The Winter War was a war between the Soviet Union and Finland. It began with a Soviet invasion of Finland on 30 November 1939, three months after the outbreak of World War II, and ended three and a half months later with the Moscow Peace Treaty on 13 March 1940. Despite superior military strength, especially in tanks and aircraft, the Soviet Union suffered severe losses and initially made little headway. The League of Nations deemed the attack illegal and expelled the Soviet Union from its organization. The Soviets made several demands, including that Finland cede substantial border territories in exchange for land elsewhere, claiming security reasons — primarily the protection of Leningrad, 32 km (20 mi) from the Finnish border. When Finland refused, the Soviets invaded. Most sources conclude that the Soviet Union had intended to conquer all of Finland, and cite the establishment of the puppet Finnish Communist government and the Molotov–Ribbentrop Pact's secret protocols as evidence of this, while other sources argue against the idea of a full Soviet conquest. Finland repelled Soviet attacks for more than two months and inflicted substantial losses on the invaders in temperatures as low as −43 °C (−45 °F). The battles focused mainly on Taipale along the Karelian Isthmus, on Kollaa in Ladoga Karelia and on Raate Road in Kainuu, but there were also battles in Lapland and North Karelia. Following the initial setbacks, the Soviets reduced their strategic objectives and put an end to the puppet Finnish communist government in late January 1940, and informed the legitimate Finnish government that they were willing to negotiate peace. After the Soviet military reorganized and adopted different tactics, they renewed their offensive in February 1940 and overcame the Finnish defences on the Karelian Isthmus. This left the Finnish Army in the main theatre of war near the breaking point, with a retreat seeming inevitable. Consequently, Finnish commander-in-chief Carl Gustaf Emil Mannerheim urged a peace deal with the Soviets, while the Finns still retained bargaining power. Hostilities ceased in March 1940 with the signing of the Moscow Peace Treaty in which Finland ceded 9% of its territory to the Soviet Union. Soviet losses were heavy, and the country's international reputation suffered. Their gains exceeded their pre-war demands, and the Soviets received substantial territories along Lake Ladoga and further north. Finland retained its sovereignty and enhanced its international reputation. The poor performance of the Red Army encouraged German Chancellor Adolf Hitler to believe that an attack on the Soviet Union would be successful and confirmed negative Western opinions of the Soviet military. After 15 months of Interim Peace, in June 1941, Germany commenced Operation Barbarossa, and the Continuation War between Finland and the Soviets began.
Background
Finnish-Soviet relations and politics
Until the early 19th century, Finland was the eastern part of the Kingdom of Sweden. From 21 February 1808 to 17 September 1809, the Russian Empire waged the Finnish War against the Kingdom of Sweden, ostensibly to protect the Russian capital, Saint Petersburg. Eventually Russia conquered and annexed Finland, and converted it into an autonomous buffer state. The resulting Grand Duchy of Finland enjoyed wide autonomy within Russia until the end of the 19th century, when Russia began attempts to assimilate Finland as part of a general policy to strengthen the central government and unify the Empire by Russification. Those attempts were aborted because of Russia's internal strife, but they ruined Russia's relationship with Finland. In addition, support increased in Finland for self-determination movements. World War I led to the collapse of the Russian Empire during the Russian Revolution of 1917 and the Russian Civil War. On 15 November 1917, the Bolshevik Russian government declared that national minorities possessed the right of self-determination, including the right to secede and form a separate state, which gave Finland a window of opportunity. On 6 December 1917, the Senate of Finland declared the nation's independence. Soviet Russia, later the Soviet Union, recognised the new Finnish government just three weeks after the declaration. Finland achieved full sovereignty in May 1918 after a four-month civil war in which the conservative Whites defeated the socialist Reds with the help of the Imperial German Army, pro-German Jägers, and some Swedish troops, in addition to the expulsion of Bolshevik troops. Finland joined the League of Nations in 1920 and sought security guarantees, but Finland's primary goal was co-operation with the Scandinavian countries (mainly Sweden), and focused on the exchange of information and on defence planning (the joint defence of Åland, for example), rather than on military exercises or on the stockpiling and deployment of materiel. Nevertheless, Sweden carefully avoided committing itself to Finnish foreign policy. Finland's military policy included clandestine defence co-operation with Estonia. The period after the Finnish Civil War to the early 1930s was a politically unstable time in Finland because of the continued rivalry between the conservatives and the socialists. The Communist Party of Finland was declared illegal in 1931, and the nationalist Lapua Movement organised anticommunist violence, which culminated in a failed coup attempt in 1932. The successor of the Lapua Movement, the Patriotic People's Movement, had a minor presence in national politics and never had more than 14 seats of the 200 in the Finnish Parliament. By the late 1930s, the export-oriented Finnish economy was growing and the nation's extreme political movements had diminished.
After Soviet involvement in the Finnish Civil War in 1918, no formal peace treaty was signed. In 1918 and 1919, Finnish volunteers conducted two unsuccessful military incursions across the Soviet border, the Viena and Aunus expeditions, to annex areas in Karelia that according to the Greater Finland ideology would combine all Baltic Finnic peoples into a single state. In 1920, Finnish communists based in Soviet Russia attempted to assassinate the former Finnish White Guard Commander-in-Chief, Marshal Carl Gustaf Emil Mannerheim. On 14 October 1920, Finland and Soviet Russia signed the Treaty of Tartu, confirming the old border between the autonomous Grand Duchy of Finland and Imperial Russia proper as the new Finnish–Soviet border. Finland also received Petsamo Province, with its ice-free harbour on the Arctic Ocean. Despite the signing of the treaty, relations between the two countries remained strained. The Finnish government allowed volunteers to cross the border to support the East Karelian uprising in Russia in 1921, and Finnish communists in the Soviet Union continued to prepare for revenge and staged a cross-border raid into Finland, the Pork Mutiny, in 1922. In 1932, the Soviet–Finnish Non-Aggression Pact was signed between both countries, and it was reaffirmed for ten years in 1934. Foreign trade in Finland was booming, but less than 1% of it was with the Soviet Union. In 1934, the Soviet Union also joined the League of Nations.
