At the beginning of the war all but the last were absolutely known quantities, and as far as Russia and Germany were concerned this last factor could be figured out comparatively easily. For it was clear that if Germany would become involved in a war with Russia, Austria would be found fighting by its ally's side and vice versa. It was also fairly reasonable to assume, and had immediately become a fact, that under such conditions Germany would find itself involved with France too, which would mean that Germany's available fighting strength would have to be divided into two parts at least. It was, of course, a matter of fairly common knowledge that Germany's concentration was much more powerful on its western border than on its eastern, so that Russia could count with reasonable certainty on a comparative weak, even if well organized, resistance on the part of Germany at the beginning of war.
Germany's strategy in the east was influenced chiefly by its plan for the western campaign, which we have already considered in the preceding chapters. The fight against France seemed to be of greater importance and urgency to Germany than that against Russia. Why German strategy reached this conclusion does not concern us here. In passing, however, it may be well to remember that the German provinces adjoining France directly, or indirectly behind Belgium and Luxemburg, were of much greater importance and value to the Germans than their provinces adjoining Russia, and that even the temporary loss of these would probably have spelled disaster to Germany. Then, too, it was on the western side that England's influence was being felt; and, furthermore, the French army, though much less numerous than the Russian, was a more formidable adversary on account of its greater effectiveness, as well as of the certainty of its much quicker movements.
Russia had a preponderantly large advantage in numbers over Germany. The result of this fact, from a strategic point of view, was that Russia could dare much more than her adversaries. She could strike stronger, quicker, and with greater frequency in more directions, and could risk to extend her operations much farther. The fact that means of transportation, as has been pointed out, were much better developed in the German frontier provinces than in those of Russia, was a disadvantage only as long as Russia fought on its own territory, though even then, necessarily, the invading enemy would be hampered at least equally by the lack of transportation facilities.
Russia's natural advantage of greater numbers pointed clearly to an immediate offensive which would bring with it the promise of more advantages, while both German and Austrian conditions indicated with equal clearness as the safest and sanest strategy a policy of "watchful waiting," at least until such time when large enough forces could be spared from the western front or concentrated from available reserve sources to promise to a more aggressive policy a fair chance of success.
Thus Russia decided to strike immediately against Germany as well as against Austria. With the latter campaign we are not concerned here. How she devoted herself to this twofold task with all the power and means at her command we shall see in the following narrative.
The hosts of Russia were standing on the German frontier. In the four provinces adjoining Austria-Hungary a total of sixteen army corps, or one-half of all the Russian army in European Russia, were available. By July 31, 1914, the czar had ordered the general mobilization of army and navy. The German Ambassador in Petrograd was instructed to notify the Russian Government that unless this order was countermanded within twelve hours, Germany would immediately respond by mobilization of her army and navy. As the Russian mobilization had continued, Germany officially took the same step in the late afternoon of August 1, 1914, after a state of war had already been proclaimed for the entire empire on July 31, 1914.
The fighting forces on the German side at the beginning of the war on or near the east front included the First Army Corps at Königsberg, the Twentieth at Allenstein, the Seventeenth at Danzig, the Fifth at Posen, and the Sixth at Breslau. These mustered a total of forty-four infantry, twenty-one cavalry, and twenty-five artillery regiments, augmented by four battalions of rifles (Jaeger), and twelve formations of technical troops. The entire peace effectiveness of these formations was about 150,000 men, which at full war strength undoubtedly meant at least not less than 500,000 men, of whom about one-half were of the first line, the balance being made up of reserves and Landwehr troops.
The Russians drew up, in the face of the Germans, two armies: the Army of Poland and the Army of the Niemen. The latter in peace time centered in Vilna and consisted of five army corps; the former used Warsaw as its base and consisted of at least as many army corps. It now held a wide front from the Narev in the north to the valley of the Bug River. These two armies together had an effectiveness of almost twice as many men as the German forces, supported as they were by a series of well-garrisoned fortresses: Grodno, Osowiec, and Bialistock in the north; Lomza, Novo Georgievsk, and Warsaw in the center; and Ivangorod and Brest-Litovsk in the south. In its entirety the mobilization of these forces was completed about the third week of August, 1914, but by the end of the first week the Army of the Niemen had completed its mobilization, and it was from there that the first blow was struck.
This army was commanded by General Rennenkampf, one of the few Russian generals who had succeeded in coming through the Russo-Japanese War, not only with an untarnished, but even with an enhanced reputation. Its task was to invade the northern part of East Prussia, striking directly at Königsberg.
Small engagements, of course, took place all along the Russo-German border between the advance guards of the two armies from the day war had been declared.