Russia: Plans G, A and 19

Russia, meanwhile, put together two very different plans for war.  Plan G assumed that Germany would launch the war with a full-scale attack against Russia; the opposite of what actually transpired.  Unusually, Plan G was content to permit German infringement of Russia's borders, with the consequent loss of territory and large-scale casualties, pending completion of Russian army mobilization.

In short, the Russian military assumed that the country could readily bear a string of defeats at the start of the war; such was the reserve of manpower ultimately available to the army.  Once effectively mobilized, they believed that the Russian army would inevitably eject Germany from within its borders.  Napoleon had failed to conquer the vastness of Russia; it was assumed that Germany would likewise fail.

Plan 19 - also known as Plan A - was less drastic in its initial sacrifice of Russian manpower.  Russia's French partners pressed the Russian military to devise a more offensive war strategy.

Plan 19, devised in 1910 by General Danilov and substantially modified in 1912, and correctly assumed that Germany would open the war with an attack against France rather than Russia.

This being the case, two Russian armies would advance into East Prussia and to Silesia en route to central Germany.  Russia would at the same time make use of a fortress defense against invading forces.

In the event, the Russian advance into East Prussia was thrown back almost immediately upon the start of the war, with the Russian army suffering a particularly crushing defeat at Tannenberg, followed by lesser setbacks at the First and Second Battles of the Masurian Lakes.

Belgium

Belgium, by its very neutrality, could not openly plan for war.  Instead, upon the declaration of war (or, in the case of Germany, invasion), the entirety of Belgium's armed forces, comprising 117,000 field troops, were concentrated west of the River Meuse in the (ultimately unsuccessful) defense of Antwerp.

Some 67,000 additional fortress troops were responsible for the defense of the forts at Liege, Namur and Antwerp.

Serbia

The Serbian plan for war was simple: upon declaration of war the army would be doubled from five to ten divisions and placed in readiness to strike against Austria-Hungary once it became apparent what the latter's tactical intentions were.

Britain

The British did not devise a general war strategy in the same sense as France, Germany, Austria-Hungary and Russia.  Unlike these powers, Britain had no particular desire for war to break out, and had no plans for expansion, although she was keen to protect her interests, in particular her trading links with her far-flung empire.

However once war broke out Britain, governed by Asquith's administration, and after some initial confused dithering, determined to come to the aid of 'Brave Little Belgium' (as Belgium was represented in the initial British propaganda recruitment campaign) and to France.

In the absence of a conscripted army, the British Expeditionary Force (or BEF) was to be transported to the continent and onwards by rail to Belgium and the French left flank.  It was estimated that it would take three full weeks, 21 days, to mobilize the BEF; Germany and France banked upon mobilizing within 15 days.