Key topic 3 · The Schlieffen Plan and deadlock on the Western Front

What a Grade 9 answer knows here. Haig is the specification's built-in interpretation question, which is why it belongs to the paper that assesses AO4. The strongest answers do not defend or attack him; they ask what a commander in 1916 could have known and what alternative was actually available, which is what 'in the context of historical events studied' means.

3 lessons, each answering one essential question with the story, the dates that earn marks, the people to place, how historians disagree and the cap in the mark scheme that bites. Completely free.

The 3 lessons

The Schlieffen Plan and why it failed

Did the plan fail at Liège, at the Marne, or on the day it assumed Russia would need six weeks? After 1894 Germany faced war on two fronts against France and Russia simultaneously.

Examined through causation and consequence. Learn the Schlieffen Plan and why it failed →

Trenches, new weapons and the reasons for deadlock

Why could an attack break into a trench system and never break through it? Everything available in 1914 favoured the defender.

Examined through causation and continuity. Learn trenches, new weapons and the reasons for deadlock →

The Somme, Passchendaele and the responsibility of Haig

What could a commander in 1916 have known, and what alternative did he actually have? The offensive was agreed at Chantilly in December 1915 as a joint Anglo-French attack, and its shape changed when the German assault on Verdun in February 1916 consumed the French army…

Examined through significance and consequence. Learn the Somme, Passchendaele and the responsibility of Haig →

The dates that earn marks in this key topic

Two from each lesson, in the order the topic is taught — each with the reason it is worth a mark, and the lesson that places it.

1905 — Schlieffen's memorandum.: The document the plan is reconstructed from, and the object of the historiographical dispute. (The Schlieffen Plan and why it failed)
4–16 August 1914 — Liège holds for about eleven days.: The first delay, and it is measured in days rather than the weeks often claimed. (The Schlieffen Plan and why it failed)
November 1914 — The line reaches the Channel; there is no flank left.: Deadlock begins as a geographical fact rather than a tactical failure. (Trenches, new weapons and the reasons for deadlock)
April 1915 — First large-scale use of chlorine gas at Second Ypres.: The first attempt at a technological solution, and respirators followed within months. (Trenches, new weapons and the reasons for deadlock)
February–December 1916 — Verdun; the French army is consumed and the Somme's purpose changes.: The Somme cannot be judged without Verdun, because relief of Verdun became its main purpose. (The Somme, Passchendaele and the responsibility of Haig)
1 July 1916 — About 57,470 British casualties, 19,240 killed.: The worst day in British military history, and the figure must be given accurately. (The Somme, Passchendaele and the responsibility of Haig)

The people to place

Alfred von Schlieffen — Chief of staff to 1906; author of the 1905 memorandum. (The Schlieffen Plan and why it failed)
Helmuth von Moltke the Younger — Modified the plan and lost control of it; replaced after the Marne. (The Schlieffen Plan and why it failed)
Alexander von Kluck — Commanded the First Army and turned inside Paris, exposing his flank. (The Schlieffen Plan and why it failed)
Joseph Joffre — French commander who kept his nerve through the retreat and counter-attacked at the Marne. (The Schlieffen Plan and why it failed)
Richard Hentsch — Staff officer sent forward with authority to order the withdrawal on 9 September. (The Schlieffen Plan and why it failed)
Fritz Haber — Directed the German gas programme; the chemistry that fixed nitrogen for fertiliser also supplied explosives and gas. (Trenches, new weapons and the reasons for deadlock)
Ernest Swinton — Among those who pressed for the tank's development in 1915. (Trenches, new weapons and the reasons for deadlock)
Julian Byng — Commanded at Cambrai, where massed tanks and predicted artillery fire were combined. (Trenches, new weapons and the reasons for deadlock)
Douglas Haig — Commander-in-Chief of the BEF from December 1915 through the Somme, Passchendaele and the Hundred Days. (The Somme, Passchendaele and the responsibility of Haig)
Henry Rawlinson — Commanded Fourth Army on the Somme and favoured limited bite-and-hold objectives against Haig's wider aims. (The Somme, Passchendaele and the responsibility of Haig)
David Lloyd George — Prime Minister from December 1916; withheld reinforcements in early 1918 and wrote the memoirs that shaped Haig's reputation. (The Somme, Passchendaele and the responsibility of Haig)
Erich Ludendorff — Recorded the German army as fought to a standstill by the end of 1916. (The Somme, Passchendaele and the responsibility of Haig)

What students say — and what is actually the case

“The plan failed because of brave Belgian resistance.” — Liège cost around eleven days, which was serious and not decisive. Russia's speed, the logistics of a 500-kilometre march and the turn inside Paris did more, and a good answer ranks them rather than choosing the most flattering. (The Schlieffen Plan and why it failed)
“Soldiers spent years continuously in the front-line trench.” — Battalions rotated through front line, support, reserve and rest. The experience was long periods of labour and boredom punctuated by intense danger, and shellfire killed more men than assaults did. (Trenches, new weapons and the reasons for deadlock)
“The Somme achieved nothing.” — It relieved Verdun, inflicted losses the German command recorded as unsustainable, and was where the British army learned. It also cost 420,000 casualties for six miles. Both belong in the answer and the criterion decides which weighs more. (The Somme, Passchendaele and the responsibility of Haig)

What the specification asks for

The clauses of 4HI1 this key topic examines, one per lesson. Incandio is aligned to the specification and is not published by Pearson.

“The Schlieffen Plan and reasons for its failure” — The Schlieffen Plan and why it failed
“The trench system, life in the trenches, new weapons and methods. Reasons for deadlock.” — Trenches, new weapons and the reasons for deadlock
“Key features of Somme and Passchendaele. Successes and failures on the Western Front, including the responsibility of Haig.” — The Somme, Passchendaele and the responsibility of Haig

Then teach it, and defend it

Every lesson above ends the same way: you explain the argument to Ember, an AI pupil who asks the awkward question, and defend it in a structured debate marked against published descriptors.

All of The origins and course of the First World War, 1905–18 · Incandio History · The 4HI1 specification