Mannerheim Line

A line of defensive fortifications extending across the Karelian Isthmus from the Gulf of Finland to Lake Ladoga, the Mannerheim Line was named for Carl Gustav Emil von Mannerheim, the Finnish military commander and president who, as chairman of the Finnish defense council, advocated construction of the line and oversaw its construction. 

The Mannerheim Line was intended to defend against a Soviet invasion of Finland, and it was here that the most intense fighting of the Russo-Finnish War (Winter War) took place in 1939. 

The Mannerheim Line was first planned after the Finnish civil war, which followed the conclusion of World War I. Construction began in the 1920s and continued throughout the 1930s. When completed, the fortification line consisted of approximately 200 machine-gun emplacements encased in concrete bunkers. The Mannerheim Line was incomplete by the outbreak of the Russo- Finnish War but proved effective nonetheless. 

The great advantage of the Mannerheim Line over the more extensive and more famous Maginot Line built by the French along their border with Germany was in its use of the natural terrain to leverage the effectiveness of its defenses. Whereas the Maginot Line and other traditional line fortifications used massive bunkers and other artificial structures, the Mannerheim Line exploited such landscape features as boulders and fallen trees. Whereas the Maginot Line was exceedingly conspicuous, the Mannerheim Line was skillfully camouflaged and thus a far more effective defensive position. 

Although superior Red Army numbers eventually forced the surrender of Finland, the Mannerheim Line defenses stalled the Soviet advance for two very bloody months. Embarrassed by the cost of the invasion of Finland, Soviet commanders and politicians greatly exaggerated the extent and construction of the Mannerheim Line, as if to suggest that it was virtually impregnable. It was, in fact, for the most part a series of trenches and common field fortifications punctuated at considerable intervals by more substantial bunkers. Machine guns were the weapon of choice. The Mannerheim Line had virtually no artillery positions. Skillful defense by Finnish troops, not impregnable military architecture, was responsible for the effectiveness of the Mannerheim Line.

Air War

The Soviet-Finnish conflict in the winter of 1939-1940, mostly over strategically important territories of the Karelian Isthmus. The air operations demonstrated the abilities and constraints of airpower in action in severe weather and over difficult and heavily wooded terrain. At the outbreak of hostilities, the Soviet air force had assembled about 900 aircraft, expecting an easy and quick campaign. Then Finnish air force had 162 mostly obsolete aircraft of all types. 

Enjoying permanent air superiority in the course of the war, the Red Air Force was able to secure vulnerable rear areas from air strikes but failed to eliminate in a surprise strike the dispersed Finnish combat aircraft on the ground. Soviet airpower was engaged primarily in close support, air cover, and airlifting of assaulting troops in the Karelian Isthmus, some limited air operations in the Arctic area, as well as bombing raids on more than 160 rear targets. 

Despite large-scale employment of bombers in daytime and clear-weather raids, the Soviets were unable to undermine Finnish defenses, economic life, supply traffic, and morale. This was due to wintertime navigation problems, bombing inaccuracy, and the fierce Finnish air defense, which claimed 275-314 Soviet air losses (more than half of them bombers). 

The Finns also used fighters energetically and adapted to winter conditions: They equipped fighters with skis for takeoffs and landings on ice and snow. Their pilots demonstrated a higher level of combat skills compared to the Russian pilots. During the war, Finland received 240 aircraft of all types as well as volunteer pilots from Western countries, but massive aid was compromised by politics and logistical difficulties. 

The Soviets massed reinforcements (1,500-2,000 planes) in January-February 1940 and introduced some operational and tactical changes (nighttime and poor-weather bombing raids as well as fighter escorts). Nevertheless, the war was won by the Soviets mostly on the ground due to the dramatic disparity of forces involved. Moreover, the evident failure of the Soviet air campaign was one of the primary reasons the war went on for as long as it did. The total Russian war losses were 594 aircraft; the Finnish air force lost 62 planes from all causes.

