Let's Talk About Core Game Mechanics

[Reynard]

A little background: I have been having some recent "wake up call" cardiac situations, which has motivated me to finally take some things off my Creative Bucket list. I have been freelancing off and on in the TTRPG space for 25 years, but one thing I have never done is design my own system. Creating an RPG is definitely a bucket list item. Do this thread is the first in what will likely be a bunch of threads over the next months trying to drill down on a design.

This thread is about core game mechanics: the foundational mechanics of a game that define how stuff gets done in the fiction. they can be simple like "roll a d20 and add a number, compare to a target number" or complex like "build a pool of dice for various abilities, roll, and count the successes then convert those into results." And of course, not all games use dice or randomizers at all, and some games with simple core mechanics are made complex by whatever lays overt them.

I am interested in getting a sense for what people like about a "good" core mechanic. What makes a "good" core mechanic, anyway? What are some of your favorites from various games, and why? Have you ever like a core mechanics but disliked the system as a whole? Vis versa?

As an example of my own, I really like the core mechanic from the Ironsworn games: roll a d6+mods, then compare to 2 separate d10s as target numbers. You can get no success, partial success (beat one of the d10s) or a full success (beat both of the d10s). I do not really if there is a critical system, but I don't think so, nor do I think it needs one. I like that the systems is a little chaotic and unpredictable, as well as the built in multiple degrees of success. One think that could be interesting is to add a Daggerheart "Hope and Fear" style "tenor" element. You could designate the d10s as a Complication die and a Opportunity die. Any time you get a partial success, you further interpret and impact the result based on whether you bet the Complication die or the Opportunity die.

Anyway: core mechanics. Talk to us.

 

[sevenbastard]

Its not logical but I like systems that are roll high and use dice that are not just d6.

I like the bell curve of 2d10. Currently I am working on a home brew with a d8+d12 where you can occasionally get advantage or disadvantage on one of the dice.

 

[payn]

I’m a simple 2D6 man. Add a stat and/or skill mod and go.

 

[...m...]

...i like bell curves with degrees of success; you can simulate it with flat rolls + tables, but three-dice pools handle it automatically if you're willing to step through exotic dice chains for skill progression...

(i.e. 3d4 -> 3d6 -> 3d8 -> 3d10 -> 3d12 etcet)

 

[Micah Sweet]

I've always been fond of the 1d10 system used in AEG's original version of Legend of the Five Rings and a few other systems. You roll a number of d10s (each of which can potentially explode) equal to your trait and your relevant skill against a target number. You can intentionally Raise that TN in order to get enhanced effects on a successful result, but doing that of course increases the risk of failure.

 

[DeviousQuail]

I've recently started playing in a Call of Cthulhu campaign. It's my first time with a d100 roll under system. What I have enjoyed about the core dice mechanic is how easy the adjudication process is at the table. I tell the DM what I want to do. They give me a skill to roll. I have the difficulty of the roll on my sheet and I'm trying to roll equal or below that number. The DM can make it tougher by asking me to roll below half or one fifth my skill number. Lastly, I've got a pool of luck points that I can spend to reduce my roll if I need it at the cost of making my future luck rolls tougher.

Jumping into this has been surprisingly easy for my group. Of all the non-D&D games we've tried I would say it's been the fastest to get started (this would be a lie if we hadn't used an online character creator).

More generally what I like is:
-Quick adjudication
-A way for players to put their thumbs on the scale at a cost
-Few or no reroll mechanics (let's keep it moving people)

 

[Micah Sweet]

I've recently started playing in a Call of Cthulhu campaign. It's my first time with a d100 roll under system. What I have enjoyed about the core dice mechanic is how easy the adjudication process is at the table. I tell the DM what I want to do. They give me a skill to roll. I have the difficulty of the roll on my sheet and I'm trying to roll equal or below that number. The DM can make it tougher by asking me to roll below half or one fifth my skill number. Lastly, I've got a pool of luck points that I can spend to reduce my roll if I need it at the cost of making my future luck rolls tougher.

Jumping into this has been surprisingly easy for my group. Of all the non-D&D games we've tried I would say it's been the fastest to get started (this would be a lie if we hadn't used an online character creator).

More generally what I like is:
-Quick adjudication
-A way for players to put their thumbs on the scale at a cost
-Few or no reroll mechanics (let's keep it moving people)

Yeah, CoC is cool that way. In L5R you can spend a Void point (of which you generally have 2-4 available/day) to add an additional d10 to any roll.

 

[...m...]

...core mechanic can have a big impact on emulating genre: combat as a fail state, tactical flurry, or heroic showmanship...

 

[Scribe]

When I looked at the math with Daggerheart, I came away liking it a lot in terms of the dice used.

I also love the hope/fear as something to drive the action.

 

[billd91]

I prefer core mechanics where the chances of success are relatively easy to estimate for the average player. So I generally favor simpler random number distributions like a flat d20 distribution to more complex ones like 3d6 bell curve for routine and frequent task resolution.