By the end of 1914, both sides had constructed trench systems stretching from the English Channel to Switzerland. (a) Describe the typical features of a tre...

(a) Typical features of a trench system [4 marks]

Trench systems on the Western Front were constructed in multiple parallel lines: a front-line (or fire) trench faced no man's land, behind which lay support trenches and reserve trenches, all connected by communication trenches running perpendicular to the front. Trenches were built in a zigzag or "traverse" pattern to limit the damage from shell blasts and to prevent an enemy who entered the trench from firing straight down its length (enfilade fire). Barbed wire entanglements were placed in front of the trenches to slow attacking infantry and channel them into killing zones. Dugouts and underground shelters were constructed to protect soldiers from artillery bombardment, with the Germans building particularly deep and elaborate dugouts.

(b) Why it was so difficult to break through enemy trench lines [6 marks]

Multiple factors made breakthrough extraordinarily difficult. Machine guns could fire hundreds of rounds per minute, cutting down infantry crossing the open ground of no man's land with devastating efficiency. Barbed wire entanglements slowed attackers and forced them into concentrated groups that were easier to target. Pre-attack artillery bombardments warned defenders of an imminent assault, eliminating the element of surprise. Even when the first trench line was captured, attackers then faced second and third lines of defence, and defenders could launch immediate counter-attacks. Attackers advanced beyond the range of their own artillery support, while defenders could bring up reinforcements rapidly using intact communication trenches and railways behind their lines. The muddy, shell-cratered terrain of no man's land made rapid movement physically impossible.

(c) How far trench warfare favoured the defending side [10 marks]

Defence was strongly favoured:

• Defenders were protected by fortified positions, concrete bunkers, and underground shelters, while attackers had to cross open ground under fire.
• Machine guns and artillery gave an enormous firepower advantage to the side holding its ground.
• Reserves could be brought forward quickly by defenders using rail and communication trenches, while attackers had to cross devastated, cratered ground, stretching supply lines.
• The deeper an advance went, the more vulnerable and overextended the attacker's position became, making counter-attacks increasingly effective.

However, defence was not without disadvantages:

• Defenders suffered enormous casualties from constant artillery bombardment, which could destroy positions and cause severe psychological strain ("shell shock").
• Gas attacks and mining operations (tunnelling beneath enemy trenches and detonating explosives) threatened defenders in their positions.
• The development of new offensive tactics gradually shifted the balance: creeping barrages, combined arms coordination, and infiltration ("stormtrooper") tactics gave attackers methods to breach defences.
• By 1918, the combination of tanks, aircraft, improved artillery coordination, and battle-hardened infantry (particularly in the Hundred Days Offensive) allowed the Allies to overcome trench defences.

Trench warfare overwhelmingly favoured the defence for most of the war, which is the fundamental explanation for the stalemate. By 1918, tactical innovation tipped the balance back toward the attack, but only after four years of costly learning.