Stress die
Rolling a stress die refers to a method of the Ars Magica game mechanics to determine the outcome of an action or event under stressful circumstances. A stress die carries with it the possibility of spectacular success or catastrophic failure.
First, you roll a single ten-sided die, which is typically numbered 0 through 9. A zero is special: there is a chance the character will Botch, and the player must roll botch dice to see whether that happens. Even if no botch occurs, the roll is treated as zero.
A 1, on the other hand, allows the player to roll again, doubling the result of the next roll. Additional 1's multiply the next result by four, eight, sixteen, and so forth, until a number other than 1 is rolled. All other numbers (2-9) count as their actual values. On the second and subsequent roll, a zero stands for a value of 10.
- Example: You roll 3. The result is 3.
- Example: You roll 0. The result is 0, and you must roll a certain number of botch dice determined by the Storyguide to see if you botch.
- Example: You roll 1, roll 0. The result is 20, because zero counts as 10 on the second and subsequent rolls.
Unlike a Simple Die that is used in relaxed situations, a Stress Die is used to reflect stressful circumstances. Combat and most spell casting are both examples for the use of a Stress Die. Due to the open-ended multiplication from rolling consecutive 1's, a stress die can (rarely) yield spectacular results.
Criticism
The fan community has raised two issues regarding the stress die. First, the doubling with each new "1" leads to exponentially large results, which can be jarring and inappropriate for some groups. Such exponential success will probably work well if your game is full of heroic-action, but will feel inappropriate and weird if your game is gritty and "realistic".
A second consideration is that the roll feel weird, as '1' or '0' on the dice is sometimes good and sometimes bad, and can be disappointing in that once you finally do get a '1' on your stress roll you follow-up by rolling a '2' for a final dismayingly-low result of 4.
Groups that find these issues especially distressing may choose to change how the stress dice is rolled through a house rule. Most groups don't really notice any problem, or if they do it's so minor that they don't bother.
References
See Also
Legacy Page
The history of this page before August 6, 2010 is archived at Legacy:stress_die