The 3D6 System
When the outcome of an action is uncertain, the player rolls three six-sided dice. Each die that comes up lower than or equal to the relevant Ability score counts as a success.
Ficelle wants to chase a magpie by leaping from branch to branch. The Storyteller calls for a Strong roll. Ficelle has 3 in Strong and rolls 4, 4, and 6: no success. The magpie flies off with the prized saucepan.
Modifiers
An advantage (favorable circumstances, an ally's help, a relevant skill) lets you roll 4d6. When the advantage comes from a companion's help, the helper rolls no dice: the help is automatically granted, and only the Kitten being helped rolls his four dice. A disadvantage (injury, rough terrain, surprise) cuts the roll down to 2d6. If both apply at once, they cancel out. Several advantages or disadvantages at the same time do not stack: you never roll more than 4 dice nor fewer than 2.
A re-roll lets you replay a die of your choice that did not produce a success. A player can benefit from several re-rolls on the same roll. You get one when you use a relevant Purr-ecious item, when a Cattribute applies, or when the Storyteller judges the idea particularly clever.
Difficulty
| Level | Successes required | Examples |
|---|---|---|
| Easy | 1 | Climbing a tree, haggling for a small discount |
| Medium | 2 | Following a trail, balancing on a wet branch |
| Difficult | 3 | Escaping a bear, deciphering human writing |
| Legendary | 4 | Riding a bear, diving from a high cliff |
Success and failure
- As many successes as the difficulty or more: the action succeeds exactly as intended.
- Fewer successes than the difficulty: the player chooses. Either the Kitten fails with no further consequences, or he succeeds anyway but pays the cost through complications.
- No success: complete failure, the action is utterly botched.
Three identical dice always trigger something positive, whether the roll succeeds or not. The Storyteller improvises a small bonus or a favorable twist, even unrelated to the action.
Open actions
Some actions have no preset difficulty. The player rolls the appropriate ability and tries to score as many successes as possible. The Storyteller then assesses the success based on the circumstances.
Opposing actions
When two characters face off directly (a race, a contest, a negotiation), each rolls the appropriate ability. Whoever scores the most successes wins. In a tie, the Storyteller can call for a new roll or declare a draw.
Long tasks
For tasks that take time under pressure, the Storyteller sets:
- a total number of successes to accumulate (4 for a quick task, up to 16-20 for a long one)
- the time one roll takes (a minute, an hour, half a day…)
- optionally a time limit or mounting consequences
Several Kittens can work together by pooling their successes, or take turns if only one can act at a time.
Group actions
When all the Kittens carry out a common action, each rolls against the same difficulty. If the majority succeed, the whole group succeeds together.
The 3D6 System is based on an original idea by Croc and is used by other games: 
generic entry on Le Grog.