Finnish Air Force (in Russo-Finnish Wars)

Seeds of tradition were sown in the Ilmailuvoimat (the Finnish Air Force) during the Winter War (30 November 1939-12 March 1940) against the Soviet Union. Finnish air operations hit their stride during the Continuation War, so called because it continued the conflict begun by the Soviets in 1939. The first real combat for the Ilmailuvoimat occurred during the Soviet invasion of Finland. In this war, the Finns scored 190 confirmed kills and more than 100 probables. They achieved a 16:1 ratio with the Soviets-in aerial combat, the Finns shot down 16 Soviets for every one of theirs the Soviets downed. 

The small and ill-equipped Ilmailuvoimat followed certain principals to ensure success. First, by concentrating its fighter power and using the element of surprise, it achieved temporary air superiority. Second, it flew in small, flexible formations. Next, it demanded that its pilots be skilled in aerobatics and combat maneuvers. Finally, Finnish pilots were continuously trained until they were masters in shooting accuracy. 

Although Finland did not share the Nazi political ideology, it still formed an alliance with Germany to defend itself against the Soviet Union. When Hitler invaded the Soviet Union on 22 June 1941, Finland went to war. The air force began the Continuation War with 120 fighters (Brewsters, Fiats, Curtisses, Morane-Saulniers, and Hurricanes) and 58 mostly obsolete reconnaissance planes. 

Initially, the Finns were quite successful against the Soviets, achieving a 32:1 exchange ratio. As the war went on, the Finnish forces became less effective despite the acquisition of limited numbers of German Messerschmitt Bf 109Gs and Junkers Ju 88s. 

The Battle of the Gulf of Finland is the best example of air operations during the war. The Finnish fighter pilots were successful, attaining an average exchange ratio of 25:1. Their strategy of focusing on aerial combat made the difference; raids on Soviet air bases were not worth the risk. The Soviets had no shortage of aircraft but lacked experienced pilots. By focusing on eliminating these trained Soviet pilots, the Finns achieved air superiority. 

The Soviets did not wish to spend what was necessary to defeat the Finns militarily, so on 4 September 1944 a peace agreement was signed. The Ilmailuvoimat again finished a war with more fighters than it started with. Finland ended with the largest proportion of aces in the world in relation to population. Most of the Finn aces survived the war.

Further reading: Chew, Allen F. The White Death: The Epic of the Soviet-Finnish Winter War. East Lansing: Michigan State University Press, 2002; Engle, Eloise, and Lauri Paananen. The Winter War: The Soviet Attack on Finland 1939-1940. Mechanicsburg, Pa.: Stackpole, 1992; Trotter, William R. The Winter War, the Russo- Finnish War of 1939-40. London: Aurum Press, 2003. Engle, Eloise, and Lauri Paanen. The Winter War: The Russo-Finnish Conflict, 1939-1940. New York: Charles Scribner's Sons, 1990. Luukanen, Eino. Fighter over Finland: The Memoirs of a Fighter Pilot. London: Macdonald, 1963. Nikunen, Lieutenant General (ret.) Heikki. The Finnish Air Force (FAF): A Historical Review. Helsinki: Finnish Air Force, 1993.

Finland’s Resistance 1940

Both the Nazi–Soviet Pact of 24 August 1939 and its coda in Moscow the following month gave Stalin a completely free hand in the north, and he moved swiftly to capitalize on it. Hoping to protect Leningrad against any future German attack, he tried to turn the Gulf of Finland into a Soviet seaway, even though its northern shore was Finnish and most of its southern shore Estonian. Latvia, Lithuania and Estonia were bullied into agreements that allowed the Red Army to be stationed at key points on their territory, and in June 1940 their sovereignty was extinguished altogether by effective annexation. Surrounded on three sides by mighty Russia, they had no real choice but to acquiesce. Finland was another matter, even though she had a tiny fraction of Russia’s population and an 800-mile border with her.

