The Anarchy of King Stephen
Spellcraft is a very important skill, representing the skill that a spellcaster has with magic. It is both a passive skill, like Dodge, and an active skill.
Normally, Spellcraft is a passive skill: a caster’s ranks in Spellcraft take the place of the “caster level” term used in d20 supplements. This does mean that a caster will initially be considerably more powerful than his D&D counterparts; however, as his rank in Spellcraft increases only at a rate of one per two levels (the same as all other skills), high-level casters are no more powerful than D&D mages.
Spellcraft sees active use whenever a spell requires an attack roll. Typically, a spell’s attack roll is DEX + Spellcraft.
Identifying a spell as it is cast, or other “knowledge” uses of Spellcraft, are handled by Knowledge (arcana) in the Kingdom of Wessex setting.