan for specific outcomes but let the story develop through play. However, I think there’s also a meaningful difference here, in that the story in ORS is simply “the things that happened” which may or may not be meaningful, poignant, or coherent, while most PbtA games encourage those qualities in the emergent story, directly or through playbook design.

I also think Apocalypse World explicitly encodes many things that were assumed or emergent in early D&D play (as I’ve understood it) without being part of the rules. For example, your character will either die or retire to safety, and you may have multiple characters (though typically you’d only play one at a time, from what I’ve gathered). In OSR play, this is a natural effect of an ongoing campaign with a rotating gruop of players where an individual character has very little importance; it’s the world that lives on, not the characters.

However, this may be me drawing too fargoing conclusions from superficial similarities.


I’ve been trying to formulate to myself the difference in approach to rules between OSR and PbtA games (again limited by my own understanding of what those entail), and the closest I’ve come so far is this:

In an OSR game, the rules are primarily the rules of the physical world. They aren’t absolute, since the GM decides when they are applied, but they give a general sense of how the physical world functions and how the player characters can interact with it.

In a PbtA game, the rules are primarily the rules of the story. This is why PbtA is so good at genre emulation: It looks at the kind of story you’re trying to tell and says “Hey, let me help you with that”.

I think this goes back to my previous point about playing to find out what happens. In an OSR game, you may be playing a kind of story in the broadest, most general sense of the phrase, like “this game produces a story about adventurers in a fantasy world”, but being more specific goes against the OSR meaning of playing to find out what happens which places the focus of interest on how the player characters interact with the physical world and the consequences of those interactions.

In contrast, I think the typical PbtA game is about interacting with the world as a set of story elements. (I should note that I think these approaches exist on a continuum rather than as discrete points.) Very roughly, in an OSR game a dragon is a threat because of the nature of the dragon while in a PbtA game a dragon is a threat because it is a threat that has taken the shape of a dragon, if that makes sense.

If a game is a machine, then the goal of an OSR game is for that machine to accurately represent the physical world where the game is set, and playing skilfully is to learn how the physical world as represented by the machine functions so you can manipulate the machine in order to get the outcomes you want (typically success in your in-game mission and/or an increase in power for your character). Meanwhile, the goal for a PbtA game is for its machine to accurately represent the kind of story you’re trying to create, and playing skilfully is to learn how the story as represented by the machine functions so you can manipulate the machine in order to get the outcomes you want (typically an emotional experience and/or the satisfaction of a story that fulfills expectations in some ways and refutes them in others).

I started this post with what felt like a solid thought but I kept writing into what feels more like loose speculation so take it for what it’s worth.


One more thing. I think it’s fairly easy to import mechanisms back and forth between OSR games and PbtA games without bringing the play approach over.

For example, Beyond the Wall and Other Adventures has a mix of OSR and PbtA styles in its rules. The playbooks are a bit PbtA in form but most of what’s in them is more like an OSR game with a lifepath system, the village creation is very PbtA, and most of the the resolution mechanisms and the rest is very OSR.

However, I still think of it as more of a PbtA game in approach because it sets out to tell a specific story. It’s not “this game tells the story of a group of adventurers from a small village”, it’s “this game tells the story of how a group of children try to protect their village from the invading goblins” (or whatever playset you’re using). To me, that’s a much more PbtA approach to making a game than OSR.

(As a sidenote, there’s another thread here about adapting Beyond the Wall to other mechanics, and I’ve had that idea too. I adore the playbooks, the village creation, and the GM prep, but I feel like the rest of the game is fighting against what those parts are trying to do, or at least not helping it. My thought was to convert it to Fate but I don’t know Fate well enough to pull that off myself.)


That’s interesting because I feel like Beyond the Wall still very much plays like an OSR game. Some quite PbtA set-up, but as soon as the GM asks “What do you do?” it’s OSR all the way. At least it is the way I run it.

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Hm, yes. What I should have said is probably that to me it feels like BtW wants to be a PbtA game, but that may be my own biases speaking.

This has popped up back in my mind because of the setting similarities between “Into the Odd” and “Blades in the Dark”, and I’m thinking right now about how to merge them together.

ItO has an extremely lightweight approach to rules (far more than most other OSR games). On the other hand, the default setting (Bastion) has a LOT in common with Doskvol. And ItO has some extremely nascent rules for running detachments or enterprises and conflicts with other such organizations (factions, in BitD).

This isn’t to say they’re about the same things: one is about venturing into dungeons and recovering ancient bits of “arcana”, and the other is about heists and crime. But I feel like those things are not all that different, and the ideas behind the game aren’t that different either.

From the “Into the Odd” product listing on DTRPG:

Into the Odd contains everything you need to create a character and explore an industrial world of cosmic meddlers and horrific hazards. This is a fast, simple game, to challenge your wits rather than your understanding of complex rules.

You seek Arcana, strange devices hosting unnatural powers beyond technology. They range from the smallest ring to vast machines, with powers from petty to godlike. Beside these unnatural items that they may acquire, your characters remain grounded as mortals in constant danger.

And from the “Blades in the Dark” SRD page:

Blades in the Dark is a tabletop role-playing game about a crew of daring scoundrels seeking their fortunes on the haunted streets of an industrial-fantasy city. There are heists, chases, occult mysteries, dangerous bargains, bloody skirmishes, and, above all, riches to be had — if you’re bold enough to seize them.

So maybe “Blades in the Odd” could be a thing…


If someone hasn’t already made a dungeon crawl hack Forged in the Dark, they damn well should have.


Indeed. I give you Blades Against Darkness.


And also Into the Dark


Thank you both for those links!