In October Stalin summoned the Finns to Moscow to be presented with Soviet demands. They sent the leader of the Social Democrat Party, Väinö Tanner, who has been described as ‘tough, tactless, stubborn and frequently bloody-minded’, a curious choice of representative when the survival of one’s nation was at stake. Meanwhile, they mobilized. Stalin and Molotov wanted a thirty-year lease on the naval base of Cape Hanko, the cession of the Arctic port of Petsamo and three small islands in the Gulf, as well as the moving back of the frontier on the Karelian Isthmus, which was presently only 15 miles from Leningrad. In return for these 1,066 square miles of territory, the Russians were willing to give Finland 2,134 square miles of Russian Karelia around Repola and Porajorpi.

On the face of it, the deal did not look unreasonable, but when considered strategically the key nodal points the Bolshevik leaders were demanding made it clear that Finnish sovereignty would be hopelessly compromised, and the Finns decided to fight rather than submit. Matters were not helped when Tanner mentioned his and Stalin’s supposedly shared Menshevik past, a libel on the Bolshevik leader. On 28 November the USSR abrogated its 1932 non-aggression treaty with Finland and two days later, without declaring war, the Russians bombed Helsinki and invaded Finland with 1.2 million men, opening a bitter 105-day struggle that some have likened to the Spartans’ stand at Thermopylae.

The world prepared to watch another small nation being crushed by a totalitarian monolith. The Finnish Army comprised ten divisions, with only thirty-six artillery pieces per division, all of pre-1918 vintage, and inadequate small arms (although they did have the excellent 9mm Suomi machine pistol), supported by few modern aircraft. ‘They lacked everything,’ one historian has noted, ‘except courage and discipline.’ The Russians, by contrast, came across the border with 1,500 tanks, 3,000 aircraft and a complete assumption of a quick victory, as in Poland. The Red Army divided its attack into four parts: the Seventh and Thirteenth Armies would smash through the Finnish defences on the Karelian Isthmus known as the Mannerheim Line and capture Viipuri (Viborg), the second city of Finland. Meanwhile the Eighth Army would march round the northern shore of Lake Lagoda to fall on Viipuri from the north. The Ninth Army would attack the waist of Finland, slicing it in two, and in the far north the Fourteenth Army would capture Petsamo and Nautsi, cutting the country off from the Arctic Sea. The comprehensiveness of the plan has been described by one military historian as ‘imaginative, flexible and totally unrealistic’.

Although the Fourteenth Army took its objectives in the first ten days, nothing else went right for the Russians for the next two months. The Seventh Army, comprising twelve divisions, three tank brigades and a mechanized corps, could not break through the wilderness of barbed wire, gun emplacements, anti-tank ‘dragons’ teeth’ and well-camouflaged pillboxes of the Mannerheim Line, which was fiercely defended. The frozen ground was so hard that the Red Army occasionally had to use dynamite to move enough earth to build makeshift trenches. Even though the Finns had never faced tanks before, and were woefully under-equipped with anti-tank weapons – at least until they captured them from the Russians – they devised makeshift ways of stopping their advance, including, ironically enough, ‘Molotov cocktails’ (bottles of petrol lit with rags). This proved easier in the early stages when Russian tanks were not supported closely enough by Russian infantry, and in the dark that descended early in the Arctic winter and stayed till late.

The seventy-two-year-old ‘Defender of Finland’ after whom the Line was named, Field Marshal Baron Carl von Mannerheim, proved an inspired leader throughout the campaign, keeping his reserves in the south and correctly predicting the Russians’ next moves, possibly because he had been an officer in the Tsarist Army throughout the Great War. Told by Moscow that the Finnish proletariat would welcome them as liberators, the Russian soldiers were shocked when the entire nation united behind ‘the Defender of Finland’ instead.

