The modern foil is descended from the training weapon for the small-sword, the common sidearm of the eighteenth-century gentleman. It is a light weapon, with a flexible, quadrangular blade, that scores only with the point. In modern sport fencing, which makes use of electrical scoring apparatus, one must hit the opponent with the tip of the blade, with a force of at least 4.90 Newtons (500 grams).

The valid target area at foil is limited, due to it having evolved from the time when fencing was practiced with limited safety equipment. Hits to the face were dangerous, so the head was removed from valid target. The target was then further reduced to only the trunk of the body, where the vitals are located. A touch which lands on a nonvalid target stops the fight, but no point is scored.