Trench warfare

Template:History of war Trench warfare is a form of war in which both opposing armies have static lines of fortifications dug into the ground, facing each other. Trench warfare arose when there was a revolution in firepower without similar advances in mobility and communications. Periods of trench warfare occurred during the American Civil War (1860s) and the Russo-Japanese War of 1904–1905, and reached peak brutality and bloodshed on the Western Front in the First World War.



Fortification is almost as old as warfare itself; however, because of the relatively small size of the armies and the lack of range of the weapons, it was traditionally not possible to defend more than a short defensive line or an isolated strongpoint. The very long fortifications of the ancient world, such as the Great Wall of China or Hadrian's Wall, were exceptions to the general rule and were in any case not designed to completely prevent entry of enemy troops, but simply to make it difficult for the invader to mount a penetration in strength. The Great Wall of China, for example, was not intended to keep raiders out, but merely to prevent them from bringing their horses.

Although both the art of fortification and the art of weaponry advanced a great deal in the second half of the second millennium, the advent of the longbow, the muzzle-loading musket, and even of artillery did not substantially change the traditional rule that a fortification required a large body of troops to defend it. Small numbers of troops simply could not maintain a volume of fire sufficient to repel a determined attack.

Siege warfare

Most of the techniques used in trench warfare had existed for years in siege warfare. It was the implementation of these techniques between two armies in the field which was new.

Julius Caesar in his Gallic Wars describes how at the Battle of Alesia the Roman legions created two huge fortified walls around the city. The inner circumvallation, 10 miles, held in Vercingetorix's forces, while the contravallation kept relief from reaching them. The Romans held the ground in between the two walls. The besieged Gauls, facing starvation, eventually surrendered with their relief force standing by helpless.

Once siege guns were developed the techniques involved in assaulting a town or a fortress became well known and ritualised. The attacking army would surround a town. Then the town would be asked to surrender. If they did not comply the besieging army would invest (surround) the town with temporary fortifications to stop sallies ( from the stronghold or relief getting in. The attackers would then build a length of trenches parallel to the defences and just out of range of the defending artillery. They would then dig a trench towards the town in a zigzag pattern so that it could not be enfiladed by defending fire. Once within artillery range another parallel trench would be dug with gun emplacements. If necessary using the first artillery fire for cover, this process would be repeated until guns were close enough to be laid accurately to make a breach in the fortifications. So that the forlorn hope ( and support troops could get close enough to exploit the breach, more zigzag trenches could be dug even closer to the walls with more parallel trenches to protect and conceal the attacking troops. After each step in the process the besiegers would ask the besieged to surrender. If after the forlorn hope stormed the breach successfully the defenders could expect no mercy.

Maori Pas

The Maori of New Zealand had built stockades called Pa on hills and small peninsulas for centuries before European contact. These resembled the small Iron age forts which dot the British and Irish landscapes. When the Maori encountered the British they developed the Pa into a very effective defensive system of trenches, rifle pits and dugouts, and which pre-dated similar developments in America and Europe. In the Maori Wars for a long time the modern Pa effectively neutralized the overwhelming disparity in numbers and armaments. At Ohaeawai Pa in 1845, at Rangiriri in 1864, and again at Gate Pa in 1864 the British and Colonial Forces discovered that a frontal attack on a defended Pa was both ineffective and extremely costly.

At Gate Pa during the Tauranga Campaign, in 1864 the Maori withstood a day long bombardment in their bomb shelters. One authority calculated that Gate Pa absorbed in one day a greater weight of explosives per square metre than did the German trenches in the week-long bombardment leading up to the Battle of the Somme. Having destroyed the pallisade, the British troops entered the Pa whereupon the Maori fired on them from hidden trenches, killing 38 and injuring many more in the most costly battle for the Pakeha of the Maori Wars. The Maori then abandoned Gate Pa. The Maori developed their ideas on Pa design over a very short period, from the stone age to the level of World War One in little over 30 years.


The first development which was critical for trench warfare was the introduction of mass-conscripted armies during the French Revolution and the Napoleonic Wars. Prior to this, armies still consisted of small numbers of troops which were unable to defend a large territory for very long—battles were either brief or degenerated into siege warfare. Large armies made it much more difficult for one army to outflank another, but it was still possible with cavalry and infantry charges for one army to break another by a direct assault. An example of an early fortified military line which stretched for many miles was the Lines of Torres Vedras (1810), which was built by the Portuguese under the direction of Royal Engineers of the British Army during the Peninsular war.

What made this tactic increasingly suicidal was the development of improved firearm technology in the mid-19th century. When the American Civil War opened in 1861, it was fought with the same tactics that had been used in the era of Napoleon and indeed for several centuries. By the time the war drew to a bloody close in 1865, it had become a preview of the First World War, complete with trenches, machine guns, field fortifications, and massive casualties. The Battle of Petersburg near the end of the war with its trenches and static formations, contrasts sharply with the early battles such as the First Battle of Bull Run where maneuver was still possible, and famous charges such as Pickett's Charge at the Battle of Gettysburg, revealed the military futility of a direct assault on an opposing line.

