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Trench warfare, that enduring
symbol of the Great War, was the product of a century of
political, economic, social and cultural development that
transformed the military art. The large increase in Europe's
population between 1800 and 1900 provided ample manpower for
the new mass armies, while industry developed and produced
in vast numbers new and deadly weapons of war: the magazine
rifle, the machine gun and the breach-loaded
recoil-stabilized cannon. Modern methods of administration
and finance facilitated national mobilization and
conscription, and enabled the armies to be supplied and
maintained in the field indefinitely. Strategic mobility
(the ability to move large bodies of troops from area to
area) was provided by the railroad and an increasingly dense
road net.
But once on the battlefield itself
the armies of 1914 were no more mobile than those of the
Napoleonic wars, moving on foot or horseback. Low mobility
and high firepower gave the defender an overwhelming
advantage, especially once the armies’ leaders grasped the
value of entrenchment. Even the most hastily constructed
field fortifications multiplied a soldier’s chances of
survival in combat—thus the trench systems on both sides
grew increasingly elaborate and complex. Moreover, the rival
armies were fighting over the same small area of Western
Europe where so many wars of the eighteenth and nineteenth
centuries had been fought. But now they were many times
larger, armed with much more lethal weapons, supported by
mobilized national economies. The result, as indeed a few
military thinkers had foreseen before 1914, was tactical,
hence strategic, stalemate.
After the brief period of mobile
warfare in 1914, trench warfare on the Western Front settled
into a fairly standard pattern. On both sides the defense
was usually based on three lines of trenches: a forward
line, a support line and a rear line. The trenches were dug
in a zigzag traverse pattern—this to prevent attackers in
occupation of one section from firing straight down the
trench—with firing steps for riflemen plus
protected positions for machine guns and observation posts.
Dugouts in the rear face of each trench provided
accommodation for company and battalion headquarters, supply
dumps, and shelter from artillery bombardment. The
front-line trench was protected by barbed-wire entanglements
many yards deep; the support line and the rear line served
as assembly points for reserves and fallback positions for
the front-line troops. The trenches were connected to one
another and to the rear area by communications trenches.
These enabled troops and supplies to be moved back and forth
without exposure to enemy observation and fire.
British troops in a
front-line trench (Imperial War Museum)
Behind the trench lines were troop
billets, artillery positions and brigade headquarters.
Farther back still were division and corps headquarters,
large supply dumps, rest camps, field hospitals—all the
supporting infrastructure required by modern armies.
Infantry battalions typically rotated between the trenches,
the billets and the rest camps. In sectors where an
offensive was to take place, the rear areas of both sides
would become crowded with reserves and vast quantities of
supplies—especially the hundreds of thousands of rounds of
artillery ammunition deemed necessary to support or resist
the “big push.”
Senior commanders on both sides
realized the inherent power of trench defenses, but that did
not lead them to conclude that offensive action was futile.
The search therefore began for some means of breaking the
trench stalemate, and the most obvious solution seemed to be
firepower. On the Allied side, the generals reasoned that
with enough artillery the enemy’s trench defenses could be
battered down, opening a way to the green fields beyond. The
costly and unsuccessful Allied offensives on the Western
Front in 1915 and 1916, culminating with the horrific Battle
of the Somme, only served to confirm this view. The attacks,
it was argued, had failed because the supporting artillery
was insufficient. More was needed—enough to physically
annihilate the enemy’s defense system in the sector of the
attack.
In fact, however, the French and
British generals had misdiagnosed the problem that
confronted them.
It was certainly possible to break
into the enemy's defenses, capturing a few lines of
trenches, and indeed this happened fairly often. But it
proved extraordinarily difficult to convert such a break-in
to a full breakthrough. One obvious problem was that the
laborious preparations for a major attack were easy to
detect, so that the element of surprise was lacking. Thus
forewarned, the defender had ample time to reinforce the
threatened sector. And once the offensive began, the
attacking troops of the first wave could be expected to do
no more than make good the break-in—an effort that would
decimate and exhaust them. The transition to a full
breakthrough required the commitment of reserves—and the
defender’s advantage in the management of reserves was the
real reason for the costly failure of all offensives
attempted by the Allies between 1914 and 1917.
Department of History,
USMA West Point
Before sending their reserves
forward, the generals at their division, corps and army
headquarters needed accurate information from the front-line
units: Where had the attack succeeded; where had it failed?
But such information was slow to arrive. The primitive
radios of the day were too cumbersome to carry forward with
the attacking troops, telephone lines were all too easily
cut by shellfire, messengers could be killed, wounded, or
simply become lost. And when accurate information finally
did come to hand, the attacker’s reserves had to struggle
forward over ground devestated by prolonged
artillery bombardment. Meantime the defender could shift
reserves quickly by road and rail to the threatened sector
of his front. For both sides the battle became a race
against time—a race usually won by the defender.
But if the attacker suffered heavy casualties for nugatory gains, it was also
true that the price of a successful defense was high.
