Osprey The English Civil War

In the wake of the bloody civil war that followed Finland's independence from Russia in 1917, the border between the two countries was established across the Karelian Isthmus, an area long fought over by Russia, Finland and Sweden in their attempts to dominate the northern tip of Europe. Neither the Soviets nor the Finnish were comfortable with such a divide, which provided an open route for a potential invader to Helsinki on the Finnish side, and was only 32km from the important military and industrial city of Petrograd in Russia. As such, both sides began an intensive period of fortification and defensive planning.