« Weapons and armour | Basic Roleplaying Rules Repository | Determinating Critical Successes »

## The effect of rolling doubles

Game System: Basic Roleplaying

Author: Bruce Mason

Added: 2006–09–16

### Summary

Whenever a character rolls double on percentile dice as part of a skills test then the result is significantly better or worse than usual. The usual effect of rolling a double is to gain a critical success or to suffer a fumble. This rule replaces the normal critical, special and/or fumble rules.

### Details

“Rolling a double” refers to any percentile roll with matching 10′s and units dice. The doubles are: 11, 22, 33, 44, 55, 66, 77, 88, 99, 00. In addition, the result “01″ counts as a double.

- Whenever you roll a double and fail a skill test you have “fumbled” and the result of the roll is “twice as bad as normal”.
- Whenever you roll a double and succeed at a skill test, you have “criticalled” and the result is “twice as good as normal”.
- The numbers 01 and 00 are “special doubles.” 00 is always the worst possible double result. “01″ is always the best possible double result.

#### Doubles and skills over 100.

If BRP or the BRP-based system you are using allows skills over 100% then some means of increasing your critical chance is needed. Various possibilities exist. E.g. if your skill% is over 100 then treat the excess over 100% as a critical threshold. E.g. if your skill is 125% and you roll 17 then your critical threshold is 25% so the roll of 17 is a critical.

### Effects on other rules

These rules replace any critical/special and fumble rules in action.

### Play notes

I have used this system in Call of Cthulhu and RQ3 and will use it in Mongoose RQ. I recommend that is used in conjunction with these other rules which I will add later:

- Skill results quality
- Opposed skill tests
- “Taking 100″

This is also a test for me at playing with this wiki.