Wire obstacle

During the time that the attackers are slowed by the wire obstacle (or possibly deliberately channelled into killing zones, or both) they are easy to target with machine gun and artillery fire.

Wire obstacles served to magnify the substantial advantage that the repeating rifle and rapid-firing artillery, along with machine guns, had given to the defending side in the new era of warfare.

Whenever there was time and opportunity to plan and emplace wire obstacles during World War I, it was standard practice to deploy designs that would channel and concentrate attacking troops, through avenues of approach, herding them like cattle into designated killing zones i.e. fixing multiple screw pickets of wire running diagonally, away from the protected zone.

Such gaps were designed to act like a funnel, luring attacking troops through the opening and straight into the concentrated direct and enfilade fire of different machine gun emplacements.

[citation needed] The effectiveness of any wire obstacle is greatly increased by planting anti-tank and blast antipersonnel mines in and around it.

If the use of lethal explosive devices is deemed to be unsuitable, it is easy to emplace tripflares in and around the wire obstacle in order to make night-time infiltration harder.