|Battle of Stallupönen|
|Part of Invasion of East Prussia, Eastern Front of World War I|
|Commanders and leaders|
|Mikhail Alekseyev||Hermann von François|
|Elements of the First Army||Elements of the Eighth Army|
|Casualties and losses|
|2,591 killed or wounded||8,672 killed or wounded|
The Battle of Stallupönen, fought between Russian and German armies on August 17, 1914, was the opening battle of World War I on the Eastern Front. With more than fivefold numerical superiority (84,000 Russians against 16,000 Germans), the Russian army was triumphant. It was a minor Russian success, but did little to upset the German planning.
The German Schlieffen Plan was based on defeating France (and the United Kingdom, should it be involved) as quickly as possible in the west, which would then permit the Germans to transport their forces eastward to meet the massive Russian Army. The Russians were able to field up to ten complete armies compared to Germany's eight, but they were scattered across the country and would take some time to organize and move up. This meant that the Germans had a short window of time where they could fight a defensive battle, holding off what forces the Russians could move forward, while they waited for the battles in the west to be decided.
Immediately prior to the opening of hostilities, the Eastern Front developed largely according to pre-war planning. Two Russian armies were in the immediate area, Mikhail Alekseyev's First Army east of the city of Königsberg, and Alexander Samsonov's Second Army to the south. Alekseyev planned on marching on Königsberg, then head south towards Samsonov, and attack the main German positions concentrated to the south.
The Germans were also deployed largely according to everyone's expectations. The German Eighth Army was strung out in pockets in front of Alekseyev, but did not have the manpower to completely cover the front of either of the Russian armies. On paper, the situation looked almost hopeless, and the standing orders were to fight a delaying retreat. However, Hermann von François, the commander of the First Corps of the German Eighth Army, was convinced his better-trained and equipped forces could halt, and perhaps defeat, Alekseyev's Russian forces.
Most of the Eighth Army was organized into a defensive line running south of Gumbinnen, about 20 miles (32 km) west of the Russian border. However, small units were sent forward to garrison towns, railway lines and strongpoints. They were ordered to retreat on contact with the enemy, joining the main forces at Gumbinnen. For the first five days of the war, the only combat was minor skirmishes with Alekseyev's cavalry who were conducting reconnaissance along the border area.