Numenera, designed by Monte Cook, is the flagship setting for the Cypher System — a science-fantasy game whose whole resolution engine fits in a sentence. There is only ever one die to reach for, and much of the skill lies in what you do before you roll it.
The dice and the core mechanic
The Cypher System runs almost entirely on a single d20. Smaller dice appear only for damage and the occasional random table, but tests — combat, skills, saves, everything — use the d20 alone. Instead of adding modifiers to a character sheet full of numbers, the system leans on task difficulty, rated from 0 to 10.
The elegant trick is that a task’s difficulty sets its target number: difficulty × 3. A difficulty 1 task needs a 3 on the d20; a difficulty 5 task needs a 15; a fearsome difficulty 7 needs a 21, which a raw d20 cannot reach at all. That last point matters: some tasks are simply impossible until you lower the difficulty.
How a roll resolves
To attempt a task, the GM sets its difficulty (usually 1–7 for things characters actually try). You then reduce that difficulty using three tools, each step of reduction being called “easing” the task by one step — and each step lowers the target number by 3:
- Skills — being trained eases a task by one step; being specialised eases it by two.
- Assets — helpful tools or circumstances ease a task by up to two steps.
- Effort — you spend points from your stat Pools (Might, Speed or Intellect) to ease the task further, one step per level of Effort applied.
Only once the difficulty is settled do you roll. Meet or beat the final target number on the d20 and you succeed; the GM never rolls to oppose you, so you carry every roll in the game. The special faces add flavour: a natural 19 or 20 typically grants a minor or major effect (extra damage or a narrative bonus), while a natural 1 hands the GM a free GM Intrusion — a complication that twists the scene.
| d20 result | What it means |
|---|---|
| Natural 20 | Success plus a major effect (and, in combat, extra damage). |
| Natural 19 | Success plus a minor effect. |
| Meets the target | Straightforward success. |
| Below the target | Failure. |
| Natural 1 | The GM introduces a free Intrusion — something goes wrong. |
GM Intrusions are the system’s heartbeat. The GM can also spend to interrupt at other moments, offering you a complication; accept it and you gain XP (sharing one with another player), or pay a point of XP to refuse. This makes experience a currency of drama rather than a reward for slain monsters.
Effective strategy
Spend before you roll, not after. Because Effort, skills and assets lower difficulty rather than boosting a die you have already thrown, decide how badly you want a task before committing. A difficulty 4 fight (target 12) becomes a near-certainty once trained skill and a level of Effort drag it down to target 6.
Manage your Pools like ammunition. Might, Speed and Intellect double as both your health and your fuel for Effort. Burning Intellect to guarantee a social coup can leave you unable to shrug off an attack later. Pace your spending across a scene, not into the first roll.
Chase easing, not bonuses. Two steps of easing is worth a fixed −6 to the target — enormous on a d20. Positioning, preparation, the right tool and a helping ally routinely matter more than any single trait, so play to stack steps before difficult tasks.
Embrace the Intrusion. Refusing every complication drains your XP and starves the story. Accepting a well-timed Intrusion is often the smart, and profitable, move.
Because every test is one d20 against one number, you can roll a d20 in your browser and simply read it against the target you have worked out.
Beginner tips & common mistakes
- The target is difficulty × 3. Learn to convert instantly — difficulty 3 means a 9, difficulty 6 means an 18.
- You cannot roll above 20. Any task still at difficulty 7 or higher after easing is impossible until you bring it down; find another approach.
- Easing is subtraction from the target, never addition to the die. New players used to d20 modifiers often forget the maths runs the other way.
- Only the players roll. The GM sets difficulties and springs Intrusions; keep the dice in your hands.
- Don’t hoard Pool points to death. They are meant to be spent — a cautious character who never applies Effort simply fails more often.
No dice at the table? Dice Drop rolls real physics dice in your browser — pools, exploding dice and modifiers built in.
🎲 Roll dice freePrefer a d20 game with a bit more crunch on the sheet? Read our 13th Age dice & strategy guide.