OSR, PbtA and the Mixed Success

I’ve had a question sitting in the back of my mind for the longest time. I started out with Dungeon World before getting into the OSR, lured in by Sage Latorra’s assertion that 'If you started playing D&D as a kid, it runs more or less exactly like how you imagined a fantasy game of exploration and adventure should run.

I stopped playing it and switched to the OSR, because of DW’s focus on placing the PC’s narratives first, and shaping the world around them. (To be clear, there’s nothing wrong with that)

My question was about my favourite Dungeon World mechanic, which is also the one at the heart of PbtA: the Failure/Mixed Success/Success roll. Certainly it stretched me as a GM more than any other mechanic I’d tried up till then.

Thing is, integrating ‘Mixed Successes’ has never really taken off in OSR-influenced games. That’s understandable in the retro-clones, but I notice even as OSR games have innovated with things like Hazard Dice, or overloaded Encounter Dice, or Inventory Slots, dice rolls still seem largely binary pass-fail. I’m aware of games like Brindlewood Bay, Beyond the Wall, World of Dungeons etc, but it seems (to me!) that these games don’t get much discussion in OSR spaces, and they exist within the ‘Storygame’ category for some.

So: is there something I’m missing? Is the ‘Mixed Success’ mechanic counter to fundamental OSR play loops? Or is this just fall-out from the OSR-Storygames War that went on a few years ago?


It’s been there the entire time with DM Rulings/narration, but it crops up in more obvious places like the Reaction Roll and the Cleric’s Turn Undead table (which also makes a handy substitute for Thief Skills, just use Dungeon Level as the HD). In a way, the vast majority of Damage rolls are also “Partial Successes” if you squint.

The Reaction Roll bell is likely the direct ancestor here for PbTA games, and when I need to go ad-hoc I’ll often grab 2d6 and just roll on it. I use it for determining the Weather for example, but it’s a great way to judge the outcomes of just about anything with that lovely graduated success :slight_smile:.


That’s interesting to me, since I’ve recently come to see the Attack Roll and Damage Roll as needless redundancy. I’ve had more than one instance come up where a PC rolls to hit, is thrilled…and then gets that deflating ‘1’ on the damage die.

The reaction roll is a great example of ‘mixed results’ being part of the OSR! I also do think some GMs play with Mixed Successes by negotiating using a Fortune Die (if you try this, I’ll roll a d6 and we’ll see what happens…) but I wonder why it hasn’t caught on as a resolution mechanic.


“1” on damage die is kind of what I’m talking about with the whole “damage rolls as partial success” thing, but I agree that it can be very de-protagonizing. One thing I’ve done in the past to mitigate is to have “1s” allow weapon effects (stuff like tripping, disarming, knocking someone back, etc) or even just have “1s” explode in a way: Roll the next highest dice and add…upper bound is d20 if you keep rolling ones. This little hack made the player’s crave ones :slight_smile:.

“Success” in a damage roll is reducing that one, final, fatal hit point. Everything else is technically “partials” :slight_smile:

I think one of the cornerstones of this style of play for me is only engaging the Dice when something is really at stake and there are severe consequences, hence the rather binary results of most of the subsystems: Combat is dangerous, Abilities are somewhat unreliable, etc. Player Skill can help you navigate the game without having to leave your outcomes up to the fickle mistress that is the dice, so I tend to lean on that pretty heavily. The answer isn’t in the rules as written or on the character sheet. The conversation and negotiation as we narrow the gap in our fictions and expectations here is where the compromise and give-and-take takes place. “You can try that, but X is a possibility” etc. :slight_smile:.


It hasn’t really caught on, because it’s been implicitly there all along. Y’know, when someone rolls incredibly well or incredibly poorly (not necessarily natural 20 or 1), the GM narrates the outcome differently. Well, whatever extra detail is included is now there in the fiction, which the players (and enemies) are able to leverage.

The idea that it needs to be codified isn’t really new (see Marvel Super Heroes from 1984), and one part of me gets it. However, the reason PbtA games include it is solely to further genre-appropriateness by escalating the conflict. That reasoning, to me, seems antithetical to what traditional game systems are: simplified physics engines.

Granted, not everyone views them that way, and of course genre emulation and gaming conventions do influence OSR games and my own GMing as well.


This is super interesting! Has there been anything written about this?


In case this is an interesting tidbit to contribute: the reason why there are damage rolls and hit dice, as opposed to flat rates of damage, was to make player death less likely! During Dave Arneson’s Blackmoor game, one of his players ragequit the game because his character was killed on one dice roll (the most immediate source I could find). They switched to using dice rolls for damage, along with a randomly-determined number of hit points.