It was the five divisions of the Russian Ninth Army in the centre of the country that suffered the most. Although on the map the vast wastes might seem to favour an invader, the many forests and lakes channelled the Russian forces, unfamiliar with the terrain, into a series of ambushes as temperatures dipped in that unusually cold winter to as low as –50 Celsius. The Leningrad–Murmansk railway line had only one siding going off towards the Finnish border, and although the Russians took Salla in central Finland, they were flung back before they reached Kemijärvi. The Finns burnt their own farms and villages, booby-trapped farm animals, destroyed anything that could provide the Russians with food and shelter, and, equipped with skis and local knowledge, laid mines on tracks through the forests that were soon covered in snow. Wearing white camouflage uniforms, which inexplicably the Russians were not given, the Finns were nicknamed Bielaja Smert (White Death) by their bewildered enemy.

Further south, the Russian 163rd and 44th Divisions were annihilated around the ashes of the village of Suomussalmi, in a ferociously brilliant Finnish operation that ranks with any of the Second World War. A logging, fishing and hunting community of 4,000 people before the war, it was captured by the 163rd (Tula) Motorized Rifle Division on 9 December, but was then cut off by the Finnish 9th Brigade under Colonel Hjalmar Siilasvuo. Because their leaders had assumed an easy victory, many of the Russians had been sent into sub-Arctic Finland in December lacking winter clothes and felt boots, as the Finns discovered by listening to their radio transmissions, which were equally astonishingly sent en clair rather than in code. Freezing, starving and cut off from retreat by the Finnish 9th Brigade for a fortnight, the morale of the 163rd Division broke on Christmas Eve and they fled eastwards across the frozen Lake Kiantajärvi. The Finns then sent up two Bristol Blenheim medium bombers to smash the ice, sending tanks, horses, men and vehicles tumbling into the freezing water below. As the historian of the Russo-Finnish Winter War laconically records: ‘They are still there.’ The Russian 44th Division that had come to rescue the 163rd were within earshot of the débâcle, and could hear their comrades dying, but they were not given orders to move. On the night of New Year’s Day they became the next victims of the White Death, as the barometer dipped again to –30 Celsius. By constantly mortar-bombing their sixty field kitchens at mealtimes, the Finns kept the Russians short of hot food, and when the Russians lit fires the Finns machine-gunned them from the treetops, ‘easily picking out the dark silhouettes of the men against the snow’. The standard Red Army rifle, the single-shot bolt-action 7.62mm 1902 Moisin-Nagant, became inoperable when its gun-oil lubricant froze in conditions below –15 Celsius, and armoured vehicles either had to be kept running, at ruinous expense in fuel, or they would seize up and block the narrow passageways through the forest.

‘We don’t let them rest,’ said General Kurt Wallenius of the Finnish Northern Army; ‘we don’t let them sleep. This is a war of numbers against brains.’ Sleep for the 44th was next to impossible because of the vehicle engines, terrified horses, Finnish professional trackers and hunters who made excellent snipers, and even ‘the sharp reports of the trees as their very sap froze’. Those who resorted to vodka found that, despite the initial sense of warmth, body heat was ultimately lost. The slightest wounds exposed to the air froze and went gangrenous. Frozen corpses were piled up, one on top of the other, as the Finns methodically moved from sector to sector, wiping out Russian resistance. By 5 January, a thousand Russian prisoners had been taken, a further 700 soldiers had escaped back to the Russian lines, and over 27,000 had been killed, all for the loss of 900 Finns. As one of his officers remarked to Colonel Siilasvuo, ‘The wolves will eat well this winter.’ The Finns captured 42 tanks, 102 field guns and 300 vehicles at Suomussalmi, as well as thousands of the conical-shaped Red Army hats (budenovka) that they later used in deception operations. Indeed, they captured more military hardware than they received from outside sources, however much the League of Nations supported Finland’s struggle (expelling the USSR from its ranks on 14 December) and however much the Western Allies’ Supreme War Council debated sending aid (they agreed to it only on 5 February, by which time it was too late).