=== Justification === Soviet General Secretary Joseph Stalin regarded it a disappointment that the Soviet Union could not halt the Finnish Revolution. He thought that the pro-Finland movement in Karelia posed a direct threat to Leningrad and that the area and defences of Finland could be used to invade the Soviet Union or restrict fleet movements. Soviet propaganda then painted Finland's leadership as a "vicious and reactionary fascist clique". Field Marshal Mannerheim and Väinö Tanner, the leader of the Finnish Social Democratic Party, were targeted for particular scorn. When Stalin gained absolute power through the Great Purge of 1938, the Soviets changed their foreign policy toward Finland and began to pursue the reconquest of the provinces of Tsarist Russia that had been lost during the chaos of the October Revolution of 1917 and the Russian Civil War almost two decades earlier. Soviet leaders believed that the old empire's extended borders provided territorial security and wanted Leningrad, only 32 km (20 mi) from the Finnish border, to enjoy a similar level of security against the rising power of Nazi Germany.
Negotiations
In April 1938, NKVD agent Boris Yartsev contacted Finnish Foreign Minister Rudolf Holsti and Finnish Prime Minister Aimo Cajander, stating that the Soviets did not trust Germany and that war was considered possible between the two countries. The Red Army would not wait passively behind the border but would rather "advance to meet the enemy". Finnish representatives assured Yartsev that Finland was committed to a policy of neutrality and that the country would resist any armed incursion. Yartsev suggested that Finland cede or lease some islands in the Gulf of Finland along the seaward approaches to Leningrad, but Finland refused. Negotiations continued throughout 1938 without results. The Finnish reception of Soviet entreaties was decidedly cool, as the violent collectivisation and purges in Stalin's Soviet Union resulted in a poor opinion of the country. Most of the Finnish communist elite in the Soviet Union had been executed during the Great Purge, further tarnishing the Soviets' image in Finland. Meanwhile, Finland was attempting to negotiate a military co-operation plan with Sweden and hoping to jointly defend Åland. The Soviet Union and Nazi Germany signed the Molotov–Ribbentrop Pact in August 1939. It was publicly a non-aggression treaty, but it included a secret protocol in which Central and Eastern European countries were divided into spheres of influence. Finland fell into the Soviet sphere. On 1 September 1939, Germany began its invasion of Poland, and two days later, the United Kingdom and France declared war on Germany. On 17 September, the Soviet invasion of Poland began. After the fall of Poland, Germany and the Soviet Union exchanged occupied Polish lands to establish a new border in accordance with the provisions of the Molotov-Ribbentrop Pact. Estonia, Latvia and Lithuania were soon forced to accept treaties that allowed the Soviets to establish military bases on their soil. Estonia accepted the ultimatum by signing the agreement on 28 September. Latvia and Lithuania followed in October. Unlike the three Baltic countries, Finland started a gradual mobilisation under the guise of "additional refresher training". The Soviets had already started intensive mobilisation near the Finnish border in 1938–39. Assault troops thought to be necessary for the invasion did not begin deployment until October 1939. Operational plans made in September called for the invasion to start in November. On 5 October 1939, the Soviets invited a Finnish delegation to Moscow for negotiations. Juho Kusti Paasikivi, the Finnish envoy to Sweden, was sent to Moscow to represent the Finnish government. Furthermore, the negotiations were attended by Stalin in person, signalling the seriousness of the effort. Paasikivi would later recount his surprise over the friendly atmosphere in which the delegation was received, and mentioned the pleasant manners of Stalin towards them.
