Area denial weapon

In medieval warfare, sturdy stakes were stuck into the ground at the bottom of long lines of ditches, positioned with a sharp end pointing up diagonally, in order to prevent cavalry charges in a given area.

The correct layout of these extensive lines of ditches and the control of stake size, form and placement were part of the craft of war.

An alternative cavalry deterrent, allowing quicker dispersal and providing the advantage of being hidden more easily, was the deployment of, for example, small balls with spikes, used during most of antiquity.

Some South American urban guerrillas such as the Tupamaros and Montoneros, who called them "miguelitos," have used caltrops to avoid pursuit after ambushes.

Booby traps or improvised explosive devices in sufficient concentration also qualify as area denial weapons, though they are much easier to clear and usually pose less long-term danger.

Various CBRNE (chemical, biological, radiological, nuclear, and explosive) weapons can be used for area denial, as long as the agent is long-lasting.

Such systems are usually envisioned as a combination of either explosives, pre-targeted artillery shelling or smartguns with remote sensing equipment (sound, vibration, sight/thermal).

[4] As area denial weapons do not discriminate between friend, foe, or civilian, they make the affected zone hazardous for all trying to enter.

Concepts for area denial weapons which do discriminate (by active sensing) have often been proposed, but have not yet reached a stage of general usefulness, due to their high complexity (and cost) and the risk of misidentification.