The loss of the two divisions at Suomussalmi, when compounded with the reversals at the Mannerheim Line and the victory of General Paavo Talvela, who destroyed the 139th and 75th Red Army Divisions at Tolvajärvi on Christmas Eve, sent a humiliating message around the globe for the USSR, even though the Finns could not follow up these successes for lack of troops (they were conscripting fifteen-year-olds as it was). Hitler in particular believed he learnt lessons about the performance of the Red Army that were to affect his decision to invade Russia the following year. Yet they were substantially the wrong ones.

Stalin’s purging of the officer corps in 1937 had seriously weakened the Red Army. The former Chief of Staff Marshal Tukhachevsky was shot, and with him died new thinking about the development of mass armoured formations operating deep inside enemy territory. General Konstantin Rokossovsky, one of those who were tortured during that time – though not shot despite his Polish origins – later said that purges were even worse for morale than when artillery fired on one’s own troops because it would have to have been very accurate artillery fire to achieve such damage. Three out of the five Soviet marshals were purged in 1937–8, thirteen of the fifteen army commanders, fifty-seven of the eighty-five corps commanders, 110 of the 195 divisional commanders and 220 of the 406 brigade commanders. In total, around 43,000 officers were killed or imprisoned, although 20,000 were later released. Yet no fewer than seventy-one out of the original eighty-five senior members of the USSR’s Military Council were dead by 1941. When Rokossovsky, who had been beaten so badly in prison that he lost eight teeth and had three ribs broken, reported to Stalin for duty after being reinstated, Stalin asked him where he had been. Rokossovsky told him, whereupon Stalin laughed and said, ‘A fine time you chose to go to prison!’ before getting down to business.

Although the Soviet forces were staggeringly badly led at the outset of the Winter War, they learnt quickly. A trusted member of the Supreme Soviet from its creation in 1937, General Semyon Timoshenko was sent to take over on 8 January, and after four or five attacks a day he broke through the Mannerheim Line on 13 February. In Finland the Soviets came to understand the importance of co-ordinating armour, infantry and artillery. However heavy the Russian losses, there were always fresh troops to fling into the struggle. As one Finn put it after the battle of Kuhmo, ‘There were more Russians than we had bullets.’ When the fighting became purely attritional on the Isthmus, the Finns simply could not carry on bleeding like the Russians could. Furthermore, the Winter War showed that men fought harder when patriotically defending the Soviet Motherland than when in attack. (That was eventually to apply to the German Fatherland too.) Instead of these lessons, Hitler learnt the almost banal one that Stalin had shot a lot of good generals in the late 1930s. He was not the only one, however; on 20 January 1940 Churchill said that Finland ‘had exposed for all to see the incapacity of the Red Army’.

On 11 February the Russian 123rd Division broke through the Mannerheim Line close to Summa, leading much of the Seventh Army through two days later. They then moved on to Viipuri. With neutral Norway and Sweden denying access across their territory to the Allies, Petsamo in Russian hands and Hitler closing off the eastern Baltic, no significant help was likely from the West. Since by March as much as one-fifth of his army had become casualties, and there were only 100 Finnish planes left to fight 800 Russian, Mannerheim urged the Government to negotiate, and the Treaty of Moscow was signed on 13 March, while Russian and Finnish troops were still engaged in hand-to-hand combat in central Viipuri. Except for the loss of the whole Karelian Isthmus, the terms were not very much worse from those demanded by Stalin and Molotov in November, before around 200,000 Russians and 25,000 Finns had died, and 680 Russian aircraft and 67 Finnish had been destroyed. Yet Russian military prestige had been severely damaged, and Stalin had created a situation on his north-western border that would require fifteen divisions to police. The moment that Finland sniffed her opportunity for revenge, at the time of Operation Barbarossa in June 1941, she seized it.

Ju-52 ”Kaleva”

 

Kaleva, registered OH-ALL, was a civilian Junkers Ju 52 passenger and transport plane, belonging to the Finnish carrier Aero O/Y. The aircraft was shot down by two Soviet Ilyushin DB-3 bombers during peacetime between the Soviet Union and Finland on June 14, 1940, while en route from Tallinn to Helsinki, killing all 9 on board.