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A Cheshire Regiment sentry in a trench near La Boisselle during the Battle of the Somme, July 1916

Two main factors were responsible for the change. First, the new breech-loading firearms—which were curiously ignored by both sides until mid-way through the conflict—made it possible for a small number of troops to maintain a heavy volume of fire. A handful of defenders sheltering in a trench or behind an improvised obstacle could hold off a large body of attackers indefinitely. Second came the machine gun, which multiplied the power of the defender still further and yet did little for an attacker (provided that only the defenders could take cover).

Two other factors played a part. The first was the development of barbed wire, which in itself did little harm to anyone but—crucially—could slow the progress of an attacking force, and thus allow emplaced machinegunners and riflemen time to inflict unacceptable losses.

The second came after the end of the American Civil War, with the invention of modern high-velocity breech-loading artillery. Artillery in one form or another had been a part of warfare since classical times, and from the rise of gunpowder until the development of trench warfare in the 1860s had been a major killing force. With the development of modern artillery by Krupp, however, artillery regained much of its former killing power (as was graphically demonstrated in the Franco-Prussian War of 1870 to 1871). Artillery would reach its peak during the two World Wars, where it was the most decisive weapon on the battlefield.


Although firearms technology and the conscript army dramatically changed the nature of warfare, most armies were completely unaware of the implications of these changes and unprepared for their consequences. At the start of World War I, most armies prepared for a brief war whose strategy and tactics would have been familiar to Napoleon.

However, as war broke out, German and Allied (mostly French and British) forces soon learned that with modern weapons even a shallow scrape in the soil could be defended by a handful of infantry. To attack frontally was to court crippling losses, so an outflanking operation was essential. After the Battle of the Aisne in September, 1914, an extended series of attempted outflankings, and matching extensions to the fortified defensive lines, soon saw the celebrated "race to the sea"—the German and Allied armies dug what was essentially a single pair of trenches from the Swiss border in the south to the North Sea coast of Belgium. Trench warfare prevailed on the Western Front from September 16, 1914, until the Germans launched their "Spring Offensive", Operation Michael, on March 21, 1918.

On the Western Front, the small, improvised trenches of the first few months rapidly grew deeper and more complex, gradually becoming vast areas of interlocking defensive works. The space between the opposing trenches was referred to as "no man's land" and varied in distance depending on the battlefield. On the Western Front it was typically between 100 and 300 yards, though only 30 yards on Vimy Ridge. After the German withdrawal to the Hindenburg line in March 1917 it stretched to over a kilometre in places. At the infamous "Quinn's Post" in the cramped confines of the Anzac battlefield at Gallipoli, the opposing trenches were only 15 metres apart and a bombing war was waged there incessantly. On the Eastern Front and in the Middle-East, the areas to be covered were so vast, and the distances from the factories that supplied shells, bullets, concrete and barbed wire so great, that trench warfare in the European style often did not eventuate.

Defensive system

British communication trench, Somme, 1916
British communication trench, Somme, 1916

Early in the war the British defensive doctrine suggested a main trench system of three parallel lines with each line connected by communications trenches. The point at which a communications trench intersected the front trench was of critical importance and was usually heavily fortified. The front trench was lightly garrisoned and typically only occupied in force during "stand to" at dawn and dusk. Between 70 and 100 yards behind the front trench was located the support (or "travel") trench to which the garrison would retreat when the front trench was bombarded. Between 300 and 500 yards further to the rear was located the third reserve trench where the reserve troops could amass for a counter-attack if the front trenches were captured. This defensive layout was soon rendered obsolete as the power of the artillery grew; however in certain sectors of the front, the support trench was maintained as a decoy to attract the enemy bombardment away from the front and reserve lines. Fires were lit in the support line to make it appear inhabited and any damage due to shellfire was immediately repaired.

Aerial view of opposing trench lines. German trenches at the top, British at the bottom
Aerial view of opposing trench lines. German trenches at the top, British at the bottom

Temporary trenches were also built. When a major attack was planned, assembly trenches would be dug near the front trench. These were used to provide a sheltered place for the waves of attacking troops who would follow the first waves leaving from the front trench. "Saps" were temporary, unmanned, often dead-end, utility trenches dug out into no man's land. They fulfilled a variety of purposes such as connecting the front trench to a listening post close to the enemy wire or providing an advanced "jumping-off" line for a surprise attack.

When one side's front line bulged towards the opposition, a "salient" was formed. The concave trench line facing the salient was called a "re-entrant". Large salients were perilous for their occupants because they could be assailed from three sides.

Behind the front system of trenches there were usually at least two more partially prepared trench systems, kilometres to the rear, ready to be occupied in the event of a retreat. The Germans often prepared multiple redundant trench systems; in 1916 their Somme front featured two complete trench systems, one kilometre apart, with a third partially complete system a further kilometre behind. This duplication made a decisive break-through virtually impossible. In the event that a section of the first trench system was captured, a "switch" trench would be dug to connect the second trench system to the still-held section of the first.

