The foil is a descendant of the light court sword formally used by nobility to train for duels. The foil has a flexible, rectangular blade, approximately 35 inches in length, and weighs less than one pound. Points are scored with the tip of the blade and must land within the valid target area, which is the torso from the shoulders to the groin in the front and to the waist in the back. It does not include the arms, neck, head and legs. This concept of on-target and off-target evolved from the theory of 18th-century fencing masters, who instructed their pupils to only attack the vital areas of the body. Of course, the head is also a vital area of the body, but attacks to the face were considered unsportsmanlike and therefore discouraged.
The foil fencer’s uniform includes a metallic vest (called a lamé), which covers the valid target area so that a valid touch will register on the scoring machine. The flexible nature of the foil blade permits the modern elite foil fencer to attack an opponent from seemingly impossible angles.