Also known as the Winter Battle of the Masurian Lakes - because it opened during a severe blizzard - the Second Battle of the Masurian Lakes formed part of Paul von Hindenburg's plan for a two-pronged decisive push against Russia by the Austro-Germans, the aim being to force Russia's defeat and so bring about an end to war on the Eastern Front.
Specifically, Hindenburg intended to outflank Russian positions in central Poland, pushing them back beyond the Vistula River.
Hindenburg's plan called for the deployment of two armies in East Prussia - the Eighth and Tenth - set against the Russia Tenth Army, commanded by General Sievers. Siever's army consisted of four corps, positioned north of the Masurian Lakes. This comprised the northern prong of Hindenburg's push against the Russians. The German armies would advance north and south of the fortified Angerapp Line running through the Masurian Lakes.
The plan was sanctioned by German Chief of Staff Erich Falkenhayn despite his reluctance to commit resources in the east - he firmly believed the war was to be won in the west. Falkenhayn agreed to the offensive after deciding that it would present a favourable impression upon potential allies in the Balkans if large-scale action were taken against Russia.