Combat Skill
All Combat Skill Offensive Schools (active & innate) require the corresponding gear to be equipped (i.e. to use a Blade skill you must have a sword in your hand). Note that all weapons and armor can be used by characters, increasing skills makes them more effective.
All Combat Skill Defensive Schools (active & innate) require the corresponding gear to be equipped (i.e. to use a Gambeson skill you must have Cloth Armor equipped). Note that all weapons and armor can be used by characters, increasing skills makes them more effective.