The Germans made something of a science out of designing and constructing defensive works. They used reinforced concrete to construct deep, shell-proof, ventilated dugouts as well as strategic strongpoints. They were more willing than their opponents to make a strategic withdrawal to a superior, prepared defensive position. They were also the first to apply the concept "defence in depth" where the front line zone was hundreds of yards deep and contained a series of redoubts rather than a continuous trench. Each redoubt could provide supporting fire to its neighbours and while the attackers had freedom of movement between the redoubts they would be subjected to withering enfilade fire. The British eventually adopted a similar approach but it was incompletely implemented when the Germans launched the 1918 "Spring Offensive" and proved disastrously ineffective.

Trench construction

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Trench construction diagram from a 1914 British infantry manual.

Trenches were never straight but were dug in a square-toothed pattern that broke the line into bays connected by traverses. This meant that a soldier could never see more than 10 metres or so along the trench, consequently the entire trench could not be enfiladed if the enemy gained access at one point or if a bomb or shell landed in the trench, the shrapnel could not travel far. The side of the trench facing the enemy was called the parapet and had a fire step. The rear of the trench was called the parados. The parados protected the soldier's back from shrapnel from shells falling behind the trench. If the enemy captured the trench then the parados would become their "parapet". The sides of the trench were revetted with sandbags, wooden frames and wire mesh. The floor of the trench was usually covered by wooden duckboards.

Dugouts of varying degrees of luxury would be built in the rear of the support trench. British dugouts were usually 8 to 16 feet deep, whereas German dugouts were typically much deeper, usually a minimum of 12 feet deep and sometimes dug 3 stories down with concrete staircases to reach the upper levels.

Australian  using a periscope rifle, Gallipoli 1915
Australian light horseman using a periscope rifle, Gallipoli 1915

To allow a soldier to see out of the trench without exposing his head, a loophole would be built into the parapet. A loophole might simply be a gap in the sandbags or it might be fitted with a steel plate. German snipers used armor-piercing bullets that allowed them to penetrate loopholes. The other means to see over the parapet was the trench periscope — in its simplest form, just a stick with two angled pieces of mirror at the top and bottom. In the Anzac trenches at Gallipoli, where the Turks held the high ground, the periscope rifle was developed to enable the Australians and New Zealanders to snipe at the enemy without exposing themselves over the parapet.

There were three standard ways to dig a trench; entrenching, sapping and tunnelling. Entrenching, where a man would stand on the surface and dig downwards, was most efficient as it allowed a digging party to dig the length of the trench simultaneously. However, entrenching left the diggers exposed above ground and hence could only be carried out when free of observation such as in a rear area or at night. Sapping involved extending the trench by digging away at the end face. The diggers were not exposed but only one or two men could work on the trench at a time. Tunnelling was like sapping except that a "roof" of soil was left in place while the trench line was established then removed when the trench was ready to be occupied. The guidelines for British trench construction stated that it would take 450 men 6 hours (at night) to complete 250 metres of a front line trench system. Thereafter the trench would require constant maintenance to prevent deterioration caused by weather or shelling.

Breastwork "trench," Armentières, 1916
Breastwork "trench," Armentières, 1916

The battlefield of Flanders, which saw some of the worst fighting, presented numerous problems for the practice of trench warfare, especially for the British, who were often compelled to occupy the low ground. In most places, the water table was only a metre or so below the surface, meaning that any trench dug in the ground would quickly flood. Consequently, many "trenches" in Flanders were actually above ground and contructed from massive breastworks of sandbags (actually filled with clay). Initially, both the parapet and parados of the trench were built in this way, but a later technique was to dispense with the parados for much of the trench line, thus exposing the rear of the trench to fire from the reserve line in case the front was breached.

Trench geography

The confined, static and subterranean nature of trench warfare resulted in it developing its own peculiar form of geography. In the forward zone, the conventional transport infrastructure of roads and rail were replaced by the network of trenches and light tramways. The critical advantage that could be gained by holding the high ground meant that minor hills and ridges gained enormous significance. Many slight hills and valleys were so subtle as to have been nameless until the front line encroached upon them. Some hills were named for their height, such as Hill 60. A farmhouse, windmill, quarry or copse of trees would become the focus of a determined struggle simply because it was the largest identifiable feature. However, it would not take the artillery long to obliterate it, so that thereafter it became just a name on a map.

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German stormtroopers supported by a flammenwerfer on the Marne, May 1917

Battlefield features could be given a descriptive name ("Polygon Wood" near Ypres or "Lone Pine"), a whimsical name ("Sausage Valley" and "Mash Valley" on the Somme), a unit name ("Inniskilling Inch" at Helles named for the Royal Inniskilling Fusiliers) or the name of a soldier ("Monash Valley" at Anzac named after General John Monash). Prefixing a feature with "Dead Man's" was also popular for obvious reasons, such as "Dead Man's Road" leading in to Pozières, "Dead Man's Ridge" at Anzac or "Le Mort Homme" at Verdun. There were numerous trench networks named "The Chessboard" or "The Gridiron" due to the pattern they described. For the Australians at Mouquet Farm, the advances were so short and the terrain so featureless that they were reduced to naming their objectives as "points" on the map, such as "Point 81" and "Point 55".

