Sapping in the context of "Siege"

A siege (from Latin sedere 'to sit') is a military blockade of a city, or fortress, with the intent of conquering by attrition, or by well-prepared assault. Siege warfare (also called siegecraft or poliorcetics) is a form of constant, low-intensity conflict characterized by one party holding a strong, static, defensive position. The attacking party is said to be laying siege. Consequently, an opportunity for negotiation between combatants is common, as proximity and fluctuating advantage can encourage diplomacy.

A siege occurs when an attacker encounters a city or fortress that cannot be easily taken by a quick assault, and which refuses to surrender. Sieges involve surrounding the target to block provision of supplies and reinforcement or escape of troops (a tactic known as "investment"). This is typically coupled with attempts to reduce the fortifications by means of siege engines, artillery bombardment, or mining (also known as sapping), or the use of deception or treachery to bypass defenses.