The meetings began on 12 October, with Molotov's offer of a mutual assistance pact, which the Finns immediately refused. To the Finns' surprise, Molotov dropped the offer and instead proposed an exchange of territory. The offer stipulated that the Finnish-Soviet border on the Karelian Isthmus be moved westward to a point only 30 km (19 mi) east of Viipuri (Russian: Vyborg) and that Finland destroy all existing fortifications on the Karelian Isthmus. Likewise, the delegation demanded the cession of islands in the Gulf of Finland as well as Rybachy Peninsula (Finnish: Kalastajasaarento). The Finns would also have to lease the Hanko Peninsula for 30 years and to permit the Soviets to establish a military base there. In exchange, the Soviet Union would cede Repola and Porajärvi from Eastern Karelia (2120 square miles), an area twice the size as that of the territory demanded from Finland (1000 square miles). The Soviet offer divided the Finnish government: Gustaf Mannerheim had argued for an agreement, being pessimistic of the Finnish prospects in a war against the Soviet Union but the Finnish government was reticent in reaching an agreement out of mistrust for Stalin for fear of repeated follow-up demands, which would have put the future of Finnish sovereignty in danger. There were also those, such as Foreign Minister Eljas Erkko and Prime Minister Aimo Cajander, and the Finnish intelligence in general, who mistook the demands and the Soviet military build-up as a mere bluff on the part of Stalin, and were thus disinclined to reach an agreement. The Finns made two counteroffers that would cede the Terijoki area to the Soviet Union. This would have doubled the distance between Leningrad and the Finnish border, but was far less than the Soviets had demanded. The Finns would also cede the islands in the Gulf of Finland, but they would not agree to lease any territory to the Soviet Union for military purposes. On the next meeting on 23 October, Stalin lessened his demands: a reduction in the amount of land demanded in Karelia; a reduction of the Hanko garrison from 5000 to 4000 men; and reducing the length of lease from 30 years to whatever date the ongoing (second world) war in Europe would end. However, this sudden change, contrary to previous statements that Soviet demands were minimalist and thus unalterable, had surprised the Finnish government, and lead them to believe more concession may be forthcoming. Thus, Paasikivi's idea of reaching some sort of compromise by offering the Soviets the island of Jussarö and the fort of Ino were refused by Helsinki. On 31 October, Molotov publicly announced the Soviet demands to the Supreme Soviet. This surprised the Finns, and lent credibility to Soviet claims that their demands were minimalist and thus unalterable, as it would have been impossible to reduce them without a loss of prestige after having made them public. However, the Soviet offer was eventually rejected with respect to the opinion of the public and Parliament. At the meeting on 9 November, Paasikivi announced to the attending Stalin and Molotov the Finnish refusal to accept even their reduced demands. The Soviets were visibly surprised. Finnish Foreign Minister Väino Tanner later wrote that "the eyes of our opposite numbers opened wide". Stalin had asked "You don't even offer Ino?" This would become the final meeting: the Soviets stopped responding to further Finnish letters and on 13 November, when the Finnish delegation was recalled from Moscow, no Soviet officials came to see them off. The Finns had left under the expectation that the negotiations would continue. Instead, the Soviet Union ramped up its military preparations. The negotiations had failed, as neither side was willing to substantially reduce their demands, nor was either side able to fully trust the other. The Finns were fearful of an encroachment on their sovereignty, while the Soviets were (claiming to be) fearful of a springboard for international enemies in Finland, in close proximity to Leningrad. No promises to the contrary managed to persuade the other. Additionally, both sides had misunderstood the others position: the Finns had assumed that the Soviets had opened up on a maximalist demand, ready to be traded down smaller. The Soviets instead had stressed the minimalist nature of their demands, and were incredulous over Finnish reluctance to agree. Finally, there was also Stalin's unwillingness or inability to accept that any territorial concessions on the part of Finland would have only been possible by a 5/6th majority in the Finnish parliament. He had mocked such a requirement, proposing that they count his and Molotov's votes, too.
Shelling of Mainila and Soviet intentions
On 26 November 1939, an incident was reported near the Soviet village of Mainila, near the border with Finland. A Soviet border guard post had been shelled by an unknown party resulting, according to Soviet reports, in the deaths of four and injuries of nine border guards. Research conducted by several Finnish and Russian historians later concluded that the shelling was a false flag operation since there were no artillery units there, and it was carried out from the Soviet side of the border by an NKVD unit with the purpose of providing the Soviets with a casus belli and a pretext to withdraw from the non-aggression pact. Soviet war games held in March 1938 and 1939 had been based on a scenario in which border incidents taking place at the village of Mainila would spark the war.
Molotov claimed that the incident was a Finnish artillery attack. He demanded that Finland apologise for the incident and to move its forces beyond a line 20–25 km (12–16 mi) from the border. Finland denied responsibility for the attack, rejected the demands and called for a joint Finnish–Soviet commission to examine the incident. In turn, the Soviet Union claimed that the Finnish response was hostile, renounced the non-aggression pact and severed diplomatic relations with Finland on 28 November. In the following years, Soviet historiography described the incident as Finnish provocation. Doubt on the official Soviet version was cast only in the late 1980s, during the policy of glasnost. The issue has continued to divide Russian historiography even after the end of the Soviet Union in 1991.