The trenches of the enemy, which would become objectives in an attack, needed to be named as well. Many were named for some observed event such as "German Officers' Trench" at Anzac (where a couple of German officers were sighted) or "Ration Trench" on the Somme (where German ration-carrying parties were sighted). The British gave an alcoholic flavour to the German trenches in front of Ginchy; "Beer Trench", "Bitter Trench", "Hop Trench", "Ale Alley" and "Pilsen Trench". Other objectives were named according to their role in the trench system such as the "Switch Trench" and "Intermediate Trench" on the Somme.

Some sections of the British trench system read like a Monopoly board, with names such as "Park Lane" and "Bond Street". British regular divisions habitually named their trenches after units, which resulted in names such as "Munster Alley" (Royal Munster Fusiliers), "Black Watch Alley" (Black Watch Regiment) and "Border Barricade" (Border Regiment). The Anzacs tended to name features after soldiers ("Plugge's Plateau", "Walker's Ridge", "Quinn's Post", "Johnston's Jolly", "Russell's Top", "Brind's Road" and so forth).

Life in the trenches

An individual soldier's time in the front line trench was usually brief; from as little as one day to as much as two weeks at a time before being relieved. The Australian 31st Battalion once spent 53 days in the line at Villers Bretonneux but such a duration was a rare exception. A typical British soldier's year could be divided as follows:

French trench at Côte 304, Verdun, 1916
French trench at Côte 304, Verdun, 1916
  • 15% front line
  • 10% support line
  • 30% reserve line
  • 20% rest
  • 25% other (hospital, travelling, leave, training courses, etc.)

Even when in the front line, the typical soldier would only be called upon to engage in fighting a handful of times a year — making an attack, defending against an attack or participating in a raid. The frequency of combat would increase for the men of the "elite" fighting divisions — on the Allied side; the British regular divisions, the Canadian Corps, the French XX Corps and the Anzacs.

Some sectors of the front saw little activity throughout the war, making life in the trenches comparatively easy. When the I Anzac Corps first arrived in France in April 1916, after the evacuation of Gallipoli, they were sent to a relatively peaceful sector south of Armentières to "acclimatise". Other sectors were in a perpetual state of violent activity. On the Western Front, Ypres was invariably hellish, especially for the British in the exposed, overlooked salient. However, quiet sectors still amassed daily casualties through sniper fire, artillery and gas. In the first six months of 1916, before the launch of the Somme Offensive, the British did not engage in any significant battles on their sector of the Western Front and yet suffered 107,776 casualties.

A sector of the front would be allocated to an army corps, usually containing three divisions. Of these two would occupy adjacent sections of the front and the third would be in rest to the rear. This break down of duty would continue down through the army structure so that within each front line division, typically containing three infantry brigades, two brigades would occupy the front and the third would be in reserve. Within each front line brigade, typically containing four battalions (regiments for the Germans), two battalions would occupy the front with two in reserve. And so on for companies and platoons. The lower down the structure this division of duty proceeded, the more frequently the units would rotate from front line duty to support or reserve.

Chateau Wood, Ypres, 1917
Chateau Wood, Ypres, 1917

During the day, snipers and artillery observers in balloons made movement perilous so the trenches were mostly quiet. Consequently, the trenches were busiest at night when cover of darkness allowed the movement of troops and supplies, the maintenance and expansion of the barbed wire and trench system, and reconnaissance of the enemy's defences. Sentries in listening posts out in no man's land would try to detect enemy patrols and working parties or indications that an attack was being prepared.

Raids were carried out in order to capture prisoners and "booty" — letters and other documents that provide intelligence about the unit occupying the opposing trenches. As the war progressed, raiding became part of the general British policy, the intention being to maintain the fighting spirit of the troops and to deny No-Man's Land from the Germans. Such dominance was achieved at a high cost and a post-war British analysis concluded that the benefits were probably not worth the price.

Early in the war, surprise raids would be mounted, particularly by the Canadians, but increased vigilance made achieving surprise difficult as the war progressed. By 1916, raids were carefully planned exercises in combined arms and involved close cooperation of infantry and artillery. A raid would begin with an intense artillery bombardment designed to drive off or kill the front trench garrison and cut the barbed wire. Then the bombardment would shift to form a "box", or cordon, around a section of the front line to prevent a counter-attack intercepting the raid.

Death in the trenches

The intensity of World War I trench warfare meant that about 10% of the fighting soldiers were killed. This compared to 5% killed during the Boer War and 4.5% killed during World War II. For British and Dominion troops serving on the Western Front, the proportion of killed was 12% while the total proportion of troops who became casualties (killed or wounded) was 56%. Considering that for every front-line infantryman there were about 3 soldiers in support (artillery, supply, medical, etc.) it was highly unlikely for a fighting soldier to survive the war without sustaining some form of injury. Indeed many soldiers were injured more than once during the course of their service.

