Confusion among the Central Powers.
The strategy of the Central Powers suffered from miscommunication. Germany had promised to support Austria-Hungary's invasion of Serbia, but interpretations of what this meant differed. Previously tested deployment plans had been replaced early in 1914, but the replacements had never been tested in exercises. Austro-Hungarian leaders believed Germany would cover its northern flank against Russia. Germany, however, envisioned Austria-Hungary directing most of its troops against Russia, while Germany dealt with France. This confusion forced the Austro-Hungarian Army to divide its forces between the Russian and Serbian fronts.
On 9 September 1914, the Septemberprogramm, a possible plan that detailed Germany's specific war aims and the conditions that Germany sought to force on the Allied Powers, was outlined by the German Chancellor, Theobald von Bethmann-Hollweg. It was never officially adopted.
Austria invaded and fought the Serbian army at the Battle of Cer and Battle of Kolubara beginning on 12 August. Over the next two weeks, Austrian attacks were thrown back with heavy losses, which marked the first major Allied victories of the war and dashed Austro-Hungarian hopes of a swift victory. As a result, Austria had to keep sizable forces on the Serbian front, weakening its efforts against Russia. Serbia's defeat of the Austro-Hungarian invasion of 1914 counts among the major upset victories of the last century
This campaign had the youngest known soldier of World War I. Momčilo Gavrić, born in Trbušnica, joined the 6th Artillery Division of the Serbian Army when he was 8 years old, after Austro-Hungarian troops killed his parents, grandmother, and seven of his siblings in August 1914. At the age of 10 he was promoted to Corporal, and at the age of 11 he became a Lance Sergeant.
German forces in Belgium and France.
At the outbreak of World War I, the German army (consisting in the West of seven field armies) carried out a modified version of the Schlieffen Plan. This marched German armies through neutral Belgium and into France, before turning southwards to encircle the French army on the German border. Since France had declared that it would "keep full freedom of acting in case of a war between Germany and Russia", Germany had to expect the possibility of an attack by France on one front and by Russia on the other. To meet such a scenario, the Schlieffen Plan stated that Germany must try to defeat France quickly (as had happened in the Franco-Prussian War of 1870–71). It further suggested that to repeat a fast victory in the west, Germany should not attack through the difficult terrain of Alsace-Lorraine (which had a direct border west of the river Rhine), instead, the idea was to try to quickly cut Paris off from the English Channel and British assistance, and take Paris, thus winning the war. Then the armies would be moved over to the east to meet Russia. Russia was believed to need a long period of mobilisation before they could become a real threat to the Central Powers.
The only existing German plan for any war had German armies marching through Belgium. Germany wanted free escort through Belgium (and originally the Netherlands as well, which plan Kaiser Wilhelm II rejected) to invade France. Neutral Belgium rejected this idea, so the Germans decided to invade through Belgium instead. France also wanted to move their troops into Belgium, but Belgium originally rejected this "suggestion" as well, in the hope of avoiding any war on Belgian soil. In the end, after the German invasion, Belgium did try to join their army with the French, but a large part of the Belgian army retreated to Antwerp where they were forced to surrender when all hope of help was gone.
The plan called for the right flank of the German advance to bypass the French armies (which were concentrated on the Franco-German border, leaving the Belgian border without significant French forces) and move south to Paris. Initially the Germans were successful, particularly in the Battle of the Frontiers (14–24 August). By 12 September, the French, with assistance from the British forces, halted the German advance east of Paris at the First Battle of the Marne (5–12 September), and pushed the German forces back some 50 km (31 mi). The last days of this battle signified the end of mobile warfare in the west. The French offensive into Southern Alsace, launched on 20 August with the Battle of Mulhouse, had limited success.
In the east, the Russians invaded with two armies, surprising the German staff who had not expected the Russians to move so early. A field army, the 8th, was rapidly moved from its previous role as reserve for the invasion of France, to East Prussia by rail across the German Empire. This army, led by general Paul von Hindenburg defeated Russia in a series of battles collectively known as the First Battle of Tannenberg (17 August – 2 September). But the failed Russian invasion, causing the fresh German troops to move to the east, allowed the tactical Allied victory at the First Battle of the Marne. The Central Powers were denied a quick victory in France and forced to fight a war on two fronts. The German army had fought its way into a good defensive position inside France and had permanently incapacitated 230,000 more French and British troops than it had lost itself. Despite this, communications problems and questionable command decisions cost Germany the chance of early victory.
Asia and Pasific in World War 1.
New Zealand occupied German Samoa (later Western Samoa) on 30 August 1914. On 11 September, the Australian Naval and Military Expeditionary Force landed on the island of Neu Pommern (later New Britain), which formed part of German New Guinea. On 28 October, the German cruiser SMS Emden sank the Russian cruiser Zhemchug in the Battle of Penang. Japan seized Germany's Micronesian colonies and, after the Siege of Tsingtao, the German coaling port of Qingdao in the Chinese Shandong peninsula. As Vienna refused to withdraw the Austro-Hungarian cruiser SMS Kaiserin Elisabeth from Tsingtao, Japan declared war not only on Germany, but also on Austria-Hungary; the ship participated in the defense of Tsingtao where it was sunk in November 1914. Within a few months, the Allied forces had seized all the German territories in the Pacific; only isolated commerce raiders and a few holdouts in New Guinea remained.
Some of the first clashes of the war involved British, French, and German colonial forces in Africa. On 6–7 August, French and British troops invaded the German protectorate of Togoland and Kamerun. On 10 August, German forces in South-West Africa attacked South Africa; sporadic and fierce fighting continued for the rest of the war. The German colonial forces in German East Africa, led by Colonel Paul von Lettow-Vorbeck, fought a guerrilla warfare campaign during World War I and only surrendered two weeks after the armistice took effect in Europe.
Indian support for the Allies.
Contrary to British fears of a revolt in India, the outbreak of the war saw an unprecedented outpouring of loyalty and goodwill towards Britain. Indian political leaders from the Indian National Congress and other groups were eager to support the British war effort, since they believed that strong support for the war effort would further the cause of Indian Home Rule. The Indian Army in fact outnumbered the British Army at the beginning of the war; about 1.3 million Indian soldiers and labourers served in Europe, Africa, and the Middle East, while both the central government and the princely states sent large supplies of food, money, and ammunition. In all, 140,000 men served on the Western Front and nearly 700,000 in the Middle East. Casualties of Indian soldiers totalled 47,746 killed and 65,126 wounded during World War I. The suffering engendered by the war, as well as the failure of the British government to grant self-government to India after the end of hostilities, bred disillusionment and fuelled the campaign for full independence that would be led by Mohandas Karamchand Gandhi and others.