==== Soviet intentions ==== In 2013, Russian President Vladimir Putin stated at a meeting with military historians that the Soviets had launched the Winter War to "correct mistakes" made in determining the border with Finland after 1917. Opinion on the scale of the initial Soviet invasion decision is divided. The puppet Finnish communist government and the Molotov–Ribbentrop Pact's secret protocol is used as evidence that the Soviet Union had intended to conquer all of Finland. On 1 December 1939, the Soviet Union formed a puppet government, named the Finnish Democratic Republic, to govern Finland after Soviet conquest. A declaration delivered via TASS stated:
The People's Government in its present composition regards itself as a provisional government. Immediately upon arrival in Helsinki, capital of the country, it will be reorganised and its composition enlarged by the inclusion of representatives of the various parties and groups participating in the people's front of toilers. Soviet leaflets dropped over Helsinki on the first day of the war stated: "Finnish Comrades! We come to you not as conquerors, but as liberators of the Finnish people from the oppression of the capitalists and the landlords". In 1939, Soviet military leadership had formulated a realistic and comprehensive plan for the occupation of Finland. However, Joseph Stalin was not pleased with the conservative pace that the operation required and demanded new plans be drawn up. With the new plans, the key deadline for Finland's capitulation was to be Stalin's 60th birthday on 21 December. Convinced of the invasion's forthcoming success, Andrei Zhdanov, chairman of the highest legislative body in the Soviet Union, commissioned a celebratory piece of music from Dmitri Shostakovich, Suite on Finnish Themes, intended to be performed as the marching bands of the Red Army paraded through Helsinki. The Soviets were confident that the Western powers would not come to Finland's aid. Ivan Maisky, the Soviet ambassador to the UK, said: "Who would help? The Swedes? The British? The Americans? There's no way in hell. There will be a fuss in the press, moral support, moaning and whining. But troops, aircraft, cannons, and machine guns – no." Hungarian historian István Ravasz wrote that the Soviet Central Committee had set out in 1939 that the former borders of the Tsarist Empire were to be restored, including Finland. American political scientist Dan Reiter stated that the Soviets "sought to impose a regime change" and thus "achieve absolute victory". He quoted Molotov, who had commented in November 1939 on the regime change plan to a Soviet ambassador that the new government "will not be Soviet, but one of a democratic republic. Nobody is going to set up Soviets over there, but we hope it will be a government we can come to terms with as to ensure the security of Leningrad". According to Russian historian Yuri Kilin, the Soviet terms encompassed the strongest fortified approaches of the Finnish defences for a reason. He claimed that Stalin had little hope for such a deal but would play for time for the ongoing mobilisation. He stated the objective as being to secure Finland from being used as a staging ground by means of regime change. Others argue against the idea of a complete Soviet conquest. American historian William R. Trotter asserted that Stalin's objective was to secure Leningrad's flank from a possible German invasion through Finland. He stated that "the strongest argument" against a Soviet intention of full conquest is that it did not happen in either 1939 or during the Continuation War in 1944 even though Stalin "could have done so with comparative ease". Bradley Lightbody wrote that the "entire Soviet aim had been to make the Soviet border more secure". In 2002, Russian historian A. Chubaryan stated that no documents had been found in Russian archives that support a Soviet plan to annex Finland. Rather, the objective was to gain Finnish territory and to reinforce Soviet influence in the region. American historian Stephen Kotkin also shares the position that the Soviet Union did not aim for annexation. He points out the different treatment Finland was given, compared to the Baltics: unlike the pacts of mutual assistance that the Baltics were pressured into, resulting in their total Sovietization, the Soviets demanded limited territorial concessions from Finland, and even offered land in return, which would not have made sense if full Sovietization was intended. Also, according to Kotkin, Stalin seemed to be genuinely interested in reaching an agreement during the negotiations: he had personally attended six of the seven meetings with the Finns, and had multiple times reduced his demands. However, mutual mistrust and misunderstandings would mar the negotiations, producing an impasse.
Opposing forces
=== Soviet military plan === Before the war, Soviet leadership had expected total victory within a few weeks. The Red Army had just completed the invasion of eastern Poland at a cost of fewer than 4,000 casualties after Germany attacked Poland from the west. Stalin's expectations of a quick Soviet triumph were backed up by politician Andrei Zhdanov and military strategist Kliment Voroshilov, but other generals were more reserved. Red Army Chief of Staff Boris Shaposhnikov advocated a narrow-front assault right on the Karelian isthmus. Additionally, Shaposhnikov argued for a fuller build-up, extensive fire support and logistical preparations, a rational order of battle and the deployment of the army's best units. Zhdanov's military commander, Kirill Meretskov, reported, "The terrain of coming operations is split by lakes, rivers, swamps, and is almost entirely covered by forests.... The proper use of our forces will be difficult". These doubts were not reflected in Meretskov's troop deployments, and he publicly announced that the Finnish campaign would take two weeks at most. Soviet soldiers had even been warned not to cross the border mistakenly into Sweden. Stalin's purges in the 1930s had devastated the officer corps of the Red Army; those purged included three of its five marshals, 220 of its 264 division or higher-level commanders and 36,761 officers of all ranks. Fewer than half of all the officers remained. They were commonly replaced by soldiers who were less competent but more loyal to their superiors. Unit commanders were overseen by political commissars, whose approval was needed to approve and ratify military decisions, which they evaluated based on their political merits. The dual system further complicated the Soviet chain of command and annulled the independence of commanding officers. After the Soviet success at the Battles of Khalkhin Gol against Japan, on the Soviet Union's eastern border, Soviet High Command had divided into two factions. One side was represented by the Spanish Civil War veterans General Pavel Rychagov from the Soviet Air Forces; the tank expert General Dmitry Pavlov and Stalin's favourite general, Marshal Grigory Kulik, the chief of artillery. The other faction was led by Khalkhin Gol veterans General Georgy Zhukov of the Red Army and General Grigory Kravchenko of the Soviet Air Forces. Under this divided command structure, the lessons of the Soviet Union's "first real war on a massive scale using tanks, artillery, and aircraft" at Khalkin Gol went unheeded. As a result, Russian BT tanks were less successful during the Winter War, and it took the Soviet Union three months and over a million men to accomplish what Zhukov had managed at Khalkhin Gol in ten days (albeit in completely different circumstances).
