It was common for arrowslits to widen to a triangle at the bottom, called a fishtail, to allow defenders a clearer view of the base of the wall.[5] Immediately behind the slit there was a recess called an embrasure; this allowed a defender to get close to the slit without being too cramped.[6] The width of the slit dictated the field of fire, but the field of vision could be enhanced by the addition of horizontal openings; they allowed defenders to view the target before it entered range.[5]