The Fairbairn-Sykes Fighting Knife is a double-edged fighting knife

Fighting knife

A fighting knife is a knife with a blade designed to inflict a lethal injury in a physical confrontation between two or more individuals at very short range...

 resembling a dagger

Dagger

A dagger is a fighting knife with a sharp point designed or capable of being used as a thrusting or stabbing weapon. The design dates to human prehistory, and daggers have been used throughout human experience to the modern day in close combat confrontations...

 or poignard

Poignard

Poignard, or poniard, , refers to a long, lightweight thrusting knife with a continuously tapering, acutely pointed blade and crossguard, historically worn by the upper class, noblemen, or the knighthood...

 with a foil

Foil (fencing)

A foil is a type of weapon used in fencing. It is the most common weapon in terms of usage in competition, and is usually the choice for elementary classes for fencing in general.- Components:...

 grip developed by William Ewart Fairbairn

William E. Fairbairn

William Ewart Fairbairn was a British soldier, police officer and exponent of hand-to-hand combat method, the close combat, for the Shanghai Police between the world wars, and allied special forces in World War II. He developed his own fighting system known as Defendu, as well as other weapons...

 and Eric Anthony Sykes

Eric A. Sykes

Eric Anthony Sykes , born Eric Anthony Schwabe in Barton on Irwell, Manchester, England. He is most famous for his work with William E. Fairbairn in the development of the eponymous Fairbairn-Sykes Fighting Knife and modern British Close Quarters Battle martial arts during World War II...

 in Shanghai

Shanghai

Shanghai is the largest city by population in China and the largest city proper in the world. It is one of the four province-level municipalities in the People's Republic of China, with a total population of over 23 million as of 2010...

 based on concepts which the two men initiated before World War II while serving on the Shanghai Municipal Police in China.

The F-S fighting knife was made famous during WWII when issued to British Commandos

British Commandos

The British Commandos were formed during the Second World War in June 1940, following a request from the British Prime Minister, Winston Churchill, for a force that could carry out raids against German-occupied Europe...

, including the SAS

Special Air Service

Special Air Service or SAS is a corps of the British Army constituted on 31 May 1950. They are part of the United Kingdom Special Forces and have served as a model for the special forces of many other countries all over the world...

. With its acutely tapered, sharply-pointed blade, the F-S Fighting knife is frequently described as a stiletto

Stiletto

A stiletto is a knife or dagger with a long slender blade and needle-like point, intended primarily as a stabbing weapon. The stiletto blade's narrow cross-section and acuminated tip reduces friction upon entry, allowing the blade to penetrate deeply...

, a weapon optimized for thrusting, although the F-S knife is capable of being used to inflict slash cuts upon an opponent when its cutting edges are sharpened according to specification.