Soviet order of battle
Soviet generals were impressed by the success of German Blitzkrieg tactics, but they had been tailored to conditions in Central Europe, with its dense well-mapped network of paved roads. Armies fighting there had recognised supply and communications centres, which could be easily targeted by armoured vehicle regiments. Finnish Army centres, in contrast, were deep inside the country. There were no paved roads, and even gravel or dirt roads were scarce. Most of the terrain consisted of trackless forests and swamps. The war correspondent John Langdon-Davies observed the landscape: "Every acre of its surface was created to be the despair of an attacking military force". Waging Blitzkrieg in Finland was a highly-difficult proposition, and according to Trotter, the Red Army failed to meet the level of tactical co-ordination and local initiative that would be required to execute such tactics in Finland. Commander of the Leningrad Military District Kiril Meretskov initially ran the overall operation against the Finns. The command was passed on 9 December 1939 to the General Staff Supreme Command (later known as Stavka), directly under Kliment Voroshilov (chairman), Nikolai Kuznetsov, Stalin and Boris Shaposhnikov. On 28 December, when Stalin asked for volunteers to take over military command, Semyon Timoshenko offered himself on the condition that he be allowed to implement Shaposhnikov's initial plan of a focused attack on the Karelian Isthmus to break the Mannerheim Line; it was accepted. In January 1940, the Leningrad Military District was reformed and renamed "North-Western Front". The Soviet forces were organised as follows:
The 7th Army, comprising nine divisions, a tank corps and three tank brigades, was located on the Karelian Isthmus. Its objective was to quickly overrun the Finnish defences on the Karelian Isthmus and conquer Viipuri. From there, the 7th Army was to continue towards Lappeenranta, then turn west towards Lahti, before the final push to the capital Helsinki. The force was later divided into the 7th and 13th Armies. The 8th Army, comprising six divisions and a tank brigade, was north of Lake Ladoga. Its mission was to execute a flanking manoeuvre around the northern shore of Lake Ladoga to strike at the rear of the Mannerheim Line. The 9th Army was positioned to strike into Central Finland through the Kainuu region. It was composed of three divisions with one more on its way. Its mission was to thrust westward to cut Finland in half. The 14th Army, comprising three divisions, was based in Murmansk. Its objectives were to capture the Arctic port of Petsamo and then advance to the town of Rovaniemi.
Finnish order of battle
The Finnish strategy was dictated by geography. The 1,340 km (830 mi) border with the Soviet Union was mostly impassable except along a handful of unpaved roads. In prewar calculations, the Finnish Defence Command, which had established its wartime headquarters at Mikkeli, had estimated seven Soviet divisions on the Karelian Isthmus and no more than five along the whole border north of Lake Ladoga. In the estimation, the manpower ratio would have favoured the attacker by three to one. The true ratio was much higher, however, since for example, 12 Soviet divisions were deployed north of Lake Ladoga. Finland had a large force of reservists that trained in regular maneuvers, some of whom had experience from the Finnish Civil War. The soldiers were also almost universally trained in basic survival techniques, such as skiing. While the Finnish Army was not able to equip all of its soldiers with proper uniforms at the outbreak of war, its reservists were equipped with warm civilian clothing. The sparsely populated, highly agrarian Finland had to draft so many of its working men that the Finnish economy became massively strained due to a lack of workers. An even greater problem than the lack of soldiers was the lack of materiel, as foreign shipments of anti-tank weapons and aircraft had arrived only in small quantities. Stockpiles of cartridges, shells, and fuel were sufficient to last only 19 to 60 days. The ammunition shortage meant that the Finns could seldom afford counter-battery or saturation fire. Finnish tank forces were operationally nonexistent. The ammunition situation was somewhat alleviated by the fact that the Finns were mostly armed with Mosin–Nagant rifles dating from the Finnish Civil War, which used the same 7.62×54mmR cartridge as the Red Army. Finnish soldiers occasionally resorted to looting the bodies of dead Soviet soldiers in order to maintain their supply of ammunition. The Finnish forces were positioned as follows:
The Army of the Isthmus was composed of six divisions under the command of Hugo Österman. The II Army Corps was positioned on its right flank and the III Army Corps, on its left flank. The IV Army Corps was located north of Lake Ladoga. It was composed of two divisions under Juho Heiskanen, who was soon replaced by Woldemar Hägglund. The North Finland Group was a collection of White Guards, border guards and drafted reservist units under Wiljo Tuompo.
Soviet invasion
=== Start of invasion and political operations === On 30 November 1939, Soviet forces invaded Finland with 21 divisions, totalling 450,000 men, and bombed Helsinki, killing about 100 citizens and destroying more than 50 buildings. In response to international criticism, Soviet Foreign Minister Vyacheslav Molotov stated that the Soviet Air Force was not bombing Finnish cities but rather dropping humanitarian aid to the starving Finnish population; the bombs were sarcastically dubbed Molotov bread baskets by Finns. The Finnish statesman J. K. Paasikivi commented that the Soviet attack without a declaration of war violated three separate non-aggression pacts: the Treaty of Tartu, which was signed in 1920, the non-aggression pact between Finland and the Soviet Union, which was signed in 1932 and again in 1934; and also the Covenant of the League of Nations, which the Soviet Union signed in 1934. Field Marshal C.G.E. Mannerheim was appointed Commander-in-Chief of the Finnish Defence Forces after the Soviet attack. In a further reshuffling, Aimo Cajander's caretaker cabinet was replaced by Risto Ryti and his cabinet, with Väinö Tanner as foreign minister because of opposition to Cajander's prewar politics. Finland brought the matter of the Soviet invasion before the League of Nations. The League expelled the Soviet Union on 14 December 1939 and exhorted its members to aid Finland. Headed by Otto Wille Kuusinen, the Finnish Democratic Republic puppet government operated in the parts of Finnish Karelia occupied by the Soviets, and was also referred to as the "Terijoki Government", after the village of Terijoki, the first settlement captured by the advancing Red Army. After the war, the puppet government was reabsorbed into the Soviet Union. From the very outset of the war, working-class Finns stood behind the legitimate government in Helsinki. Finnish national unity against the Soviet invasion was later called the spirit of the Winter War.
