[25] According to German intelligence estimates, the railway network in Poland limited the Russians to three options: a purely defensive posture against Germany, an offensive down the Vistula straight towards Berlin or an invasion of East Prussia with two armies, one from the Narew and one from the Neman.

[26] In 1894 Alfred von Schlieffen, then Chief of the German General Staff, war-gamed a scenario that corresponded to the Battle of Tannenberg in 1914.

In the exercise critique Schlieffen said the Germans could easily just establish a defensive line behind the Vistula, but when the opportunity to destroy an entire Russian army was available, it should be taken.

He told the French ambassador that Russia would invade East Prussia quickly to draw Germany's attention away from France.

Grand Duke Nicholas and the high command were optimistic, planning to split Russia's forces between East Prussia in the north and Galicia in the south, securing the Polish salient if they were successful, before then pushing from central Poland towards Berlin.

Although outnumbering the enemy, the Russian Army had numerous problems that contributed to its defeat: Russia was not prepared for a large war at the time as it was in the midst of a rearmament programme,[33][34] as was known to the Germans.

[35] Many soldiers were untrained,[36] its transport service was largely ineffective due to a lack of railways from the Russian side of East Prussia.

This would have fitted in with the plans made before the start of the First World War; that these were the positions the Germans would retreat to if the Russians put up a much stronger fight than they had anticipated.

Short of food and artillery ammunition and incorrectly believing the Germans were in full retreat, Rennenkampf did not pursue, refitted for a couple days, and lost contact.

Under pressure to advance and cut off the supposed German retreat, Samsonov's Second Army outdistanced their supplies resulting in hungry demoralized troops.

Following the plans of Colonel Max Hoffmann, Prittwitz's deputy chief of operations, they chose to wheel eight of their divisions counter-clockwise to attack Samsonov; taking advantage of interior lines and well-practiced ability to move quickly via the rail roads.

The invasion was a ghastly failure for the Russians, a setback which was followed by considerable German advances in the following year, including the capture of the Polish city of Warsaw.

These additional forces did not arrive in time for the twin battles as Ludendorff predicted and, had they entered France as originally planned, could have been tremendously helpful to the precarious situation in the West.

In addition, according to reports from part of the encircled formations, the casualties in the Russian 13th and 15th army corps on October 1 (by this time those who had fallen behind or escaped from the encirclement had practically ceased to return) amounted to 1,552 officers (of which, according to available information, 111 were killed, 143 wounded and 907 were missing or captured, there is no data on the rest, especially for those called up from the reserve) and 76,472 soldiers (of which 3,130 were killed, 2,412 were wounded, 44,646 were missing, there is no data on the rest, especially for those called up from the reserve).

In this case, this is the full composition of all the fighting units, including landstorm battalions serving in headquarters, sappers (pioneers), heavy artillery, medics, signalmen, pilots (15 men) and sailors of the river flotilla (two).

In any case, the combat casualties of the German troops in East Prussia reach 42,630 men, of which 1,303 are officers, which was 6 times less than the damage of the Russian armies operating against them.

The huge masses of the armed forces made the armies little mobile and little capable of decisive maneuvers, which distinguished the wars of the past.

In terms of the elegance of its maneuver, the decisiveness of the goal it achieved, and, finally, the infrequent in military history, the implementation of the complete encirclement of the enemy by forces almost inferior to him, the East Prussian operation of the 8th German army against the 2nd Russian is throughout not only the world war, but, perhaps, wars of the last centuries is a rare example of military art and deserves absolutely exceptional attention.

In this battle, played out on a relatively insignificant front, between two separate armies, which had free flanks, and therefore freedom of maneuver, the strategic art of command was revealed with complete distinctness and is therefore of great instructive interest, the identification of which is the task of any military historical description.

These favorable conditions, in which the Russian armies were located, are of such self-sufficient strategic importance that they are in no way compensated by the more developed network of railways and dirt roads in East Prussia and the more advanced equipment of its theater of operations, which, moreover, should be reckoned not to the position of the opposing armies assessed here, as such, but to the foresight of the Prussian General Staff in peacetime.