Medical services were primitive and life-saving antibiotics undiscovered. Relatively minor injuries could prove fatal through the onset of infection and gas gangrene. The Germans recorded that 12% of leg wounds and 23% of arm wounds resulted in death, mainly through infection. The Americans recorded that 44% of casualties that developed gangrene died. Half of those who were wounded in the head died and only 1% of those wounded in the abdomen survived.

Three quarters of the wounds inflicted during the war came from shell fire. The wound resulting from a shell fragment was usually more traumatic than a gunshot wound. A shell fragment would often introduce debris making it more likely that the wound would become infected. These factors meant that a soldier was three times more likely to die from a shell wound to the chest than from a gunshot wound. The blast from shell explosions could also kill by concussion. In addition to the physical effects of shell fire there was the psychological damage. Men who had to endure a prolonged bombardment would often suffer debilitating shell shock, a condition that was not well understood at the time.

As in many other wars, World War I's greatest killer was disease. Sanitary conditions in the trenches were quite poor, and common infections included dysentery, typhus, and cholera. Many soldiers suffered from parasites and related infections. Poor hygiene also led to conditions such as trench mouth and trench foot. Another common killer was exposure, since the temperature within a trench in the winter could easily fall below zero degrees celsius.

Burial of the dead was usually a luxury that neither side could easily afford. The bodies would lie in no man's land until the front line moved, by which time the bodies were often unidentifiable. On some battlefields, such as at the Nek in Gallipoli, the bodies were not buried until after the war. On the Western Front, bodies continue to be found as fields are ploughed and building foundations dug.

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Stretcher bearers, Passchendale, August 1917

At various times during the war—particularly early on—official truces were organised so that the wounded could be recovered from no man's land and the dead could be buried. Generally though, the higher commands disapproved of any slackening of the offensive for humanitarian reasons and so ordered their troops not to permit enemy stretcher bearers to operate in no man's land. However, this order was almost invariably ignored by the soldiers in the trenches, who knew that it was to the mutual benefit of the fighting men of both sides to allow the wounded to be retrieved. So, as soon as hostilities ceased, parties of stretcher bearers, marked with Red Cross flags, would go out to recover the wounded, sometimes swapping enemy wounded for their own. There were occasions when this unofficial cease fire was exploited to conduct a reconnaissance or to reinforce or relieve a garrison.

Weapons of trench warfare

Infantry weapons

The common infantry soldier had three weapons at his disposal in the trenches: the rifle, bayonet, and grenade.

The standard British rifle was the .303 Short Magazine Lee-Enfield, which was originally developed as a cavalry carbine and had an effective range of 1400 yards, though in the hands of the average soldier, 200 yards was about the limit of accurate fire. British infantry training emphasised rapid fire rifle shooting rather than accuracy. Early in the war, the British were able to defeat German attacks at Mons and the First Battle of Ypres using massed rifle fire, but as trench warfare developed, opportunities to assemble a line of riflemen became rare.

The British soldier was equipped with a 21-inch sword bayonet, which was too long and unwieldy to be particularly effective in close quarters combat. However, bayonet use was safer than firing the rifle which, in a melee, might strike an ally instead of an enemy. British figures recorded that only 0.3% of wounds were caused by bayonets, however, a strike from a bayonet was highly likely to result in death. A bayonet charge could be effective at inducing terror in an opponent, encouraging them to flee or surrender. The bayonet was used to finish off wounded enemy during an advance, saving ammunition while reducing the possibility of being attacked from the rear.

Many soldiers preferred a short handled spade or entrenching tool over a bayonet. They would sharpen the blade to a knife edge so it was just as effective as a bayonet and the shorter length made them handier to use in the confined quarters of the trenches. These tools could then be used to "dig in" after they had taken a trench.

The grenade came to be the primary infantry weapon of trench warfare. Both sides were quick to raise specialist bombing squads. The grenade enabled a soldier to engage the enemy indirectly (without exposing himself to fire) and it did not require the precise accuracy of rifle fire in order to kill or maim. The Germans and Turks were well equipped with grenades from the start of the war, but the British, who had ceased using grenadiers in the 1870s and did not anticipate a siege war entered the conflict with virtually none, such that soldiers had to improvise bombs with whatever was available. By late 1915, the British Mills bomb had entered wide circulation, and by the end of the war 75 million of them had been used.

Machine guns

The machine gun is perhaps the signature weapon of trench warfare, with the image of ranks of advancing infantry being scythed down by the withering hail of bullets. The Germans embraced the machine gun from the outset—in 1904, every regiment was equipped with one machine gun—and the machine gun crews were the elite infantry units. After 1915, the MG 08/15 was the standard-issue German machine gun; its number entered the German language as an idiomatic expression for "dead plain". At Gallipoli and in Palestine the Turks provided the infantry, but it was usually Germans who manned the machine guns.

The British High Command were less enthusiastic about machine gun technology, supposedly considering the weapon too "unsporting", and they lagged behind the Germans in adopting the weapon. In 1915 the Machine Gun Corps was formed to train and provide sufficient heavy machine gun teams. To match demand, production of the Vickers machine gun was contracted to firms in the United States. By 1917, every company in the British forces was also equipped with four light Lewis machine guns, which significantly enhanced their firepower.

