3d6 Risus is a tool to help even out the disparities in actions and conflicts. Its DNA goes back to the dice mechanics in GURPS and the “roll under” games of the 1980s.
If the outcome of a character’s action is in doubt, the player rolls 3d6. If the total is 10+(Cliché-Difficulty) or less, the effort succeeds; on a higher roll there is some sort of failure or complication. The Difficulty is either the opposing Cliché in a conflict or the Target Number divided by 5 for other actions.
Say that Thissa Raintraveler, a sage wandering the land to create a map of clouds (3), wants to climb a very steep cliff (4) to get a better view of the sky. Her player would have to roll 9 or under (10+3-4) for her to safely make it to the top of the cliff.
The GM may want to treat any roll of 15 or higher as an automatic failure and a roll of 6 or less as an automatic success.