Description: Each Caster can only try to cast each of its Learned Spells once per Magic Phase, and it may try to cast a Bound Spell once for each time it has it. If multiple Casters knows the same Spell, all of them may try to cast their instance(s) of the Spell.
When making an attempt to cast a Learned Spell where a version of the same spell (either Bound or Learned) has already been attempted (successfully or not), then the Casting Roll reduced by 3. This is reduced by another 3 for each additional attempt in the same phase. For example, if 2 instances of a spell have been attempted, the Casting Roll is reduced by 6.
If instead attempting to cast a Bound Spell, the Casting Roll is only reduced by 1, instead of by 3, for each time a version of the same spell has already been tried.
Remember that Replicable Spells ignore this modifier but still count as a casting.