First battles and Soviet advance to Mannerheim Line
The array of Finnish defence structures that during the war started to be called the Mannerheim Line was located on the Karelian Isthmus approximately 30 to 75 km (19 to 47 mi) from the Soviet border. The Red Army soldiers on the Isthmus numbered 250,000, facing 130,000 Finns. The Finnish command deployed a defence in depth of about 21,000 men in the area in front of the Mannerheim Line to delay and damage the Red Army before it reached the line. In combat, the most severe cause of confusion among Finnish soldiers was Soviet tanks. The Finns had few anti-tank weapons and insufficient training in modern anti-tank tactics. According to Trotter, the favoured Soviet armoured tactic was a simple frontal charge, the weaknesses of which could be exploited. The Finns learned that at close range, tanks could be dealt with in many ways; for example, logs and crowbars jammed into the bogie wheels would often immobilise a tank. Soon, Finns fielded a better ad hoc weapon, the Molotov cocktail, a glass bottle filled with flammable liquids and with a simple hand-lit fuse. Molotov cocktails were eventually mass-produced by the Finnish Alko alcoholic-beverage corporation and bundled with matches with which to light them. 80 Soviet tanks were destroyed in the border zone engagements. By 6 December, all of the Finnish covering forces had withdrawn to the Mannerheim Line. The Red Army began its first major attack against the Line in Taipale – the area between the shore of Lake Ladoga, the Taipale river and the Suvanto waterway. Along the Suvanto sector, the Finns had a slight advantage of elevation and dry ground to dig into. The Finnish artillery had scouted the area and made fire plans in advance, anticipating a Soviet assault. The Battle of Taipale began with a forty-hour Soviet artillery preparation. After the barrage, Soviet infantry attacked across open ground but was repulsed with heavy casualties. From 6 to 12 December, the Red Army continued to try to engage using only a single division. Next, the Red Army strengthened its artillery and deployed tanks and the 150th Rifle Division forward to the Taipale front. On 14 December, the bolstered Soviet forces launched a new attack but were pushed back again. A third Soviet division entered the fight but performed poorly and panicked under shell fire. The assaults continued without success, and the Red Army suffered heavy losses. One typical Soviet attack during the battle lasted just an hour but left 1,000 dead and 27 tanks strewn on the ice. North of Lake Ladoga on the Ladoga Karelia front, the defending Finnish units relied on the terrain. Ladoga Karelia, a large forest wilderness, did not have road networks for the modern Red Army. The Soviet 8th Army had extended a new railroad line to the border, which could double the supply capability on the front. On 12 December, the advancing Soviet 139th Rifle Division, supported by the 56th Rifle Division, was defeated by a much smaller Finnish force under Paavo Talvela in Tolvajärvi, the first Finnish victory of the war. In Central and Northern Finland, roads were few and the terrain hostile. The Finns did not expect large-scale Soviet attacks, but the Soviets sent eight divisions, heavily supported by armour and artillery. The 155th Rifle Division attacked at Ilomantsi and Lieksa, and further north the 44th attacked at Kuhmo. The 163rd Rifle Division was deployed at Suomussalmi and ordered to cut Finland in half by advancing on Raate road. In Finnish Lapland, the Soviet 88th and 122nd Rifle Divisions attacked at Salla. The Arctic port of Petsamo was attacked by the 104th Mountain Rifle Division by sea and land, supported by naval gunfire.
Operations from December to January
Weather conditions
The winter of 1939–40 was exceptionally cold with the Karelian Isthmus experiencing a record low temperature of −43 °C (−45 °F) on 16 January 1940. At the beginning of the war, only those Finnish soldiers who were in active service had uniforms and weapons. The rest had to make do with their own clothing, which for many soldiers was their normal winter clothing with a semblance of insignia added. Finnish soldiers were skilled in cross-country skiing. The cold, snow, forest, and long hours of darkness were factors that the Finns could use to their advantage. The Finns dressed in layers, and the ski troopers wore a lightweight white snow cape. This snow-camouflage made the ski troopers almost invisible so that they could more easily execute guerrilla attacks against Soviet columns. At the beginning of the war, Soviet tanks were painted in standard olive drab and men dressed in regular khaki uniforms. Not until late January 1940 did the Soviets paint their equipment white and issue snowsuits to their infantry. Most Soviet soldiers had proper winter clothes, but this was not the case with every unit. In the Battle of Suomussalmi, thousands of Soviet soldiers died of frostbite. The Soviet troops also lacked skill in skiing, so soldiers were restricted to movement by road and were forced to move in long columns. The Red Army lacked proper winter tents, and troops had to sleep in improvised shelters. Some Soviet units incurred frostbite casualties as high as ten per cent even before crossing the Finnish border. However, the cold weather did give an advantage to Soviet tanks, as they could move over frozen terrain and bodies of water, rather than being immobilised in swamps and mud. According to Krivosheev, at least 61,506 Soviet troops were sick or frostbitten during the war.
