Finland and Karelia · Animated schematic fronts

Winter War (Russo-Finnish War)

The Molotov–Ribbentrop Pact of August 1939 assigned Finland to the Soviet sphere of influence. In October Moscow demanded territory on the Karelian Isthmus, islands in the Gulf of Finland and a naval base at Hanko; Finland refused. After the staged border incident at Mainila (26 November) the Red Army attacked on 30 November with more than 450,000 men. The Finnish defence on the Mannerheim Line and the destruction of entire Soviet divisions in the forests (mottis at Suomussalmi, the Raate road and Lemetti) brought the offensive to a halt, but in February 1940 the reinforced 7th Army under Timoshenko broke through at Summa. The Moscow Peace Treaty (12 March 1940) cost Finland Karelia with Viipuri; the Soviet Union counted 126,875 dead by its own return, Finland more than 25,000.

Schematic front line based on standard overview maps of the main phases. Movement between the dated moments is smoothly interpolated and is not a day-by-day reconstruction; the closing edges of the coloured areas are graphic and may include sea or uninvolved land. On the Karelian Isthmus the line follows the border, the Mannerheim Line and the Soviet breakthrough of February 1940; in eastern and northern Finland, where no continuous front existed, it is the schematic limit of the Soviet penetrations, with the encircled divisions (mottis) shown as rings.