Casting of Bones
Description: By throwing dice carved from the knuckle-bones of executed criminals, a vampire may attempt to divineand positively influence his fate.
System: The player rolls one die. If the result is six (6) or greater, the next roll for the character is made at minus one (-1) difficulty. If the result is 5 or less, add one to the difficulty for the character's next roll. Every time this ritual is cast in a given night, reduce the resulting number of the die by one. No matter what, a roll of ten (10) always yields good luck.
Reference: Players Guide to the High Clans - Mortis Rituals - Page 197.