The effect of this was that, assuming they used d6 for HP, the average character basically has a 50/50 shot of being killed by a successful attack (damage = d6). I’m almost certain this is why HP was bumped up to d8 in later D&D–to slightly increase the chance of survival to somewhere between 67% and 83%.

I always thought it would be cool to see similar “allowances” added to non-combat situations, basically adding a dimension of mixed success in the same way. :slight_smile:

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I haven’t formally written anything up about it or anything blog post-wise (here’s a very ancient post I did about Thief Special Abilities), but that Turn Undead Matrix is super handy for a lot of things when re-contextualized. I like to tinker, and it seems a lot of people are dissatisfied with the standard resolution for Thief Abilities. :slight_smile:

The Matrix is neat mainly because there’s an opportunity to tie in “Task Difficulty” as well as taking into account “Character Level.” The bell-curve is less swingy than the d%, so I think it makes for more competent Thieves (provided they don’t stray too deep…though it does bake in a little bit of “over achievement” which I’m fond of).

My reasoning for “deeper the dungeon, harder the hazard” is just for ease at setting the Task Difficulty, but you could easily just assign each Trap/Lock/Wall a level/HD (or even just roll randomly on the fly…HD is generally already available for some…like “Sneaking past a foe” by just using their HD).

Partial Success is also there. Take Traps for instance: if “D” disables and “T” delays an effect you have some nice tension and those degrees. I like how the matrix is “player facing” moreso than the old “mother may I find a trap?” problem or taking the dice outta the player’s hands to roll for hidden info. If the Thief can size up the danger (obtaining the level/HD somehow), then they know what they need to roll and can see if/how they fail.

You could even have a Thief pick an ability and Specialize (basically allow them to treat themselves as a Cleric a level higher, or something similar).


This is interesting! I don’t personally change outcomes based on degree of success, though I might call for Fortune rolls in particular situations. I guess a mixed-success mechanic codifies it and makes it accessible to players explicitly. If an OSR ruleset explicitly came out and said ‘if you roll over/under by X, the result is not as good as you hoped’, would that still count as ‘OSR’ (whatever that means these days)?

I hear you on genre emulation, and I do agree. The PbtA dice roll system is designed to explicitly create tension. I do wonder about the assertion that traditional game systems are ‘simplified physics engines’. I think that philosophy is evident in earlier retroclones, but as the OSR morphs and mutates through newer rulesets, do rules to introduce tension have a place at the table?

In one sense, the regular wandering monster check has that function in trad games too. I’ve read mechanics like the Hazard Die or the Overloaded die, or (I think it was Necropraxis’?) Tension Die that are designed to escalate risk in the dungeon.

This is an interesting discussion! Thanks for your ideas

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Great discussion and a lot of great and informative ideas and opinions.

I’ve been playing a lot of Blades in the Dark, a PbtA-adjacent game (with many OSR elements IMO) that has a “success with consequence” tied explicitly to a dice result range. It is the consequence (different from a “partial success”, which in Blades has a disctinct mechanic – clocks) that drives the narrative forward in an interesting way.

I’ve come to realize that in a single roll, a success with consequence has the same “narrative” value as a straight fail or miss. If you just fail the action, you gain no narrative advantage or disadvantage, but if you succeed with consequence, it gives you an advantage and a disadvantage, which gives you an equal position (+1-1=0), but perhaps a more interesting one.

So, with any binary roll in an OSR game, instead of measuring a straight success/fail result, it can be ruled that the action is absolutely successful, but the roll determines whether there is a complication or not.

Referees in OSR games already use this kind of ruling with some rolls, like “open doors” or thief skills, but they could be used more widely. Of course, this is best left in the domain of situational rulings, which is a feature of OSR.


As Ynas Midgard remarks, degrees of success are often used “unofficially” by DMs. I would also make the case that damage dice represent degrees of success.

But they have been around in non-D&D games since 1975. Take Tunnels & Trolls, published that year. Combat in T&T is a contest of dice, not alternating shots (a wargame mechanic for miniatures with ranged weapons firing at each other across a table). In T&T, the difference between the totals of the antagonists is the damage done by the winner on the loser. This is precisely a matter of degrees of success, and success in one round increases your chance of success in the next as you wear your foe down. Similarly, T&T saving throws are according to “levels” of difficulty. If you overshoot the level of success needed, GMs usually narrated the success as, well, more successful.

The Fantasy Trip (1977-1980) and its successor, Man to Man (1985) > GURPS (1986), has critical successes and failures the odds of which vary according to your ability in the thing tested. These are heirs of T&T in several respects, including contests of abilities between opponents. The notion that a good successful roll is better than a bad successful roll is explicit. Whenever I ran GURPS (a long time ago…), the numerical degree of success always mattered.

