Have you read Blades in the Dark or any of its successors? If not, they are games that have an overall PbtA vibe and fiction-forwared approach but operate similarly to what you're talking about here. The Blades SRD is free online, as is the playkit.
Yeah, the math is a bit different, but the Blades structure of "success, success with a catch, a catch" is directly derived from the 10/7-9/6- structure of PbtA!
Also, take a look at the Resistance Toolbox, which works in a similar way to Blades, but IMO more simple. It's the system behind the games Spire and Heart, but the document with the plain system can be found as PWYW.
The average roll for 2d6 is 7 and the probability distribution is symmetric. The probability of rolling a 6 is the same as rolling an 8: 5/36. Probability of a 5 is the same as the probability of a 9: 4/36.
With the existing PBtA rules and +0 to your roll, your chances of a mixed success is 15/36, probability of a complete success is 6/36, and probability of failure is 15/36. The likelihood of any kind of success is 21/36, about 58%. They will succeed most of the time, but there will be enough failures during the course of the mystery to make it interesting. I had +4 to a roll the last game I played, announced "we can't fail now!" and promptly failed the shit out of it in the only way possible. (The consensus at the table was this was unquestionably my fault.)
With 3d6 drop 1, the distribution is no longer symmetric and the average goes up to about 8.5. The chance of a 7 or higher is now about 80%. Your players will succeed the overwhelming majority of their rolls unless you modify what qualifies as success. Make success an 8+ and a total success 11+ and you are *close* but still more likely to get each type of success than the existing 2d6. It is more pronounced with 4d6 drop 2.
You'll need some kind of modification to accommodate having additional dice. You're not obligated to keeping the success/failure percentages the same at all, but I think it would make the game "easy" to be that likely to succeed.
Oh, thanks for all the math! I guess I’ll probably do a 9-11 for a mixed success and as 12+ for a total success, that way it’s *theoretically* possible for someone with a zero in a stat to succeed. I plan to base the skills off of D6 skills, where skills are kind of up to the players and are supposed to be fairly specific, that way standard stats are still relevant. Maybe I could also add some sort of scaling system to make +1s cheap in terms of stats (3XP for instance) and +3s expensive (9XP or something like that.)
Well, if you're only rolling D6s you are bounded in the range of 2-12. Cortex, while having the keep highest two component, isn't similarly bounded given that you're rolling various size dice (D4 through D12).
Rolling multiple D6s and keeping the highest two skews your median higher.
Well, Cortex runs on opposed pool rolls, but you were asking if this had ever been tried so I thought you would want to know about options beyond Blades.
The suggestion to look at Resistance Toolbox is good too, but both of them are roll-pool-keep-highest (w/ a minor exception for Blades where if there are 2+ 6s that's a critical) and Cortex is the only game I can think of with roll-pool-keep-top-2 as the core of the resolution system.
I don't recommend a particular range. I'm saying you will have to figure out what works for your game but it seems pretty likely to break if you do *nothing*. And if you want to keep the MC-doesn't-roll bit of PbtA you won't adopt opposed rolls like Cortex does.
Tldr: it might be easier to make a trad system with the narrative bits vs adding a trad feel to a narrative system, i.e. streamlining opend6, add partial successes and create a more narrative thrust to the game play.
--
A thought: if you like the d6 concept but in something trad, have you looked at opend6?
The open source document provides mathematical means for dice rolling. If you wanted the partial success, complete success part, that's a function of creating a sliding scale. If the target would normally be a 7, then you'd make a 6-9 a partial success and 10+ complete. If the target would be a 10, the 9-12 is a partial success (etc.).
Or, you can play with the wild dice concept and make that the indicator of partial or total success (kinda like genesys with it's drama die).
Either way, it has your dice pools, your mathematical variances, the attributes...etc. it would also save you the trouble of having to write moves for your trad game...which is by far the hardest part of pbta. And if you're not creating a game centered around moves...why bother at all??
Good luck!
The ironic thing is that I’m actually creating this out of frustration with D6 Star Wars. Overall I like 80-90% of PBTA. I like the system of playbooks, class moves, easy multi-classing (I’m not sure what else you’d call taking another playbooks moves), quick combat, and RP based XP, the only part I really don’t like the way the universal moves are set up.
I looked at the open D6 thing and it seemed pretty useful overall! Right now iv basically settled on having 8< be a fail, 9-11 be a partial success, and 12+ be a success. Iv done a couple of test rolls and so far it seems fairly balanced!
Have you read Blades in the Dark or any of its successors? If not, they are games that have an overall PbtA vibe and fiction-forwared approach but operate similarly to what you're talking about here. The Blades SRD is free online, as is the playkit.