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Vickers machine gun

The heavy machine gun was a specialist weapon, and in a static trench system was employed in a scientific manner, with carefully calculated fields of fire, so that at a moment's notice an accurate burst could be laid upon the enemy's parapet or at a break in the wire. Equally it could be used as light artillery in bombarding distant trenches. Heavy machine guns required teams of up to eight to move them, maintain them and keep them supplied with ammunition.


Mortars, which lobbed a shell a relatively short distance, were widely used in trench fighting for harassing the forward trenches and for cutting wire in preparation for a raid or attack. In 1914, the British fired a total of 545 mortar shells. In 1916, they fired over 6,500,000 shells.

The main British mortar was the Stokes mortar, which was the precursor of the modern mortar. It was a light mortar, but was easy to use, and capable of a rapid rate of fire by virtue of the propellant cartridge being attached to the shell. To fire the Stokes mortar, the round was simply dropped into the tube, where the cartridge was ignited automatically when it struck the firing pin at the bottom.

The Germans used a range of mortars. The smallest were grenade-throwers (granatenwerfer) which fired "pineapple" bombs. Their medium trench-mortars were called mine-throwers (minenwerfer), dubbed "minnies" by the British. The heavy mortar was called the ladungswerfer which threw "aerial torpedoes", containing a 200 lb (90 kg) charge, over 1000 yards. The flight of the missile was so slow and leisurely that the men on the receiving end could make some attempt to seek shelter.


Artillery dominated the battlefield of trench warfare in the same way the air power dominates the modern battlefield. An infantry attack was rarely successful if it advanced beyond the range of its supporting artillery. In addition to bombarding the enemy infantry in the trenches, the artillery would engage in counter-battery duels to try to destroy the enemy's guns.

Artillery mainly fired shrapnel, high explosives or, later in the war, gas shells. The British experimented with firing incendiary "thermite" shells to set trees and ruins alight.

Loading a 15-in howitzer
Loading a 15-in howitzer

Artillery pieces were of two types; guns and howitzers. Guns fired high velocity shells over a flat trajectory and were often used to deliver shrapnel and to cut barbed wire. Howitzers lofted the shell over a high trajectory such that it plunged into the ground. The biggest artillery were usually howitzers. The German 420 howitzer weighed 20 tons and could fire a one ton shell over six miles.

A critical feature of modern artillery pieces was the hydraulic recoil mechanism which meant that the gun did not need to be re-aimed after each shell was fired. Initially each gun would need to register its aim on a known target, in view of an observer, in order to fire with precision during a battle. The process of gun registration would often alert the enemy that an attack was being planned. Towards the end of 1917, artillery techniques were developed enabling guns to be aimed accurately without the need for registration.


See main article: Use of poison gas in World War I

Tear gas was first employed in August 1914 by the French but this could only disable the enemy. In April 1915, chlorine was first used by Germany at the Second Battle of Ypres. A large enough dose could kill but the gas was easy to detect by scent and sight. Those that were not killed on exposure could suffer permanent lung damage.

Phosgene, first used in December 1915, was the ultimate killing gas of World War I — it was 18 times more powerful than chlorine and much more difficult to detect. However, the most effective gas was mustard gas, introduced by Germany in July 1917. Mustard gas was not as fatal as phosgene but it was hard to detect and lingered on the surface of the battlefield and so could inflict casualties over a long period. The burns it produced were so horrific that a casualty resulting from mustard gas exposure was unlikely to be fit to fight again. Only 2% of mustard gas casualties died, mainly from secondary infections.

The first method of employing gas was by releasing it from a cylinder when the wind was favourable. Such an approach was obviously prone to miscarry if the direction of the wind was misjudged. Also the cylinders needed to be positioned in the front trenches where they were liable to be ruptured during a bombardment. Later in the war, gas was delivered by artillery or mortar shell.


During the first year of the war, none of the combatant nations equipped their troops with steel helmets. Soldiers went into battle wearing simple cloth or leather caps that offered virtually no protection from the damage caused by modern weapons. German troops were wearing the traditional leather pickelhaube (spiked helmet), with a covering of cloth to protect the leather from the splattering of mud. Once the war entered the phase of trench warfare, the number of lethal head wounds that troops were receiving from shrapnel increased dramatically.

The French were the first to see a need for greater protection and began to introduce the first steel helmets in the summer of 1915. The Adrian helmet (designed by August-Louse Adrian) replaced the traditional French kepi and was later adopted by the Belgian and Italian armies.

At about the same time the British were developing their own helmets. The French design was rejected as not strong enough and too difficult to mass-produce. The design that was eventually approved by the British was the Brodie helmet (designed by John L. Brodie) This British helmet had a wide brim to protect the wearer from falling objects but offered less protection to the neck of the wearer. When they entered the war, this was the helmet chosen by the Americans.

The traditional German pickelhaube was replaced by the stahlhelm or "coal-scuttle helmet" in 1916. Some elite Italian units used a helmet derived from ancient Roman designs.

None of these standard helmet could protect the face or eyes, however. Special face-covers were designed to be used by machine-gunners, and the Belgians tried out goggles made of louvres to protect the eyes.


