The Soviet offensive on the Karelian Isthmus

On 9 June 1944, three days after the Allied landings in Normandy, the Red Army struck at Finland. All day the artillery of the Leningrad Front and the ships of the Baltic Fleet pounded the Finnish defences at the western end of the Karelian Isthmus, while aircraft bombed positions and roads behind them. On the morning of 10 June infantry and tanks went into the attack. Within a single day they broke through the first Finnish line of defence at Valkeasaari, on the Gulf of Finland. So began the operation known to historians as the Vyborg–Petrozavodsk offensive: the heaviest fighting on the Finnish front since the Winter War. Soviet historiography dates it from 10 June, the day of the infantry assault. Many studies, however, begin it on 9 June, with the preparatory bombardment.

Chronicles of events record the day with the statement that, in the absence of agreement on a common border, Soviet forces launched an offensive against Finland in order to defeat it before moving on Berlin. That statement needs two qualifications. The talks of spring 1944 were not only about borders. Moscow also demanded the internment or expulsion of German troops, the demobilisation of the army and enormous reparations, and it was these conditions that Helsinki judged impossible to meet. The aim of the offensive, according to the Stavka directives cited in the literature, was to destroy the Finnish army, push the front back from Leningrad and knock Finland out of the war. The attack on Finland was indeed the first link in the Soviet summer campaign, preceding the great offensive in Belorussia. But the idea that the aim was to defeat Finland “before marching on Berlin” is a simplification by later commentators, not a formulation of Soviet plans.

After the failed talks

Since 1941 Finland had been fighting the Continuation War against the USSR, which it had entered alongside Germany in the summer of 1941. After the German defeat at Stalingrad the government in Helsinki began to look for a way out of the war. In February 1944 the former prime minister Juho Kusti Paasikivi met the Soviet ambassador Alexandra Kollontai in Stockholm – the stage known as the Finnish peace feelers. Moscow backed its diplomacy with force: in February Soviet long-range aviation carried out three great raids on Helsinki.

In March the Finns refused to accept the terms in advance – Finland rejected the Soviet conditions. At the end of March, however, Paasikivi and Carl Enckell went to Moscow. There they were told that Finland must return to the 1940 border, cede the Petsamo area, intern the Germans and pay 600 million dollars in reparations over five years. In April the government of Edwin Linkomies, with the backing of parliament, rejected these terms. On 22 April the Soviet side announced that Finland had rejected peace and that responsibility for the consequences lay with its government.

At the time the front had been in the calm of positional warfare for two and a half years. In January 1944 the Red Army had broken the siege of Leningrad and pushed Army Group North westwards. The Finnish positions on the Karelian Isthmus, however, still lay only about 30 kilometres from the city. For the Soviet command, removing them was the natural next step.

The plan and the forces

Preparations for the offensive began after Helsinki rejected the terms. The plan envisaged two blows. The Leningrad Front of General of the Army Leonid Govorov was to break through the defences of the Karelian Isthmus, take Viipuri (Vyborg) and push on westwards towards the River Kymijoki. Somewhat later, the Karelian Front of General of the Army Kirill Meretskov was to force the River Svir and retake East Karelia with Petrozavodsk. The two blows were to trap the Finnish forces between Lake Ladoga and the Saimaa lakes and destroy them before the old border.

Two armies were sent to the Isthmus: Lieutenant General Dmitri Gusev (PL)’s 21st Army, which was to deliver the main blow along the coast of the Gulf of Finland, and Lieutenant General Alexander Cherepanov’s 23rd Army, attacking closer to Ladoga. The Stavka reinforced the front with 11 divisions and a dozen or more tank and self-propelled gun regiments. According to figures cited in the literature, the Leningrad Front had on the Isthmus some 19 divisions, more than 220 batteries of artillery and rocket launchers (nearly 3,000 barrels) and about 1,500 aircraft of the 13th Air Army and the Baltic Fleet’s air arm. On the breakthrough sector at Valkeasaari up to 220 barrels were concentrated per kilometre of front. Support also came from the heavy fortress guns of Kronstadt and the ships of the fleet, including the battleship Oktyabrskaya Revolyutsiya and cruisers.

The Finns had been building fortifications on the Isthmus since 1940, but the work was far from finished. The first position was the so-called main line along the 1941 front. Some fifteen to twenty kilometres behind it ran the VT line (Vammelsuu–Taipale), partly with concrete bunkers. The third, the VKT line (Viipuri–Kuparsaari–Taipale), was still being built: near Viipuri work had begun only at the end of May 1944. Two Finnish corps stood on the Isthmus, including IV Corps on the coastal sector. According to Finnish studies some of the soldiers were on leave, and the command, despite intelligence reports of a Soviet concentration, did not expect an attack of such force.

The timing of the offensive was no accident. At the Tehran Conference Stalin had promised the Western Allies that the Red Army would attack in the summer, pinning the Germans down in the East when the Allies landed in France. The attack on Finland preceded the great offensive in Belorussia by less than two weeks. Pushing the Finns back from Leningrad and eliminating them from the war would also free forces for the Baltic axis.

9 and 10 June: the breakthrough

From the morning of 9 June hundreds of aircraft of the 13th Air Army appeared over the Finnish positions. The artillery of the Leningrad Front and the Baltic Fleet fired for about ten hours, destroying trenches, bunkers and wire on the Valkeasaari sector and along the gulf near Terijoki (Zelenogorsk). Reconnaissance in force on several sectors was intended to find the weak points in the defence. The weight of fire took the Finns by surprise. According to accounts cited by Finnish historians, some front-line units lost contact with their command on the very first day, and many soldiers abandoned their positions.

