Call of Cthulhu d100
The Resistance Table
Sometimes you’ll have to make a check against something that there isn’t an appropriate skill for. In this case, the rolls are made using your character’s attributes. Based on the particular situation, an attribute will be chosen to be used. If your character is in an arm-wrestling contest, for example, you will need to make a roll using their STR attribute, since there isn’t and Arm-Wrestling skill. These checks can be handled one of two ways, depending on which attribute is being used. For checks against the Idea, KNW, Luck, or SAN attributes, you do it the same way as a regular skill check. Roll a D100, and if the roll is equal to or less than the corresponding attribute, you succeed at the check. Since your other attributes are probably much lower than those four however, they are handled a little differently, using the resistance table:
You need two numbers to use the resistance table, a passive characteristic and an active one. The active characteristic is the attribute your character is using for the challenge, while the passive characteristic is the one he/she is competing against. Using the arm wrestling example from before, the active characteristic would be your character’s STR and the passive characteristic would be the other arm wrestler’s STR. If there is no clear number to be used as the passive characteristic, then the game’s host will choose a value to be used that fits the difficulty level of the challenge.
Once you have both an active and passive characteristic, use the resistance table to look up the corresponding difficulty. For example, if your character has a STR of 13 and the other arm wrestler’s strength is 18, the difficulty of the challenge is 25. Once you’ve found the difficulty of the challenge, the rest is simple: do a skill check using the difficulty number. If you roll equal to or less than the difficulty number, then you clear the check and succeed at whatever task your character was attempting.