A few minutes after taking off in Tallinn, Kaleva was joined at close range by two Soviet DB-3T torpedo bombers. The bombers opened fire with their machine guns and badly damaged Kaleva, making it crash into the water a few kilometers northeast of Keri Lighthouse. All nine passengers and crew members on board were killed.

Estonian fishermen had witnessed the attack and crash of the plane. Shortly after the crash the Soviet submarine Shch-301 surfaced and inspected the fishing boats. After confiscating items taken from the wreck by the fishermen, the Soviets picked up diplomatic mail from the wreck and the sea. The future top-scoring Finnish pilot Ilmari Juutilainen was sent to inspect the crash site. After the Soviets spotted the Finnish airplane, the submarine hid its flag.

At the time of the incident Finland was not at war with the Soviet Union. The attack was probably part of the Soviet preparations for the full-scale occupation of Estonia, which took place two days after the Kaleva incident, on 16 June 1940. The occupation was preceded for several days by a Soviet air and naval blockade, which included preventing diplomatic mail from being sent abroad from Estonia. The passengers on the last flight of Kaleva included two German businessmen, two French embassy couriers, one Swede, an American courier, and an Estonian woman. The French couriers had over 120 kilograms of diplomatic mail in the plane. The American courier was reportedly transporting the U.S. military codes to safety from Estonia.

The plane was piloted by Captain Bo von Willebrand, and Tauno Launis was the wireless operator. The American victim was Henry W. Antheil, Jr., younger brother of noted composer George Antheil. Antheil worked as a clerk at the U.S. Legation in Helsinki. In 2007, he was honored for his service in a ceremony at the U.S. Department of State. His name was inscribed on the U.S. Department of State's Wall of Honor.

The Government of Finland did not send any complaints or questions to the Soviets out of fear of hostile Soviet response, and the true reason for the crash was hidden from the public. This was due to the heavy pressure put upon Finland during the Interim Peace by the Soviets. After the outbreak of the Continuation War, the incident was described in detail by the government.

G. Golderg's report

The commander of Shch-301 G. Golderg's report on the incident held in the Russian State Naval Archives starts with the notice of a Finnish airplane on its way from Tallinn to Helsinki on June 14, 1940 at 15.05 PM. According to the report, the airplane was chased by two Soviet Tupolev SB high-speed bombers. At 15.06 PM, the Finnish airplane caught fire and fell into the sea, 5.8 miles from the submarine. At 15.09 PM the submarine took course to the crash site and made it to the location by 15.47 PM. The submarine was met by 3 Estonian fishing boats near the detritus of the airplane. The Estonian fishermen were searched by lieutenants Aladzhanov, Krainov and Shevtshenko. All valuables found from the fishermen and in the sea were brought on board of the submarine: the items included about 100 kg. of diplomatic post, valuables and foreign currencies. At 15.58 a Finnish fighter plane was noticed with the course towards the submarine. The airplane made 3 circles above the site and then flew towards Helsinki. The exact coordinates of the crash site were determined to be at 59°47′1″N 25°01′6″E.

A. Matvejev's report

Captain A. Matvejev's report states that on board the Shch-301 noticed an airplane crash on June 14, 1940 at 15.06 on 5.8 miles distance from the submarine. At the crash site 3 Estonian fishing boats and the remains of the airplane were found. At 15.58 PM a Finnish fighter plane made 3 circles above the crash site. By 16.10 PM all items found from the sea and from the hands of the fishermen were brought on board the submarine. The items included about 100 kg of diplomatic mail, and valuables and currencies including: 1) 2 golden medals, 2) 2000 Finnish marks, 3) 10.000 Romanian leus, 4)13.500 French francs, 5) 100 Yugoslav dinars, 6) 90 Italian liras, 7) 75 US dollars, 8) 521 Soviet rubles, 9) 10 Estonian kroons. All items were put on board of patrol boat "Sneg" and sent to Kronstadt.