What does X mean in an action's cost, and when do I choose it?

Question

Accepted Answer

Choose X from 1 to 6 before rolling, then treat it as the printed cost: you roll that many challenge dice unless skill tokens reduce it, and the result scales with X. The result is read only after the dice steps. Choosing 1 is allowed and means one die.

Vantage

What does X mean in an action's cost, and when do I choose it?

Vantage

What does X mean in an action's cost, and when do I choose it?