Dice mechanics
Percentile (d100) checks in Freeform / Custom
Roll under skill mechanics and difficulty bands.
Explanation
Percentile checks resolve by rolling d100 and succeeding at/under a target value. This mechanic is most directly associated with Call of Cthulhu-style play loops.
At the table (quick loop)
- Build your pool from the relevant traits.
- Roll and count successes according to the system’s thresholds.
- Apply consequences and record changes on the sheet.
Example: Treat every roll as a decision: success advances, failure changes the situation.
Examples
Example: skill target
If a system uses percentile checks, roll d100 and succeed at/under the target value.
Example: fail forward
If the clue matters, don't block progress on failure. Trade success for time, noise, or a new complication.
Common mistakes (smallest fix)
- Mistake: Forgetting difficulty bands. Fix: Use Regular/Hard/Extreme (or your table’s bands) to express stakes quickly.
- Mistake: Failure stops the investigation. Fix: Fail forward: you still get something, but pay a cost.