Skill Checks for OSR Games

I can already feel my 7 or 8 readers cringing at the title. OSR style games tend to try to avoid the very idea of skills. From goals of simplicity to theories of gameplay, the concept has a very contentious history. I don't like skill systems in general.  They are cumbersome at best, troubling intrusive and game-breaking at worst. What I've done, instead, is sorta universalize something that was already going on in early D&D and made more explicit how to apply and adjudicate it in various situations. It'll be quick, I promise.

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Background 

Skills have had a long history in Dungeons and Dragons, first as Nonweapon Proficiencies in 1985's Oriental Adventures (although people most associate the term with 2nd Edition), and then developed into their more-or-less current form in 2000's 3rd Edition. Originally they involved a roll-under ability score check adjusted by the rating of the NWP. Later they became their own roll using the universal mechanic of the d20 modified by both the skill rank and the ability score against a Difficulty Class set by the DM.

The big reason that DMs are so leery of skill checks is that that make play more about what is on the sheet than what the PCs do. While PCs want their characters to feel special and different, the addition of explicit skills adds a sizeable overhead to all subsequent actions and leads players to reference their sheet for what is possible rather than their own creativity. So to satisfy the two groups, we would want ways for players to define their characters while leaving in balance the notion that the players are problem-solving, not roll-playing.

The OSR Skill Check

For any risky action, roll 1d6. Risky actions are defined as those which are discrete, having sizeable chances of failure, and which the player has not contrived to render trivial already.

Success occurs on 1-in-6. For each additional factor, the chance increases by 1 in 6:

• The PC has an ability score whose value is a boon. Whether that is some DM-defined better than average for people who don't like ability score bonuses, or a book-defined bonus, or your system doesn't involve specific ability scores but which include beneficial traits that define the character similarly. What about negative ability scores? Ditch 'em. Or recognize that players will always contrive to maximize their use of strengths and minimize their weaknesses.
• The PC has a specific skill that can obviously help. Whether you're going more GLOG-like or are inspired by Warhammer, ditch skill points because incremental advancement is for videogames. Give PCs a couple skills at character creation and let them buy them during downtime.

That's the extent of player character contribution. At best, you can hit 3-in-6 internally. Since both reference binary states (do they or don't they have the trait?), the players should be able to know them without having to check their sheet. Non-sheet factors account for the rest:

• Specifically-applicable tools. An ax to chop down a tree, a crowbar to break a lock, or a creature's language to ask a favor. The tool needs to be something the player has to account for in their inventory or on their sheet. Creatively using tools to solve problems is a core element of OSR-style play.
• Assistance. Is the PC being assisted by someone who is not also making the check? This should refer to active and ongoing help and not to someone having previously set the circumstances.
• Context and Preparation. Are they listening for monsters in a particularly silent area? Have they done their research? Have other factors contributed? This is a catch-all for other external factors.

If the PC manages to acquire all 5, their chance is now 6-in-6 and I'm not going to include an unnecessary roll-twice element like LotFP because at that point you should just give it to them. If they're smart and skilled at orienteering, and they have a map, a guide, and a trail, they simply shouldn't get lost.

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A Few Examples

In my Complications example, moving quietly, I factored it as players or monsters being heard as 1-in-6 plus additions for acute perception, large groups, heavy armor, and large animals. In terms of this post, that would be ability score, context, tool, and assistance, respectively. A bit of a stretch to be sure, but it establishes the pattern.

Convince a person to grant you a favor: exceptional charisma, fluency in their language, a bribe,  a partner augmenting your argument, and familiarity with the target.

Stabilize a comrade from dying: uncommon perceptiveness as Wisdom (usually), medical training, medically supplies, a friend lending a hand, and attempting it in a clean distraction-free environment.

Tools may not be applicable in every circumstance, or may not be available in a medieval or early modern era. The rest of the factors should be achievable in most circumstances.

This idea draws from several places:

• The various Basic X-in-6 checks.
• LotFP X-in-6 skills.
• GLOG player-defined skills.
• My previous post about Complications that included a stealth mechanic.