Holding the front-line trenches meant packing them with
troops, who were therefore exposed for a prolonged period to
the fury of bombardment. The Battle of the Somme in the
summer of 1916 is remembered as a disaster for the British
Army; less often remarked upon is its effect on the German
Army. The precise toll on the German side is still a matter
of some dispute, but a figure of 500,000 total casualties
cannot be far from the mark. Toward the end of the battle,
reports reaching OHL (the Supreme Command) indicated that
the Somme defenses were close to collapse, the trench system
itself in poor condition, the troops manning it worn out and
dispirited.
The Germans thus realized
that a new scheme of defense was required, and with
characteristic efficiency and attention to detail they
created one that proved highly effective in the conditions
prevailing on the Western Front. Having studied the tactical
lessons of the Russo-Japanese War (1904-05), the German Army
had been the first to appreciate the value of field
fortifications and they took advantage of wartime experience
to further refine their methods. In the new defensive system
that the German Army began to develop in 1916, strongly
garrisoned linear trenches were no longer to be the
principal fighting positions. The forward line of defense
was now an outpost position, lightly held, whose function
was to identify the attacker’s axis of advance and slow him
down. The troops manning this outpost line occupied small
dugouts, sited so as to take advantage of natural terrain
features, and were connected to the rear area by
communications trenches.
British heavy artillery in
action (Imperial War Museum)
The main defensive zone was based
on a series of mutually supporting strongpoints, held in
platoon or company strength, sited to dominate all avenues
of approach. Advancing between them, the attacking infantry
found themselves exposed to withering rifle and machine gun
fire, supplemented by pre-registered artillery and mortar
barrages. The strongpoints were constructed of
steel-reinforced concrete, making them invulnerable to all
but a direct hit by heavy artillery. Throughout the
defensive zone, barbed-wire entanglements and other
obstacles were sited to slow the enemy down and prolong his
exposure to the defenders’ fire. Behind the zone of
strongpoints the Germans posted local reserves usually in
company or battalion strength, whose task was to launch
immediate counterattacks against any enemy troops who
threatened to capture ground essential for the maintenance
of the defense. Finally, there was the general
reserve: so-called relief divisions
(Ablösungsdivisionen),
standing by in readiness to mount a full-scale counterattack
if necessary.
The depth of the main defensive zone was from three to four
and a half miles, depending on the terrain.
To streamline command and control,
the front was divided into sectors, in each of which a corps
headquarters was made responsible for administrative and
logistical tasks. Divisions were rotated in and out of these
sectors as necessary, with tactical control devolved upon
regimental and battalion commanders (Kampftruppenkommandeur)
in the battle zone. These commanders were given
discretion to maneuver their troops as necessary to deliver
local counterattacks or evade enemy fire.
Further enhancing the effectiveness
of their defensive system, the Germans were usually willing
to yield ground that might be difficult to defend, siting
their positions on the most advantageous terrain. In 1917
they even carried out a large-scale withdrawal from the
Somme to the Siegfriedstellung
(Siegfried Position), called the Hindenburg Line by the
Allies. This position, which became the keystone of the
German defenses on the Western Front, embodied all the
principles mentioned above and took five months to
construct. Though commanders were by no means agreed as to
the advisability of abandoning the Somme line, the course of
the battle from September to November seemed to leave no
other option. In March 1917 the withdrawal to the
Siegfriedstellung, code-named
Alberich Bewegung
(Operation Alberich) after
the evil dwarf in the
Nibelungenlied,
was carried out in good order. It shortened the
German line by some 25 miles, enabling a dozen
divisions to be taken out of the front as reserves. Similar
defensive positions were established for other sectors of
the front in preparation for the anticipated defensive
battles of 1917, for instance the
Flandernstellung in Belgium. The new system of
defense proved highly effective, frustrating the French and
British offensives on the Aisne and in Flanders. Though they
scored some tactical successes in the former offensive the
Allies were unable to achieve a breakthrough, and they
suffered 350,000 casualties against 163,000 inflicted on the
Germans—a disappointment that touched off a large-scale
mutiny in the ranks of the French Army. In Flanders, the
Third Battle of Ypres was ended on a similar note of
frustration.
The German withdrawal to
the Siegfried
Position, indicated by the dashed line (Wikimedia Commons)
In 1918 the trench deadlock on the
Western Front was finally broken, first by by the German
Army's new tactics (the hurricane artillery bombardment,
specially trained assault troops, combined-armed battle
groups), then by the Allies’ employment of the
tank on a
large scale against an exhausted enemy. In both cases, the
effect was to restore tactical battlefield mobility. But
though a few visionary military thinkers perceived that
those final battles heralded another revolution in the art
of war, the memory of the Western Front’s blood-soaked,
trench-scarred battlefields remained dominant in the minds
of soldiers, politicians and the European peoples for the
next twenty years. One of them was a German soldier who’d
served in the trenches for four years, and who on Armistice
Day was lying in a military hospital, having been blinded by
mustard gas. His name was Adolf Hitler.
Adolf Hitler (right) and
comrades of the 16th Bavarian Reserve Infantry Regiment,
circa 1916 (Bundesarchiv)
