Trench warfare is a type of warfare characterized by the establishment of defensive emplacements lodged in trenches, with both sides occupying trenches for the purpose of holding a defensive position. This type of warfare becomes a very slow war of attrition, with both sides picking away at each other in an attempt to gain an advantage. It is infamously brutal and horrific, and is perhaps most closely associated with the First World War, in which the infamous trenches in France were occupied from 1914 to 1918.
Several factors coalesced to create the phenomenon of trench warfare. The first was tremendous advances in ballistics which made traditional frontal assaults logistically difficult. The increased accuracy of weapons and the increased lethality of artillery turned a traditional charge into suicide, making more defensive approaches necessary. The development of better supply tactics also contributed, by making it possible to hold an area for a prolonged period of time with the assistance of supplies from trains and trucks which approached the trenches from the rear.
In trench warfare, both sides establish fortifications including sandbags, walls, and barbed wire fences while digging trenches. The trenches are designed to provide cover from artillery. Once ensconced in a trench, an occupying force is extremely difficult to dislodge, because even though casualties may be suffered, reinforcements can be brought up from the rear. The area between trenches occupied by rival forces, known as “no man's land,” can be used as a staging area for charges and sorties, although soldiers in no man's land are very vulnerable to attacks from the other side.
In the trenches, life is nothing short of horrific. During the First World War, dead bodies were allowed to lie in shallow graves in the floors and walls of the trenches, contributing a strong odor to the already intense stench of unwashed bodies and overflowing latrines. Supplies of food, while available, were not usually of very high quality, and soldiers were typically covered in lice and prone to serious infections which could kill them before they even fired a shot in anger. Conditions in the trenches were also extremely stressful, with soldiers subjected to artillery barrages from the other side, and sniper's bullets if they dared to poke their heads over the fortifications. This contributed to the development of psychological problems among soldiers stationed in the trenches. Many militaries responded to psychological issues with a firing squad, ordering soldiers executed for acts of perceived cowardice or desertion.
Military actions in the trenches could be accomplished in a number of ways. German forces in the First World War notoriously used gas to kill or incapacitate rival soldiers before going “over the top” of their emplacements so that they could storm and occupy trenches held by rival forces. Artillery was also used in an attempt to subdue enemy forces before launching an attack, and both sides used snipers and small commando teams to maintain a constant state of tension and fear. For much of the time, rival forces ended up in a standoff, with both successfully holding their trenches but no movement occurring in either direction.
When soldiers successfully occupied enemy trenches, they might find themselves within shouting distance of enemy forces, who typically gave up ground reluctantly, retreating just far enough for safety. New occupiers also inherited all of the creature comforts which might have been left behind, ranging from stockpiles of food to gramophones with stocks of records.
The brutality of trench warfare has been immortalized in a number of films and books, including books by soldiers who actually endured it. All Quiet in the Western Front and Life in the Tomb are two examples of novels about the First World War written by veterans who survived trench warfare.