Finnish guerrilla tactics
In battles from Ladoga Karelia to the Arctic port of Petsamo, the Finns used guerrilla tactics. The Red Army was superior in numbers and material, but Finns used the advantages of speed, manoeuvre warfare and economy of force. Particularly on the Ladoga Karelia front and during the Battle of Raate Road, the Finns isolated smaller portions of numerically superior Soviet forces. With Soviet forces divided into smaller groups, the Finns dealt with them individually and attacked from all sides. For many of the encircled Soviet troops in a pocket (called a motti in Finnish, originally meaning 1 m3 (35 cu ft) of firewood), staying alive was an ordeal comparable to combat. The men were freezing and starving and endured poor sanitary conditions. Historian William R. Trotter described these conditions as follows: "The Soviet soldier had no choice. If he refused to fight, he would be shot. If he tried to sneak through the forest, he would freeze to death. And surrender was no option for him; Soviet propaganda had told him how the Finns would torture prisoners to death." The problem however was that the Finns were mostly too weak to fully exploit their success. Some of the pockets of encircled Soviet soldiers held out for weeks and even months, binding a huge number of Finnish forces.
=== Battles of the Mannerheim Line === The terrain on the Karelian Isthmus did not allow guerrilla tactics, so the Finns were forced to resort to the more conventional Mannerheim Line, with its flanks protected by large bodies of water. Soviet propaganda claimed that it was as strong as or even stronger than the Maginot Line. Finnish historians, for their part, have belittled the line's strength, insisting that it was mostly conventional trenches and log-covered dugouts. The Finns had built 221 strong-points along the Karelian Isthmus, mostly in the early 1920s. Many were extended in the late 1930s. Despite these defensive preparations, even the most fortified section of the Mannerheim Line had only one reinforced-concrete bunker per kilometre. Overall, the line was weaker than similar lines in mainland Europe. According to the Finns, the real strength of the line was the "stubborn defenders with a lot of sisu" – a Finnish idiom roughly translated as "guts, fighting spirit". On the eastern side of the Isthmus, the Red Army attempted to break through the Mannerheim Line at the battle of Taipale. On the western side, Soviet units faced the Finnish line at Summa, near the city of Viipuri, on 16 December. The Finns had built 41 reinforced-concrete bunkers in the Summa area, making the defensive line in this area stronger than anywhere else on the Karelian Isthmus. Because of a mistake in planning, the nearby Munasuo swamp had a 1-kilometre (0.62 mi)-wide gap in the line. During the First Battle of Summa, a number of Soviet tanks broke through the thin line on 19 December, but the Soviets could not benefit from the situation because of insufficient co-operation between branches of service. The Finns remained in their trenches, allowing the Soviet tanks to move freely behind the Finnish line, as the Finns had no proper anti-tank weapons. The Finns succeeded in repelling the main Soviet assault. The tanks, stranded behind enemy lines, attacked the strongpoints at random until they were eventually destroyed, 20 in all. By 22 December, the battle ended in a Finnish victory. The Soviet advance was stopped at the Mannerheim Line. Red Army troops suffered from poor morale and a shortage of supplies, eventually refusing to participate in more suicidal frontal attacks. The Finns, led by General Harald Öhquist, decided to launch a counter-attack and encircle three Soviet divisions into a motti near Viipuri on 23 December. Öhquist's plan was bold; however it failed. The Finns lost 1,300 men, and the Soviets were later estimated to have lost a similar number.
Battles in Ladoga Karelia and North Karelia
The strength of the Red Army north of Lake Ladoga in Ladoga Karelia surprised the Finnish Headquarters. Two Finnish divisions were deployed there, the 12th Division led by Lauri Tiainen and the 13th Division led by Hannu Hannuksela. They also had a support group of three brigades, bringing their total strength to over 30,000. The Soviets deployed a division for almost every road leading west to the Finnish border. The 8th Army was led by Ivan Khabarov, who was replaced by Grigory Shtern on 13 December. The Soviets' mission was to destroy the Finnish troops in the area of Ladoga Karelia and advance into the area between Sortavala and Joensuu within 10 days. The Soviets had a 3:1 advantage in manpower and a 5:1 advantage in artillery, as well as air supremacy. Finnish forces panicked and retreated in front of the overwhelming Red Army. The commander of the Finnish IV Army Corps Juho Heiskanen was replaced by Woldemar Hägglund on 4 December. On 7 December, in the middle of the Ladoga Karelian front, Finnish units retreated near the small stream of Kollaa. The waterway itself did not offer protection, but alongside it, there were ridges up to 10 m (33 ft) high. The ensuing Battle of Kollaa lasted until the end of the war. A memorable quote, "Kollaa holds" (Finnish: Kollaa kestää) became a legendary motto among Finns. Further contributing to the legend of Kollaa was the sniper Simo Häyhä, dubbed "the White Death" in Finnish media, credited with over 500 kills in the war. Captain Aarne Juutilainen, dubbed "the Terror of Morocco", also became a living legend in the Battle of Kollaa. To the north, the Finns retreated from Ägläjärvi to Tolvajärvi on 5 December and then repelled a Soviet offensive in the battle of Tolvajärvi on 11 December. In the south, two Soviet divisions were united on the northern side of the Lake Ladoga coastal road. As before, these divisions were trapped as the more mobile Finnish units counterattacked from the north to flank the Soviet columns. On 19 December, the Finns temporarily ceased their assaults due to exhaustion. It was not until the period of 6–16 January 1940 that the Finns resumed their offensive, dividing Soviet divisions into smaller mottis. Contrary to Finnish expectations, the encircled Soviet divisions did not try to break through to the east but instead entrenched. They were expecting reinforcements and supplies to arrive by air. As the Finns lacked the necessary heavy artillery equipment and were short of men, they often did not directly attack the mottis they had created; instead, they worked to eliminate only the most dangerous threats. Often the motti tactic was not applied as a strategy, but as a Finnish adaptation to the behaviour of Soviet troops under fire. In spite of the cold and hunger, the Soviet troops did not surrender easily but fought bravely, often entrenching their tanks to be used as pillboxes and building timber dugouts. Some specialist Finnish soldiers were called in to attack the mottis; the most famous of them was Major Matti Aarnio, or "Motti-Matti" as he became known. In North Karelia, Soviet forces were outmanoeuvred at Ilomantsi and Lieksa. The Finns used effective guerrilla tactics, taking special advantage of their superior skiing skills and snow-white layered clothing and executing surprise ambushes and raids. By the end of December, the Soviets decided to retreat and transfer resources to more critical fronts.
