Sunday, January 1, 2017
OSR: A Task Resolution System based on Ability Scores
In my exploration of adjusting the niche of Thieves in OSR games here and here, I inadvertently stumbled upon the kernel of an idea for a Task Resolution Mechanic that could replace Thieves' Skills and any other task the player's might undertake.
The basic mechanic is that when a task occurs the DM decides upon a minimum Ability Score for the Task to automatically succeed, if it that automatic success is only available to a certain class or classes, and the Difficulty of the Task if an automatic success is not possible.
When an obstacle presents itself, the DM needs to choose the appropriate Ability Score and the minimum score necessary to overcome the obstacle automatically.
The Ability Score tiers are 13 (Challenging), 16 (Difficult), and 18 (Hard) mapping to the ranges of bonuses in Labyrinth Lord and other OSR games. I feel that anything between 9 and 12 shouldn't require much effort, personally.
Then the DM needs to set a Difficulty Class if no one has that minimum Ability Score. The DC's* are 75%, 50%, or 25%. No Ability Score modifier is added to this roll. At this point Class Features like Thief Skills or appropriate backgrounds give the character a +5 to the roll. A 1 creates either a failure or an additional complication. The DM is free to decide a Task Check is impossible for a character, but may at their option, require a Natural 20 on the roll to succeed.
The DM also has the option of ruling that the necessary equipment is required for any situation.
So let's say a party of adventurers encounter a locked chest. The DM has decided that a character with an Intelligence Score of 16+ can Find and Remove the trap on the chest; if no character has an Int that high, the task requires a d20 roll of 16+ to succeed. However if a Thief is in the party, their Find and Remove Trap class feature gives them a +5 to the roll.
Next the party is trying to open the chest, which requires a Dexterity Score of 13+ to automatically succeed; if no character has a Dex that high, the task has a DC of 11+ to succeed. If there is a Thief in the party, their Pick Locks class feature gives them a +5 to the roll.
This can easily be extended to other challenges, for instance a door requires a Strength Score of 18+ or a DC of 16+, and the DM allows a Fighter to have a +5 to the roll. Or the party finds a strange idol that requires an Intelligence of 16+ or a DC of 11+, and the DM allows a Cleric to have a +5 on the roll.
*I stole these DCs from 13th Age.