The use of barbed wire was decisive in slowing infantry travelling across the battlefield. Without it, fast moving infantry (or cavalry) might cross the lines and reach the enemy machine gun posts and artillery. Slowed down by the barbed wire, they were much more likely to be shot down by the machine guns or infantry men. Liddell Hart identified barbed wire and the machine gun as the elements that had to be broken to regain a mobile battlefield.


The fundamental purpose of the aircraft in trench warfare was reconnaissance and artillery observation. The role of the fighter was to protect his own reconnaissance aircraft and to destroy those of the enemy, or at least deny them the freedom of his airspace. This involved achieving air superiority over the battlefield by destroying the enemy's fighters as well. Spotter aircraft would monitor the fall of shells during registration of the artillery. Reconnaissance aircraft would photograph trench lines, monitor enemy troop movements, and locate enemy artillery batteries so that they could be destroyed with counter-battery fire.

The Germans employed flame throwers (flammenwerfer) during the war but the technology was not mature so they were more effective at inducing terror than inflicting casualties.


All sides would engage in vigorous mining and counter-mining duels. The dry chalk of the Somme was especially suited to mining but with the aid of pumps it was also possible to mine in the sodden clay of Flanders. Specialist tunnelling companies, usually made up of men who had been coal miners in civilian life, would dig tunnels under no man's land and beneath the enemy's trenches. These mines would then be packed with explosives and detonated, producing a large crater. The crater served two purposes; it could destroy or breach the enemy's trench and, by virtue of the raised lip that they produced, could provide a ready-made "trench" closer to the enemy's line. When a mine was detonated, both sides would race to occupy and fortify the crater.

If the miners detected an enemy tunnel in progress, they would often drive a counter-tunnel, called a camouflet, which would be detonated in an attempt to destroy the other tunnel prematurely. Night raids were also conducted with the sole purpose of destroying the enemy's mine workings. On occasions mines would cross and fighting occur underground.

The mining skills could also be used to move troops unseen. On one occaision a whole division was moved through interconnected workings and sewers without German observation.

The British detonated a number of mines on July 1, 1916, the first day of the Battle of the Somme. The largest mines—the Y Sap Mine and the Lochnager Mine—each containing 24 tons of explosives, were blown near La Boiselle, throwing earth 4,000 feet into the air.

At 5.10 AM on June 7, 1917, 19 mines were detonated by the British to launch the Battle of Messines. The average mine contained 21 tons of explosive and the largest, 125 feet beneath St. Eloi, was twice the average at 42 tons. The combined force of the explosions was supposedly felt in England. As the Chief of Staff of the British Second Army, General Sir Charles Harrington, commented on the eve of the battle:

I do not know whether we shall change history tomorrow, but we shall certainly alter the geography.

The craters from these and many other mines on the Western Front are still visible today. Three further mines were laid for Messines but were not detonated as the tactical situation had since changed. One blew during a thunderstorm in 1955; the other two remain to this day.

Trench battles


The fundamental strategy of trench warfare was to defend your own position strongly while trying to achieve a breakthrough into the enemy's rear. The effect was to end up in attrition; the process of progressively grinding down the opposition's resources until, ultimately, they are no longer able to wage war. This did not prevent the ambitious commander from pursuing the strategy of annihilation—the ideal of an offensive battle which produces victory in one decisive engagement. The Commander in Chief of the British forces, General Douglas Haig, was constantly seeking a "breakthrough" which could then be exploited with cavalry divisions. His major trench offensives—the Somme in 1916 and Flanders in 1917—were conceived as breakthrough battles but both degenerated into costly attrition. The Germans actively pursued a strategy of attrition in the Battle of Verdun, the sole purpose of which was to "bleed the French Army white". At the same time the Allies needed to mount offensives in order to draw attention away from other hard-pressed areas of the line.


The popular image of a trench warfare infantry assault is of a wave of soldiers, bayonets fixed, going "over the top" and marching in a line across no man's land into a hail of enemy fire. This indeed was the standard method early in the war and successful examples are few. The more common tactic was to attack at night from an advanced post in no man's land, having cut the barbed wire entanglements beforehand.

In 1917, the Germans innovated with the "infiltration" tactic where small groups of highly trained and well equipped troops would attack vulnerable points and bypass strong points, driving deep into the rear areas. The distance they could advance was still limited by their ability to supply and communicate.

Missing image
Passchendaele village, before and after the 3rd Battle of Ypres

The role of artillery in an infantry attack was twofold; firstly in preparation by killing or driving off the enemy garrison and destroying his defences, and secondly in protecting the attacking infantry by providing an impenetrable "barrage" or curtain of shells to prevent an enemy counter-attack. The first attempt at sophistication was the "lifting barrage" where the first objective of an attack was intensely bombarded for a period before the entire barrage "lifted" to fall on a second objective farther back. However, this usually expected too much of the infantry and the usual outcome was that the barrage would outpace the attackers, leaving them without protection. This resulted in the use of the "creeping barrage" which would lift more frequently but in smaller steps, sweeping the ground ahead and moving so slowly that the attackers could usually follow closely behind it.