Battles in Kainuu
The Suomussalmi–Raate engagement was a double operation which would later be used by military academics as a classic example of what well-led troops and innovative tactics can do against a much larger adversary. In 1939, Suomussalmi was a municipality of 4,000 inhabitants, with long lakes, wild forests and few roads. The Finnish command believed that the Soviets would not attack there, but the Red Army committed two divisions to the Kainuu area with orders to cross the wilderness, capture the city of Oulu and effectively cut Finland in two. There were two roads leading to Suomussalmi from the frontier: the northern Juntusranta road and the southern Raate road. The Battle of Raate Road, which occurred during the month-long Battle of Suomussalmi, resulted in one of the largest Soviet losses in the Winter War. The Soviet 44th and parts of the 163rd Rifle Division, comprising about 14,000 troops, were almost completely destroyed by a Finnish ambush as they marched along the forest road. A small unit blocked the Soviet advance while Finnish Colonel Hjalmar Siilasvuo and his 9th Division cut off the retreat route, split the enemy force into smaller mottis, and then proceeded to destroy the remnants in detail as they retreated. The Soviets suffered 7,000–9,000 casualties; the Finnish units, 400. The Finnish troops captured dozens of tanks, artillery pieces, anti-tank guns, hundreds of trucks, almost 2,000 horses, thousands of rifles, and much-needed ammunition and medical supplies. So sure of their victory had the Soviets been that a military band, complete with instruments, banners and notes, was travelling with the 44th Division to perform in a victory parade. The Finns found their instruments among the captured materiel.
Battles in Finnish Lapland
The Finnish area of Lapland, bestriding the Arctic Circle, is sparsely developed, with little daylight and persistent snow-cover during winter; the Finns expected nothing more than raiding parties and reconnaissance patrols. Instead, the Soviets sent full divisions. On 11 December, the Finns rearranged the defence of Lapland and detached the Lapland Group from the North Finland Group. The group was placed under the command of Kurt Wallenius. In southern Lapland, near the village of Salla, the Soviet 88th and 122nd Divisions, totalling 35,000 men, advanced. In the Battle of Salla, the Soviets proceeded easily to Salla, where the road split. Further ahead was Kemijärvi, while the fork to Pelkosenniemi led northwest. On 17 December, the Soviet northern group, comprising an infantry regiment, a battalion, and a company of tanks, was outflanked by a Finnish battalion. The 122nd retreated, abandoning much of its heavy equipment and vehicles. Following this success, the Finns shuttled reinforcements to the defensive line in front of Kemijärvi. The Soviets hammered the defensive line without success. The Finns counter-attacked, and the Soviets retreated to a new defensive line where they stayed for the rest of the war. To the north was Finland's only ice-free port in the Arctic, Petsamo. The Finns lacked the manpower to defend it fully, as the main front was distant at the Karelian Isthmus. In the Battle of Petsamo, the Soviet 104th Division attacked the Finnish 104th Independent Cover Company. The Finns abandoned Petsamo and concentrated on delaying actions. The area was treeless, windy, and relatively low, offering little defensible terrain. The almost constant darkness and extreme temperatures of the Lapland winter benefited the Finns, who executed guerrilla attacks against Soviet supply lines and patrols. As a result, the Soviet movements were halted by the efforts of one-fifth as many Finns.
Aerial warfare
=== Soviet Air Force === The Soviet Union enjoyed air superiority throughout the war. The Soviet Air Force, supporting the Red Army's invasion with about 2,500 aircraft (the most common type being Tupolev SB), was not as effective as the Soviets might have hoped. The material damage by the bomb raids was slight as Finland offered few valuable targets for strategic bombing. The city of Tampere was one of the most important targets because it was an important railway junction, and also housed State Aircraft Factory and the Tampere Linen and Iron Industry premises, which manufactured munitions and weapons, including grenade launchers. Often, targets were village depots with little value. The country had few modern highways in the interior, therefore making the railways the main targets for bombers. Rail tracks were cut thousands of times but the Finns hastily repaired them and service resumed within a matter of hours. The Soviet Air Force learned from its early mistakes, and by late February instituted more effective tactics. The largest bombing raid against the capital of Finland, Helsinki, occurred on the first day of the war. The capital was bombed only a few times thereafter. All in all, Soviet bombings cost Finland five per cent of its total man-hour production. Nevertheless, Soviet air attacks affected thousands of civilians, killing 957. The Soviets recorded 2,075 bombing attacks in 516 localities. The city of Viipuri, a major Soviet objective close to the Karelian Isthmus front, was almost levelled by nearly 12,000 bombs. No attacks on civilian targets were mentioned in Soviet radio or newspaper reports. In January 1940, the Soviet Pravda newspaper continued to lie that no civilian targets in Finland had been struck, even accidentally. It is estimated that the Soviet air force lost about 400 aircraft because of inclement weather, lack of fuel and tools, and during transport to the front. The Soviet Air Force flew approximately 44,000 sorties during the war.
