Rule of ...

There are various Rules of ... in GURPS which are so short that it made sense to combine them on one page.

Rule of 10s

The rule of 10s of Knowing Your Own Strength, creatures under ST 7 add 10 to ST to determine damage but divide result by 10.

When applying modifiers, you occasionally need to know the r=ange, area of effect, or duration of an advantage for which one or more of these quantities is not specified – for instance, when applying an enhancement that gives a range to an ability that normally has none.

Assume that range is 100 yards, area is a circle 2 yards in radius (and 12’ high, should volume matter), and duration is 10 seconds

This might be useful for things like:

• Affects Others
• Aura
• Leech

See Also

• Fractional Damage

Rule of 14

A Fright Check fails on any roll of 14+, regardless of modified Will

Rule of 15

Renamed Brave in later books this perk from Power-Ups 2: Perks changes Fright Check's failure to 15+.

Rule of 16

"If a supernatural attack (magic spell, psi ability, etc.) offers a resistance roll and the subject is living or sapient, the attacker’s effective skill cannot exceed the higher of 16 and the defender’s actual resistance. If it does, reduce it to that level.

Example: A wizard has an effective skill of 18 with his Mind-Reading spell. If he tries to read the mind of someone with a Will of 16 or less, he rolls against 16. If his subject has a Will of 17, he rolls against 17. And if his target has a Will of 18 or higher, he rolls against 18."

Note: Enforce The Rule of 16 after both sides have added all modifiers.

Rule of 20

Rule of 20: any skill (or attribute) above 20 is treated as 20 for the purposes of default.

"Treat any core skill greater than 20 as 20 for the purpose of default calculation, so that college skills never have a default greater than 14." In Path/Book magic it is Paths that never have a default greater than 14.

See Also

• No Default