In most countries special forces (SF) is a generic term for highly-trained military teams/units that conduct specialized operations such as reconnaissance, unconventional warfare, and counter-terrorism actions. (In the United States, the term Special Operations Forces (SOF) is used instead of special forces to refer to the aforementioned units because Special Forces refers to a specific unit, the United States Army Special Forces aka "Green Berets".)

Some special forces operations, such as counter-terrorism actions, may be carried out domestically under certain circumstances. Special forces units are typically composed of relatively small groups of highly-trained personnel equipped with specialist equipment and armament, operating under principles of self-sufficiency, stealth, speed, and close teamwork, often transported by helicopter, small boats or submarines, parachuting from aircraft, or stealthy infiltration by land. Special forces are sometimes considered a force multiplier, as when they train indigenous forces to fight guerrilla warfare.

History of special forces

Special forces have played an important role throughout the history of warfare when the aim has been to achieve disruption by "hit and run" and sabotage, rather than more traditional face-to-face combat. Other significant roles lay in reconnaissance, providing essential intelligence from close to or among the enemy, and increasingly in combating terrorists, their infrastructure and activities.

In antiquity, Hamilcar Barca in Sicily had specialized troops trained to launch several offensives per day. Later, during the Crusade wars, small, highly trained units of Knights Templar attacked individual Muslim units attempting to forage or seize booty. Muslim armies had several naval special operations units, including one which used camouflaged ships to gather intelligence and launch raids, and another which consisted of soldiers who could pass for Crusaders who would use ruses to board enemy ships and then capture and destroy them. In ancient China and Feudal Japan, specially trained martial artists, called Ninja, were employed to fight guerilla warfare, unconventional warfare, as well as engage in espionage and assassinations.

During the Napoleonic wars, rifle and sapper units existed who were not committed to the formal lines that made up most battles of the day. They instead held more specialised roles in reconnaissance and skirmishing.

World War I

During World War I Colonel Bassi of the Italian Army formed 27 battalion-sized "Reparti d'assalto" (Assault Units) called Arditi. They were assigned the tactical role of shock troops, breaching enemy defenses in order to prepare the way for a broad infantry advance. The Reparti d'assalto were successful in bringing a degree of movement to what had previously been a war of entrenched positions. The Arditi were not considered infantry troops, but were seen and organized as a separate combat arm and therefore received extended tactical training, the best and newest weapons and a distinct new uniform. Thus they are some of the modern world's first special forces. On the German side, the success of the Spring Offensive reflected on their successful employment of specially trained stormtrooper or Sturmtruppen units, whose unconventional infiltration tactics made them de facto special forces.