Finland participated in the Second World War initially in a defensive war against the Soviet Union, followed by another, this time offensive, war against the Soviet Union acting in concert with Nazi Germany, and then finally fighting alongside the Allies against Germany.
The first two major conflicts in which Finland was directly involved were the defensive Winter War against an invasion by the Soviet Union in 1939, followed by the offensive Continuation War, together with Germany and the other Axis powers against the Soviets, in 1941–1944. The third conflict, the Lapland War against Germany in 1944–1945, followed the signing of the Moscow Armistice with the Allied Powers, which stipulated the expulsion of Nazi German forces from Finnish territory.
The Soviet attempt to conquer Finland in the Winter War was thwarted, and by the end of World War II, Finland remained an independent country. Finland ceded approximately 10% of its territory to the Soviet Union, including Viipuri (Finland's second-largest city [Population Register] or fourth-largest city [Church and Civil Register], depending on the census dataStatistics Finland (1940)). Finland was also required to pay out a large amount of war reparations to the Soviet Union and to formally acknowledge partial responsibility for the Continuation War. Finnish political policy during the Cold War aimed to appease the Soviet Union to maintain good relations.
Background Finnish independence
In 1809, the Russian Empire seized Finland from Sweden in the Finnish War. Finland entered a personal union with the Russian Empire as a grand duchy with extensive autonomy.
On 6 December 1917, during the Russian Civil War, the Finnish parliament (Suomen Eduskunta) declared independence from Russia, a declaration that was accepted by the Bolshevik government of the Soviet Union on 31 December. In January 1918, the Eduskunta ordered General Gustaf Mannerheim to use local Finnish White Guards to disarm Finnish Red Guards and Russian troops throughout the country, a process which began on 27 January and led to the beginning of the Finnish Civil War.
After the Eastern Front and the collapse of peace negotiations between the Bolsheviks and Germany, German troops intervened in Finland, occupying Helsinki and other parts of the country. The Red faction was defeated, and the survivors were subjected to a reign of terror, in which at least 12,000 people died. A new government, with Juho Kusti Paasikivi as prime minister, pursued a pro-German policy and sought to annex Russian Karelia, which had a Finnish-speaking majority, despite never having been a part of Finland.
Treaty of Tartu: 1920
After the extinction of the Hohenzollern monarchy on 9 November 1918, Poland, Estonia, Latvia, and Lithuania became independent, German troops left Finland, and British ships patrolled the Baltic Sea. Mannerheim was elected regent by the Eduskunta, and Finnish policy became pro-Entente as the western powers intervened in the Russian Civil War (7 November 1917 – 16 June 1923). Mannerheim favoured intervention against the Bolsheviks, but suspicion of the White Russians who refused to recognise Finnish independence led to his aggressive policy being overruled; then, the Bolshevik victory in Russia forestalled Finnish hostilities.
Paasikivi led a delegation to Tartu, in Estonia, with instructions to establish a frontier from Lake Ladoga in the south, via Lake Onega to the White Sea in the north. The importance of the Murmansk railway, built in 1916, led the Soviet delegation to reject the Finnish border proposal, and the treaty of 14 October 1920 recognised a border agreement in which Finland obtained the northern port of Petsamo (Pechenga), an outlet to the Arctic Ocean, and a border roughly the same as that of the former Grand Duchy of Finland. Claims on areas of Eastern Karelia were abandoned, and the Soviets accepted that the south-eastern border would not be moved west of Petrograd.
Winter War
During the Interwar period, relations between Finland and the Soviet Union were tense. Some elements in Finland maintained the dream of a "Greater Finland" which included the Soviet-controlled part of Karelia, while the proximity of the Finnish border to Leningrad (now Saint Petersburg) caused worry among the Soviet leadership. On 23 August 1939, Nazi Germany and the Soviet Union signed the Molotov–Ribbentrop Pact, which included a secret clause demarcating Finland as part of the Soviet sphere of influence.
On 12 October, the Soviet Union began negotiations with Finland regarding the disposition of the Karelian Isthmus, the Hanko Peninsula, and various islands in the Gulf of Finland, all of which the Finns considered Finnish territory. No agreement was reached. On 26 November, the Soviet Union accused the Finnish army of shelling the village of Mainila. Later research indicates that the Soviets had, in fact, shelled their own village in order to create a pretext for withdrawal from their non-aggression pact with Finland.Murphy (2021), p. 9 On 30 November 1939, the Soviet Union attacked Finland. The attack was denounced by the League of Nations, and as a result, the Soviet Union was expelled from that body on 14 December.
The aim of the invasion was to liberate the 'Red Finns' and eventually annex Finland to the Soviet Union. To this end, a puppet government, the Finnish Democratic Republic, was established in Terijoki under the leadership of the exiled O. W. Kuusinen. Strategic goals of the Red Army included cutting Finland in half and capturing Petsamo in the north and Helsinki in the south.
