The Battle of the Masurian Lakes ends today near the place where the disastrous Russian offensive opened near Stallupönen 24 days ago. Having annihilated one of the two Russian armies attacking East Prussia, the Imperial German Army has now finished soundly defeating the second, losing just ten thousand men to inflict 125,000 casualties on General Rennenkampf. The Russian 10th Army arrives to support his flank near Sredniki, a town close to the Neman River that divides the prewar empires. After a brief engagement today, the Germans fall back to hold a defensive line at their borders.

Germany did not know that Russia kept three-fifths of her peacetime army in Poland, but they have more than made up for this intelligence failure. General Ludendorff’s Eighth Army has been supplemented by troops drawn away from the war in the west, where the Kaiser’s General Staff expected to knock France out of the war quickly. These mobilization changes have helped gaps open up in the German lines, precipitating a retreat in good order to the Aisne River.

Today, British troops encounter German defenders in deeply-dug trenches along the riverbank and the ridge line behind it. Rather than attack, Sir John French orders his own troops to fall back and dig in themselves. His French allies, who have been encountering and attacking entrenched Germans for two days, sneer at their ally’s cowardice and continue to push forward into a meat-grinder.

Russian mobilization is proving just as slow as German intelligence expected it to be. Rails and roads are insufficient to send more than a narrow stream of soldiers to the front, and detailed Russian timetables have already given way to the realities of battle. Trainloads of reinforcements must often sit still on sidetracks to let open-topped trains full of wounded soldiers go in the opposite direction. Most roads are not hardened pavement, but dirt that transforms to mud whenever it rains.

And it is a wet September.

The Eastern Front has its periods of entrenched stalemate, but never in a continuous line from mountain to sea. The war is different here because there are still great, sweeping movements that deliver grand strokes and decisive blows, whereas the Western Front is rapidly solidifying into a single, stubborn, man-killing mess. As much as we now see the trenches that way, it is worth pointing out that casualties are actually higher here on this front, where much of the war happens without trenches and the war more often resembles the battles of centuries past, but on a larger scale.

Germany and Russia use different railroad track gauges, which means that neither army can use their own rolling stock while invading the other. Furthermore, captured locomotives and cars can only be used on captured tracks. This has been a deliberate policy choice of the Tsar: Russian defensive doctrine has always traded space for time as they did a century ago against Napoleon.

The experience informs German preparations for a second war. When Hitler’s panzers drive east in 1941, pioneer battalions are ready and equipped to rapidly lay down mile after mile of narrow-gauge track on the Russian crossties, enabling offensives at a scale that the Kaiser’s generals could only dream of orchestrating.

Both fronts have seen aircraft begin to make a difference to actions on the ground. Cities are already being bombed; an unknown German Taube pilot has been making evening raids on Paris to drop improvised aerial bombs that do little damage, but do cause quite a stir. Pilots on the Western Front spotted a big gap in the German lines during the Battle of the Marne a week ago, though the British Expeditionary Force (BEF) failed to exploit it.

And those daring men in their flying machines have also started dying.

In the last week, pilots on all fronts have also begun shooting at each other with pistols — and even throwing grenades, if we are to believe the anecdotes. Witnesses are in short supply at first because there are no wingmen yet. In fact, the whole business of air combat is so new that five days ago, Russian pilot Pyotr Nesterov attempted to bring down an Austrian plane by ramming it with his landing gear, killing himself and both enemy aviators because none of them were strapped into their cockpits as both planes spun upon impact.

Today, French and German pilots are already having hostile encounters over the Aisne; soon, pilots will be flying the first dedicated air combat patrols.

Germany has organized her entire war plan around a quick victory that would prevent them from being forced to fight on two fronts simultaneously. This is the moment when a quick victory might have been achieved, but instead the Western Front is reaching stalemate — while on the Eastern Front, Russia still has enormous armies en route to challenge the Kaiser’s troops. Rather than resolve the conflict, airplanes and roads and rails prolong it.