Editing Siege (section)

====Defensive====
The universal method for defending against siege is the use of fortifications, principally walls and [[ditch (fortification)|ditches]], to supplement natural features. A sufficient supply of food and water was also important to defeat the simplest method of siege warfare: [[starvation]]. On occasion, the defenders would drive 'surplus' civilians out to reduce the demands on stored food and water.{{sfn|Hoskin|Howland|2006|p=105}}

During the [[Warring States period]] in China (481–221 BC), warfare lost its honorable, gentlemen's duty that was found in the previous era of the [[Spring and Autumn period]], and became more practical, competitive, cut-throat, and efficient for gaining victory.{{sfn|Ebrey|Walthall|Palais|2006|p=29}} The Chinese invention of the hand-held, trigger-mechanism [[crossbow]] during this period revolutionized warfare, giving greater emphasis to infantry and cavalry and less to traditional [[chariot]] warfare.

The philosophically [[pacifist]] [[Mohist]]s (followers of the philosopher [[Mozi]]) of the 5th century BC believed in aiding the defensive warfare of smaller Chinese states against the hostile offensive warfare of larger domineering states. The Mohists were renowned in the smaller states (and the enemies of the larger states) for the inventions of siege machinery to scale or destroy walls. These included traction trebuchet [[catapult]]s, {{convert|8|ft|m|adj=on}} high [[ballista]]s, a wheeled siege ramp with [[grappling hook]]s known as the Cloud Bridge (the protractible, folded ramp slinging forward by means of a counterweight with rope and pulley), and wheeled 'hook-carts' used to latch large iron hooks onto the tops of walls to pull them down.{{sfn|Turnbull|2002|p=40}}

[[File:Ireland-Cahir Castle.jpg|thumb|upright|[[Cahir Castle]] in Ireland was besieged and captured three times: [[Siege of Cahir Castle|in 1599]] by the [[Robert Devereux, 2nd Earl of Essex|Earl of Essex]], in 1647 by Lord Inchiquin, and in 1650 by [[Oliver Cromwell]].]]

When enemies attempted to dig tunnels under walls for mining or entry into the city, the defenders used large [[bellows]] (the type the Chinese commonly used in heating up a [[blast furnace]] for smelting [[cast iron]]) to pump smoke into the tunnels in order to suffocate the intruders.{{sfn|Ebrey|Walthall|Palais|2006|p=29}}

Advances in the prosecution of sieges in ancient and medieval times naturally encouraged the development of a variety of defensive countermeasures. In particular, [[medieval fortification]]s became progressively stronger—for example, the advent of the [[concentric castle]] from the period of the [[Crusades]]—and more dangerous to attackers—witness the increasing use of [[machicolation]]s and [[murder-hole]]s, as well the preparation of [[Early thermal weapons|hot or incendiary substances]].{{sfn|Sellman|1954|p=26}} [[Arrowslit]]s (also called arrow loops or loopholes), [[sally port]]s (airlock-like doors) for sallies and deep water wells were also integral means of resisting siege at this time. Particular attention would be paid to defending entrances, with gates protected by [[drawbridge]]s, [[portcullis]]es, and [[barbican]]s. [[Moat]]s and other water defenses, whether natural or augmented, were also vital to defenders.{{sfn|Sellman|1954|p=22}}

In the European [[Middle Ages]], virtually all large cities had city walls—[[Walls of Dubrovnik|Dubrovnik]] in [[Dalmatia]] is a well-preserved example—and more important cities had [[citadel]]s, [[fort]]s, or [[castle]]s. Great effort was expended to ensure a good water supply inside the city in case of siege. In some cases, long tunnels were constructed to carry water into the city. Complex systems of tunnels were used for storage and communications in medieval cities like [[Tábor]] in [[Bohemia]], similar to those used much later in [[Vietnam]] during the [[Vietnam War]].{{Citation needed|date=May 2009}}

Until the invention of [[gunpowder]]-based weapons (and the resulting higher-velocity projectiles), the balance of power and logistics definitely favored the defender. With the invention of gunpowder, cannon and [[mortar (weapon)|mortar]]s and [[howitzer]]s (in modern times), the traditional methods of defense became less effective against a determined siege.{{sfn|Sellman|1954|pp=44–45}}