Capturing the objective was half the successful battle—the battle was only won if the objective was held. The attacking force would have to advance with not only the weapons required to capture a trench but also the tools—sandbags, picks & shovels, barbed wire—to fortify and defend from counter-attack. The Germans placed great emphasis on immediately counter-attacking to regain lost ground. This strategy cost them dearly in 1917 when the British started to limit their advances so as to be able to meet the anticipated counter-attack from a position of strength.


The main difficulty faced by an attacking force in a trench battle was reliable communications. Wireless communications were still in their infancy so the available methods were telephone, semaphore, signal lamps, carrier pigeons and runners, none of which were particularly reliable. Telephone was the most effective but the lines were extremely vulnerable to shell fire so would usually be cut early in a battle. In an attempt to counter this, telephone lines would be laid in a ladder pattern to provide multiple redundant paths. Flares and rockets were used to signal an objective was reached or to call for pre-arranged artillery support.

It was not unusual for a battalion or brigade commander to wait 2 or 3 hours for word on the progress of an attack, by which time any decision made based on the message would probably be long out of date. A similar period would pass when transferring the news to the division, corps and army headquarters. Consequently the outcome of many trench battles were decided by the company and platoon commanders in the thick of the fighting.


With the withdrawal of Russia from World War I, the Germans were able to reinforce their western front with troops from the eastern front. This allowed them to take units out of the line and train them in new methods and tactics as stormtroopers. The new methods involved men rushing forward in small groups using whatever cover was available and laying down covering fire for other groups in the same unit as they moved forward. The new tactics (intended to achieve surprise) were to bypass strongpoints and attack the weakest parts of an enemy's line. Additionally, they acknowledged the futility of managing a grand detailed plan of operations from afar, opting instead for junior officers on the spot to exercise initiative. These tactics proved very successful during the German 1918 Spring Offensive against Allied forces.

Trench warfare is a static battle, ruled by machine gun and wire. The tank was developed to break this stranglehold. From its first outings the tank showed that the trenches could be broken. More and better tanks including the first light tanks appeared during the war on the Western front.

During the last 100 days of World War I the British forces broke through the German trench system and harried the Germans back toward Germany using infantry supported by tanks and close air support. Between the two world wars these techniques were used by J.F.C. Fuller and B.H. Liddell Hart to develop theories about a new type of warfare. The ideas were picked up by the Germans who developed them further and put them into practice with the use of Blitzkrieg. Blitzkrieg relied on the concentration of armor launched at a narrow front to make the breakthrough followed by a high speed encirclement of the enemy's front line. Armor was supported by close air support with airmen inserted into army units to direct tactical air strikes.

The stunning victories by the Germans early in World War II using blitzkrieg showed that fixed fortifications like the Maginot Line could be bypassed. The amphibious landing (combined with aircover and landings behind the line) by the Western Allies in 1944 broke through the incomplete Atlantic Wall with relative ease. The fight inland through the bocage proved far more of an obstacle than the fixed fortifications of the Atlantic Wall.

Combined arms tactics (where infantry, artillery, armor and aircraft operate in close cooperation) made trench warfare obsolete. The foundation of modern land warfare lies in semi-autonomous small teams (such as the fire team) and places a large emphasis on rapid communication and allowing smaller units to exercise initiative.

This is not to say that entrenchment is redundant. It is still a valuable method for reinforcing natural obstacles to create a line of defence. At the start of the Battle of Berlin, the last major assault of World War II, the Russians attacked over the river Oder against German troops dug in on the Seelow Heights which are about 50 km east of Berlin. Entrenchment allowed the Germans, who were massively outnumbered, to survive a barrage from the largest concentration of artillery in history; it also allowed the Germans to inflict tens of thousands of casualties on the Soviets, thanks to the marshy land which lay between the river and the heights, before being driven west.

Recent trench warfare

Missing image
US Marines of Company B, Battalion Landing Team, 1st Battalion, 4th Marines, 11th Marine Expeditionary Unit, perform a trench clearing exercise in Camp Pendleton, Jan. 7, 2004

Trench warfare has been very infrequent since the end of World War I. When two large armored armies meet, the result has generally been mobile warfare of the type which developed in World War II.

The most cited example of trench warfare after World War I was the Iran-Iraq War in which both armies had a large number of infantry with modern small arms, but very little armor, aircraft or training in combined weapons. The result was very similar to World War I with trenches and chemical warfare used.

Another example of trench stalemate was the Eritrean-Ethiopian War of 19982002. The frontline in Korea and the front lines between Pakistan and India in Kashmir, are two examples of demarcation lines which could become hot at any time. They consist of miles trenches linking fortified strong points and in Korea surrounded by millions of land mines.


  • Death's Men: Soldiers of the Great War, Denis Winter, 1978, ISBN 0-14-016822-2
  • History Of The First World War, B H Liddell Hart, (1930, 1934, 1970)

See also

External links

fr:Tranchée nl:Loopgraaf ms:Perperangan parit ja:塹壕


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