12:20 (“twelve-twenty’) is an extremely lightweight narrative system intended for use as a side activity alongside some other tabletop role-playing game. It

When a character in a 12:20 scene wishes to take an action that has a chance of failure, they must make a 12:20 check.

The character receives two d12s. These are their attempt dice. They also receive a d20. This is the difficulty die. There are only ever two attempt dice and one difficulty die in play for any given check. Additionally, beneficial circumstances may grant the character bonus dice, and detrimental circumstances may confer penalty dice. The entire dice pool is rolled together, and the total of the attempt and bonus dice are compared against the total of the difficulty and penalty dice. If the total of the attempt and bonus dice is greater, the check results in a success. Otherwise, the check results in a failure.

Bonus dice are granted by circumstances that improve the character's ability to succeed at a check. For each positive circumstance, add one d6 to the check’s bonus dice.

Penalty dice are conferred by circumstances that significantly reduce a character’s ability to succeed at a check. For each negative circumstance, add one d10 to the check’s penalty dice. There may only be six penalty dice for any given check.

If a character has proficiency in an applicable skill, they may apply one skill towards their 12:20 check, adding as many bonus dice as they have proficiency levels, up to 4. If skill proficiencies are not leveled, but are derived from some other modifier, they may add a number of bonus dice equal to their modifier. If a 12:20 check is being made against a character that is given the opportunity to defend, that character may apply skill proficiencies to add penalty dice to the check. Finally, an ally may apply one of their own skill proficiencies to assist or hinder a 12:20 check, adding a single bonus or penalty die, respectively.

Caveats are narrative effects that influence the result of a check. If every two attempt dice that roll higher than the difficulty die, add an advantage. For every two attempt dice that roll lower than the difficulty die, add a setback. One advantage and one setback cancel each other out.

If a character faces more than two penalty dice, they may opt to Take a Risk and remove two penalty dice, downgrading their attempt dice to two d8s. This increases their chances of success at the cost of dramatically increasing the probability of a setback. If any penalty dice remain, they may opt to Take a Greater Risk and remove two more penalty dice, downgrading their attempt dice to two d4s.

This work is inspired by Pathfinder, Second Edition and Genesys.

© 2022 Ethan Wu. This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 license.