The leader of the Leningrad Military District, Andrei Zhdanov, commissioned a celebratory piece from Dmitri Shostakovich, Suite on Finnish Themes, intended to be performed as the marching bands of the Red Army paraded through Helsinki.
The Soviets had been building up their forces on the border during the earlier negotiations and now fielded four armies comprising 16 divisions, with another three being brought into position; meanwhile, the Finnish army had just 9 smaller divisions. The Soviets also enjoyed overwhelming superiority in the number of armour and air units deployed. The Finns had to defend a border that was some 1287 km (800 miles) in length, putting them at a significant disadvantage.
First offensive November 1939 The Winter War was fought in two Soviet offensives, divided by a short lull. The war was fought mainly in three areas. The Karelian Isthmus and the area of Lake Ladoga were the primary focus of the Soviet war effort. A two-pronged attack was launched in this region, with one pincer engaging Finnish forces on the Isthmus while the other went around Lake Ladoga to encircle the defenders. This force was then to advance to and capture the city of Viipuri. The second front was in central Karelia, where Soviet forces were to advance to the city of Oulu, cutting the country in half. Finally, a drive from the north was intended to capture the Petsamo region.
The first attack, on 30 November 1939, was an aerial bombardment of Helsinki, with subsidiary attacks along the Finnish-Soviet border. This had the effect of instantly unifying the once deeply-divided Finnish people in defense of their homes and country, without any referendums needing to be held.Jakobson, p.157
By late December, the Soviets had become bogged down, with the two main fronts at a standstill as the Finns counterattacked with greater strength than anticipated. With two of its three offensives having failed by the end of December, Soviet headquarters ordered a cessation of operations. By 27 December, it was observed that the Soviets were digging in on the Karelian Isthmus. In the north, the Finns had been pushed back to Nautsi, but with reinforcements, had been able to take the higher ground and halt the Soviet advance south of Petsamo. During this period, the Finns harassed supply columns and carried out raids against fortified Soviet positions.
A lull followed in January 1940, as the Soviet army reassessed its strategy and rearmed and resupplied. On 29 January, Molotov put an end to the puppet Terijoki Government and recognized the Ryti government as the legal government of Finland, informing it that the USSR was willing to negotiate peace.Trotter (2002), pp. 234–235Enkenberg, p.215
Second Offensive February 1940 The last phase began in February 1940, with a major artillery barrage that began on the 2nd and lasted until the 11th, accompanied by reconnaissance raids at key objectives. The Soviets, using new equipment and materials, also began using the tactic of rotating troops from the reserve to the front, thus keeping constant pressure on the Finnish defenders. Relative to Finnish resources, the Red Army seemed to have inexhaustible amounts of ammunition and supplies, as attacks were always preceded by barrages, followed by aerial assaults and then random troop movements against the lines. Finnish military and government leaders came to feel that their only hope of preserving their nation lay in negotiating a peace treaty with Moscow.
The tenacity of the Finnish people, both military and civilian, in the face of a superior opponent gained the country much sympathy throughout the world; however, material support from other countries was very limited, as none of Finland's neighbors were willing to commit their militaries to a war against the USSR.
The need for a diplomatic solution became even more apparent after Soviet forces broke through the Finnish defensive line on the Karelian Isthmus and moved on towards Viipuri.Jakobson, p.239
A peace proposal authored by Molotov was sent to Helsinki in mid-February. It placed heavy demands on Finland, including claims to more land for the USSR and the imposition of significant diplomatic and military sanctions. By 28 February, Molotov had turned his offer into an ultimatum with a 48-hour deadline, which pushed the Finnish leadership to act quickly.Jakobson, p.238 On 12 March 1940, the Moscow Peace Treaty was signed, with hostilities ending the following day. By the terms of the treaty, Finland ceded 9% of its territory to the USSR. This was more territory than the Soviets had originally demanded.Upton, Anthony F. Finland in Crisis 1940–1941: A Study in Small-Power Politics. Ithaca, NY, Cornell University Press, 1965, p. 35
Interim peace
The period of peace following the Winter War was widely regarded in Finland as temporary, even when peace was announced in March 1940. A period of frantic diplomatic efforts and rearmament followed. The Soviet Union maintained intense pressure on Finland, thereby hastening Finland's efforts to improve the country's security.
Defensive arrangements were attempted with Sweden and the United Kingdom, but the political and military situation during the Second World War rendered these efforts fruitless. Finland then turned to Nazi Germany for military aid. As the German offensive against the Soviet Union (Operation Barbarossa) approached, the cooperation between the two countries intensified. German troops arrived in Finland and took up positions, mostly in Lapland, from where they would invade the Soviet Union.
Continuation War