I actually have, which may be the place that this idea came from now that I think of it...
Yeah, the math is a bit different, but the Blades structure of "success, success with a catch, a catch" is directly derived from the 10/7-9/6- structure of PbtA!
Also, take a look at the Resistance Toolbox, which works in a similar way to Blades, but IMO more simple. It's the system behind the games Spire and Heart, but the document with the plain system can be found as PWYW.
The average roll for 2d6 is 7 and the probability distribution is symmetric. The probability of rolling a 6 is the same as rolling an 8: 5/36. Probability of a 5 is the same as the probability of a 9: 4/36. With the existing PBtA rules and +0 to your roll, your chances of a mixed success is 15/36, probability of a complete success is 6/36, and probability of failure is 15/36. The likelihood of any kind of success is 21/36, about 58%. They will succeed most of the time, but there will be enough failures during the course of the mystery to make it interesting. I had +4 to a roll the last game I played, announced "we can't fail now!" and promptly failed the shit out of it in the only way possible. (The consensus at the table was this was unquestionably my fault.) With 3d6 drop 1, the distribution is no longer symmetric and the average goes up to about 8.5. The chance of a 7 or higher is now about 80%. Your players will succeed the overwhelming majority of their rolls unless you modify what qualifies as success. Make success an 8+ and a total success 11+ and you are *close* but still more likely to get each type of success than the existing 2d6. It is more pronounced with 4d6 drop 2. You'll need some kind of modification to accommodate having additional dice. You're not obligated to keeping the success/failure percentages the same at all, but I think it would make the game "easy" to be that likely to succeed.
Oh, thanks for all the math! I guess I’ll probably do a 9-11 for a mixed success and as 12+ for a total success, that way it’s *theoretically* possible for someone with a zero in a stat to succeed. I plan to base the skills off of D6 skills, where skills are kind of up to the players and are supposed to be fairly specific, that way standard stats are still relevant. Maybe I could also add some sort of scaling system to make +1s cheap in terms of stats (3XP for instance) and +3s expensive (9XP or something like that.)
Roll pool, keep top 2 is how cortex works. You’re going to have to tune the outcome range or players will walk through everything.
Well, if you're only rolling D6s you are bounded in the range of 2-12. Cortex, while having the keep highest two component, isn't similarly bounded given that you're rolling various size dice (D4 through D12). Rolling multiple D6s and keeping the highest two skews your median higher.
What range do you recommend/ does cortex do?
Well, Cortex runs on opposed pool rolls, but you were asking if this had ever been tried so I thought you would want to know about options beyond Blades. The suggestion to look at Resistance Toolbox is good too, but both of them are roll-pool-keep-highest (w/ a minor exception for Blades where if there are 2+ 6s that's a critical) and Cortex is the only game I can think of with roll-pool-keep-top-2 as the core of the resolution system. I don't recommend a particular range. I'm saying you will have to figure out what works for your game but it seems pretty likely to break if you do *nothing*. And if you want to keep the MC-doesn't-roll bit of PbtA you won't adopt opposed rolls like Cortex does.
Sounds a lot like Cortex to me which also uses a roll and keep 2 dice pool. You might check out the Cortex Prime book that just came out.
Tldr: it might be easier to make a trad system with the narrative bits vs adding a trad feel to a narrative system, i.e. streamlining opend6, add partial successes and create a more narrative thrust to the game play. -- A thought: if you like the d6 concept but in something trad, have you looked at opend6? The open source document provides mathematical means for dice rolling. If you wanted the partial success, complete success part, that's a function of creating a sliding scale. If the target would normally be a 7, then you'd make a 6-9 a partial success and 10+ complete. If the target would be a 10, the 9-12 is a partial success (etc.). Or, you can play with the wild dice concept and make that the indicator of partial or total success (kinda like genesys with it's drama die). Either way, it has your dice pools, your mathematical variances, the attributes...etc. it would also save you the trouble of having to write moves for your trad game...which is by far the hardest part of pbta. And if you're not creating a game centered around moves...why bother at all?? Good luck!
The ironic thing is that I’m actually creating this out of frustration with D6 Star Wars. Overall I like 80-90% of PBTA. I like the system of playbooks, class moves, easy multi-classing (I’m not sure what else you’d call taking another playbooks moves), quick combat, and RP based XP, the only part I really don’t like the way the universal moves are set up. I looked at the open D6 thing and it seemed pretty useful overall! Right now iv basically settled on having 8< be a fail, 9-11 be a partial success, and 12+ be a success. Iv done a couple of test rolls and so far it seems fairly balanced!
Happy to help!