The foil is the primary blade fenced in modern fencing. The foil originated as a training version of the small sword, a short, but incredibly sharp sword. The foil is also the weapon many fencers start of learning, partially because it teaches proper blade control. A little known fact about the foil is that its name comes from the term "foiled", which at the time meant "to dull the point". A proper foil is no more than 500 grams, less than 110 cm, and the guard has a maximum diameter of 12 cm.

    The foil follows the rules of "right of way", which is explained more in depth in the rules section, but inn short, "right of way" is not whether you hit your opponent first, but whether you hit him with priority. In foil you must hit using the point, and must hit the areas highlighted in red on the diagram. Foil also has one of the most controversial techniques in fencing, flicking. Flicking is an action where one of the fencers attacks very sharply and suddenly causing their blade to bend around their opponents' blade and landing a hit. For many years, this technique was considered acceptable, until the FIE(Federation International d'Escrime), the governing body of international fencing, decided that in a real duel, that flicking would not draw blood, and thus is not considered a hit. Even though flicking was made illegal, it was still quite easy to break the rules, as it is very difficult to notice such a fast action. To finally end the possibility of flicking, the FIE has mandated that all blades must be made stiffer, that way if someone attempts to flick, they would need to use much greater force, and thus it is easily detected.

    Many people often wonder why in foil you can only target the torso. The reason for that is because back when the foil was a training weapon for the smallsword, the best place you could hit some one is right in the heart, right in the middle of the chest. The foil itself has also changed greatly over the years. For one the blade has gotten slightly longer ever since the early twentieth century. Another major change is that the foible (the thinnest third of the blade, the tip) has gotten quite a bit longer, due to the fact that the tip is no longer required to be deadly-sharp.