Any time there are modifiers to checks for variation in circumstances or challenges, there are, in effect, degrees of success.

A lot of interesting gaming rules and ideas have been lost and forgotten as D&D-based and PbtA games have crowded everything else out of view. “Old School” is highly selective and the new stuff is a reaction to 5e and “Old Scool.”

I think that “success with consequence” is a nice idea. It sounds exactly like “critical successes” that so many games have used over the decades.


I suspect a major reason this isn’t more prevalent is only that a system with “success with complication” hasn’t hit it huge in this community. Dungeon World was very successful but I think it still leans too bombastic and narrativist for many folks’ tastes here. Diogo Noguiera’s Solar Blades & Cosmic Spells includes a different take on the mechanic – while that is generally well-regarded, I wouldn’t say it was a breakout hit and I don’t see too many clones of it.

Freebooters on the Frontier is a more grounded fantasy PbtA - I think the first edition flew under the radar but I’m hoping the upcoming 2E will do the same for its popularity as did Black Hack’s second edition.


It’s funny— World of Dungeons is a “Powered by the Apocalypse” game because of the dice mechanic, but I think a lot of people may miss that it’s also (perhaps even more so) an OSR game that happens to have a partial success result. It’s easy to miss this because the faux-retro clone aesthetic makes it look like a joke, but hey, we’ve got super simple rules that leave a lot of room for rulings, gold as XP, traditional ability scores, and a distinct lack of other PbtA staples like “basic moves” that try to push the story in a particular direction.

I’m also trying to build a series of OSR microgames with partial success in 2400 (inspired originally by luck rolls in Electric Bastionland), but I’m remembering as I play it what pulled me back to simple yes/no resolution in the first place: This is more work for the GM. I think it’s more important to have that leeway in a game like this one, which lacks HP and damage rolls, but as noted above, those things do the duty of partial success (and leave less to GMs to figure out) in other games.


I have been using d20 core resolution systems with explicit partial success for a while now when I run OSR type games, and my Hexagram rules use this sort of resolution for all ability checks, attack rolls, and so forth. No full release exists yet (Hexagram is more or less the version of my OD&D house rules that has drifted into new game territory), but I have a few posts which outline similar methods:

Even when I run something closer to B/X, I pretty much always replace traditional Vancian spell casting with some form of roll-to-cast system, which is basically success = intended consequence, partial success = intended consequence + unintended consequence, failure = only unintended consequence, and critical failure = catastrophe. This fits the thematic “sorcerer’s apprentice” vibe I love to see with magic. For the choice of mechanic, either a save versus magic or an intelligence check works well, depending on how much you prefer to emphasize improvement over level (use saves) or adventurer abilities, without needing to introduce any complicated new rules. “Fail within 4” is a good threshold for partial success I find, being easy to remember and reckon in real time. So, for example, if the save versus magic target number is 16, 12 or higher results in partial success, 16 or higher in full success.

The overloaded encounter die/hazard system also entails a set of graduated outcomes, though unconnected to direct adventurer ability scores or stats. 1 represents the greatest introduction of chaos or uncertainty into the events of play, while 6 represents the most certainty.

Not to say I have this all figured out, but if you want to experiment with more formalized partial success mechanics while keeping to a recognizable OSR type framework, there might be something you can take away (and I have accumulated a lot of anecdotal play testing experience from running these systems).


Oh, and here is a post explicitly about hacking partial success magic into an otherwise standard OSR/classic type game:


While it may not be OSR, Burning Wheel has a section in it that calls out the partial success. They have clearly written out success with a cost and it is a rule/section that follows me in every game that I play.

The example that they use is a thief picking a lock:
Way 1: I roll to pick the lock on the door, roll and fail, keeps trying till they get a success.
Way 2: I roll to pick the lock on the door, roll and fail, dm either stops play, or gives it to them.
Way 3: I roll to pick the lock on the door, roll and fail, you unlock the door - as you hear the satisfying click of the tumblers falling into place you hear a voice behind you, “And what do you think that you are doing here?”

So success in the the final case would of been, I want to pick the lock before the guards get here. Meaning failure would be the guards finding them. Whether the door is opened or not is dependent on what the story/game is needing to happen. They call it task/intent.


I think an easy way to do partial successes with combat in an OSR game is have anything that wouldn’t hit an unarmored target be a failure, anything higher than that but does not meet the target’s AC be a partial success, and anything that meets the target’s AC or above is a full success.

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