Weapons can be enchanted with either Enhancement Bonuses(max: +5) or Magical Effects(max:+9). Each weapon has 10 "slots" to use. For a weapon to be enchanted it must be a masterwork weapon, to enchant it with a Magical Effect the weapon must have an Enhancement Bonus of +1. After a masterwork weapon has it's first +1 enchantment you can start adding Magical Effects or additional Enhancement Bonuses.