The Hoffmann Plan was a German military plan published by German Minister of War Hans von Hoffmann (as well as Admiral Alfred von Tirpitz and General Paul von Hindenburg) in late 1908 stating that, in the event of war with the Russian Empire, the High Seas Fleet's destruction of the Russian Baltic Fleet to occur before an amphibious invasion of southern Finland. The landing of soldiers in Finland - and, in particular, the city of Helsinki - would come as a distraction to Russian commanders and force them to divert troops from the front lines in Congress Poland northward to contain the German amphibious invasion.
The decision to land troops at Helsinki following the defeat of the Baltic Fleet came following the Helsinki Massacres, to which Kaiser Wilhelm II wished to use to his advantage to further Germany's position in Europe's political scene.
The demands to destroy the Baltic Fleet came from the argument that the German force landing at Helsinki had to be strong enough to deter any Russian counterattacks (to this, several German generals suggested a force of at least 60,000, which was to grow to some 100,000 over time during the actual invasion) and the Baltic Fleet posed a massive threat to the supply lines of marines in Finland. The plan called for, if the total destruction of the Russian ships proved impossible, "... a blockade of these ships to their respective ports, and in effect neutralizing all effectiveness of these ships, including, but not limited to, their ability to harm German merchant shipping and ... to deter the effectiveness of military units operating within the Baltic Sea, and any land forces operating within or outside of established German territory."
The Hoffmann Plan was, in part, fulfilled during the Baltic War following the Battle of the Gulf of Finland, in which the Russian fleet was so severely weakened it was relegated to its port for the remainder of the war, allowing the High Seas Fleet free reign over the Baltic Sea.