Success Rolls
Whenever a character attempts to perform an action (e.g., use a skill), roll three dice to determine the outcome. This is called a success roll. The task in question succeeds if the total rolled on the dice is less than or equal to the number that governs the action – most often a skill or an attribute. Otherwise, it fails.
- Example: If you attempt to pick a lock with a Lockpicking skill of 9, you must roll 9 or less on 3d to succeed. On a roll of 10 or more, you fail.
- Regardless of the score you are rolling against, a roll of 3 or 4 is always a success, while a roll of 17 or 18 is always a failure.
In general, the player makes the die rolls for his character’s actions. However, the GM may always choose to roll the dice in secret – see When the GM Rolls, below.
When to Roll
To avoid bogging down the game in endless die rolls, the GM should only require a success roll if there is a chance of meaningful failure or gainful success. In particular, the GM should require success rolls when...
- A PC's health, wealth, friends, reputation, or equipment are at risk. This includes chases, combat (even if the target is stationary and at point-blank range!), espionage, thievery, and similar "adventuring" activities.
- A PC stands to gain allies, information, new abilities, social standing, or wealth.
The GM should not require rolls for...
- Utterly trivial tasks, such as crossing the street, driving into town, feeding the dog, finding the corner store, or turning on the computer.
- Daily work at a mundane, nonadventuring job. (To evaluate job performance, make monthly "job rolls"; see Jobs)
When the GM Rolls
There are two sets of circumstances under which the GM should roll for a PC and not let the player see the results:
1. When the character wouldn't know for sure whether he had succeeded. This is true of all rolls to gain information, whether through skills such as Detect Lies, Interrogation, Meteorology, and Search, advantages like Intuition and Oracle, or supernatural divinatory abilities. In this situation, the player declares that he is using his ability and the GM rolls in secret. On a success, the GM gives the player true information – the lower the roll, the better the information. On a failure, the GM either gives no information at all or lies (the higher the roll, the more severe the lie), as appropriate.
2. When the player shouldn't know what's going on. This includes most Sense rolls, rolls to use Danger Sense, etc. Suppose the party is walking along a jungle trail. A jaguar is on a limb ahead. The GM should not say, "There’s a jaguar ahead of you. Roll to see if you notice it." Neither should he say, "Everybody make a Vision roll. Does anybody have Danger Sense?" Either of these approaches gives too much away. Instead, the GM should roll for each character in secret. If anyone succeeds, the GM can say, "You notice a jaguar on a branch 20 yards ahead!" If nobody succeeds ... they're in for a surprise.
Modifiers
The rules often specify modifiers for certain success rolls. These bonuses and penalties affect the number you are rolling against – your "target number" – and not the total rolled on the dice. Bonuses always improve your odds, while penalties always reduce them.
For instance, the Lockpicking skill description states, "-5 if working by touch (e.g., in total darkness)." This means that if you are working in the dark, you must subtract 5 from your Lockpicking skill for that attempt. If your Lockpicking skill is 9, you roll against 9 minus 5, or 4, in the dark.
A specific scenario might provide modifiers to allow for the relative ease or difficulty of a particular situation. For instance, an adventure might state that a lock is +10 to open due to the fact that it is primitive and clumsy. If your Lockpicking skill were 9, you would roll against 9 + 10, or 19. Since the highest roll possible on 3d is 18, it would seem that success is assured. This is almost true, but not quite – see Critical Failure.
Modifiers are cumulative unless stated otherwise. For instance, if you tried to open that primitive lock in the dark, both modifiers would apply, and you would roll against 9 - 5 + 10, or 14. See Culture, Language, Tech-Level Modifiers, Familiarity, Equipment Modifiers, and Task Difficulty for discussions of common modifiers.
Base Skill vs. Effective Skill
Your base skill is your actual level in a skill, as recorded on your character sheet. Your effective skill for a particular task is your base skill plus or minus any modifiers for that task. In the Lockpicking examples above, base skill is 9 in all cases, while effective skill is 4, 19, and 14 in three different situations.
The terms "base skill" and "effective skill" apply to all success rolls, not just to skill rolls. When you make an attribute roll, defense roll, self-control roll, etc., your base skill is your unmodified score, while your effective skill is your final, modified target number.
You may not attempt a success roll if your effective skill is less than 3, unless you are attempting a defense roll.
Default Rolls
When a task calls for a skill roll, you must have some ability with the required skill in order to attempt the task. Ideally, you want points in that skill ... but an untrained person can take a stab at most tasks. For instance, anyone can swing a sword – although only a trained warrior is likely to have much success at it.
A skill that anyone can attempt without study is said to “default” to an attribute or another skill. This means you can attempt the desired action by rolling against one of your attributes or other skills at a penal- ty. This “default roll” is just an ordinary success roll.
- Example: Lockpicking skill defaults to "IQ-5"; that is, anyone can open a lock, without training, by making a success roll against 5 less than his IQ. If your IQ is 10, you can open an ordinary lock on a roll of 5 or less on 3d. The smarter you are, the better your chances – but training is always preferable!
The description of each skill shows what skills or attributes it defaults to, and at what penalties. If a skill offers multiple defaults, always choose the best one.
- Example: Interrogation defaults to "IQ-5, Intimidation-3, or Psychology-4." If you're not a trained interrogator, you can still get answers out of a prisoner by outthinking him (IQ-5), frightening him (Intimidation-3), or playing "mind games" with him (Psychology-4). If you had IQ 12, Intimidation at 14, and Psychology at 13, your defaults would be 7, 11, and 9, respectively. Roll against 11, the highest of the three.
The Rule of 20
If you have a basic attribute over 20, treat it as 20 for default purposes. For instance, if you have IQ 25, your default Lockpicking skill (IQ-5) is 15 – not 20. No such limit applies to defaults to other skills.
"No Default"
Some actions are impossible without training. Skills like Alchemy, Karate, and magic spells have no default. If you lack the proper training, you can't attempt these things at all.