Before World War I Finland was part of Imperial Russia. As part of realm of the Czars, Finland chafed under its rule. After the war Finland, along with Poland, Lithuania, Latvia, and Estonia, were carved out of the old empire and made into autonomous nations.
The founder of the Soviet Union, Vladimir Lenin, was too concerned with issues at home to reclaim the territories. His successor felt it was time. In October 1939 Finland’s emissaries were summoned to Moscow. Stalin gave Finland an ultimatum: move your border so Leningrad was not within artillery range, demilitarize the Karelian Isthmus, cede islands, and allow ports to be leased indefinitely. The Finns were willing to concede on these points; however, the Soviets also wanted basing rights for aircraft and warships in the port of Hango. The Finns demurred; the Soviets broke off negotiations on November 13, 1939. The Finns mobilized, and the Soviets attacked all along the border on November 30. Helsinki was bombed.
At first glance, it seemed the Finns were outmatched. But their small army of 200,000, facing overwhelming Soviet numbers, invented the “Molotov Cocktail” — gasoline in glass jars —to stop Red Army tanks. Stalin’s purges of his forces also began to take their toll. The Red Army failed to be inventive or highly mobile. Timid not because of cowardice, but because of a fear of their own government, the army also had large numbers of unmotivated conscripts. Winter equipment was not available to the Red Army and they froze in the forests, wary of attack from any direction. Stalin was stunned by the mounting losses of his army.