On the morning of 10 June, after another artillery preparation, the 21st Army went into the attack, spearheaded by the 30th Guards Rifle Corps. The Valkeasaari sector was held by the 1st Infantry Regiment of the Finnish 10th Division. By evening Soviet troops had taken the first lines of trenches and destroyed the defences across the whole width of the breakthrough, advancing, according to Soviet figures, a dozen or more kilometres. The 10th Division, shattered and scattered, fell back in disorder. The Finnish front on the western part of the Isthmus had ceased to exist within a single day.

The VT line and Mannerheim’s decisions

Marshal Carl Gustaf Mannerheim quickly realised that this was no local attack. On 10 June he ordered a division and a brigade to be moved from East Karelia to the Isthmus, and further units over the following days, including General Ruben Lagus’s Armoured Division, Finland’s only armoured division. The front-line units were ordered to fall back to the VT line. On 12 June Mannerheim asked Germany for military aid: above all aircraft, assault guns and anti-tank weapons.

On 13 June the leading units of the 21st Army reached the VT line. The next day, after a heavy artillery preparation, they attacked it at Kuuterselkä and Sahakylä, on the road from Terijoki to Viipuri. At Kuuterselkä the defence cracked that same day. On the night of 14/15 June Lagus’s Armoured Division counter-attacked but could not close the breach and suffered heavy losses. A few kilometres to the east, at Siiranmäki, the Finns used the German-supplied Panzerfaust and Panzerschreck anti-tank weapons for the first time and held their positions. According to figures cited in the literature, the Soviet 98th Rifle Corps alone lost 3,784 men there on 13–16 June, 887 of them killed.

A local success, however, could not save a line already broken at Kuuterselkä. In mid-June Lieutenant General Karl Lennart Oesch, until then commander of the Olonets Group between Ladoga and Onega, took command of all forces on the Isthmus. On 15 and 16 June Mannerheim decided to abandon the VT line and fall back to the unfinished VKT line, running from Viipuri through Kuparsaari on the Vuoksi to Taipale. At the same time he decided to shorten the front in East Karelia to free more divisions for the Isthmus. The forces there, weakened by the transfers, began preparing to withdraw from the Svir and the Olonets isthmus.

The withdrawal lasted almost a week. Finnish rearguards fought delaying actions, while trains brought reinforcements to the Isthmus from north of Ladoga. The Soviet pursuit failed to encircle any sizeable Finnish unit. On 16–17 June the first aircraft of Oberstleutnant Kurt Kuhlmey’s German air detachment arrived in Finland: Ju 87 dive bombers and Fw 190 fighter-bombers. On 18 June Govorov was promoted to Marshal of the Soviet Union for breaking the Finnish defences.

Its place in the war

The first phase of the offensive ended on 20 June with the capture of Viipuri, Finland’s second-largest city, which the Finns had defended four years earlier in the last days of the Winter War. This time the city fell after a brief fight. In eleven days the Leningrad Front had advanced more than 100 kilometres and taken two lines of fortifications, but it had not destroyed the Finnish army, which managed to man the VKT line and bring up reinforcements. On 21 June the Karelian Front joined the offensive on the Svir, and on 28 June the Red Army entered Petrozavodsk.

The defeat on the Isthmus had immediate political consequences. On the night of 21/22 June the Reich Foreign Minister, Joachim von Ribbentrop, flew into Helsinki. In return for further arms deliveries and reinforcements he demanded an undertaking that Finland would not conclude a separate peace. Finnish efforts to obtain Soviet terms, made in the same days, ended with a reply from Moscow demanding readiness to capitulate. On 26 June President Risto Ryti gave a personal undertaking in a letter to Hitler. The Germans then sent an assault gun brigade, an infantry division and thousands of anti-tank weapons.

On the VKT line, between the Bay of Viipuri and the Vuoksi, the Battle of Tali-Ihantala raged from 25 June to 9 July; Finnish historiography regards it as the largest battle ever fought in the Nordic countries. Soviet attempts to cross the Bay of Viipuri and the Vuoksi at Vuosalmi also failed to break through. In mid-July the Stavka ordered the Leningrad Front to go over to the defensive and transferred part of its forces, especially armour, to the Baltic front. North of Ladoga the fighting continued until August. At Ilomantsi the Finns encircled two Soviet divisions, most of whose men nevertheless managed to escape.

Both sides paid a high price for the summer fighting. According to Grigori Krivosheev’s figures, the irrecoverable losses of the Leningrad and Karelian Fronts in the whole operation came to 23,674 men, with 72,701 wounded and sick. According to Finnish figures, between 9 June and 15 July some 9,300 Finnish soldiers were killed on the Karelian Isthmus and 32,400 wounded. In East Karelia a further 3,600 or so were killed and 12,100 wounded.

The offensive did not reach its designated objective, the Kymijoki, but it achieved what the winter talks had not: it convinced Finland’s leaders that the war could not be won. On 1 August Ryti resigned, and on 4 August parliament elected Mannerheim president, which released the state from his predecessor’s personal undertaking. On 4 September Finland ceased fire, the Soviet side followed a day later, and on 19 September an armistice was signed in Moscow. Finland returned to the 1940 border, ceded the Petsamo area and had to remove the German troops from the country, which soon turned into the Lapland War. Unlike Germany’s other allies, however, Finland was not occupied by the Red Army. In Finnish memory the summer battles of 1944 are remembered as a defence that saved the country’s independence. Soviet historiography said less about them, as they ended with the offensive halted short of its objectives. For Joseph Stalin, however, what mattered most was that Finland was out of the war and the front at Leningrad had ceased to exist.