Finnish reconquest of the Karelian Isthmus (1941)

The Finnish reconquest of the Karelian Isthmus (1941) refers to a military campaign carried out by Finland in 1941. It was part of what is commonly referred to as the Continuation War.

Early in the war Finnish forces liberated the Karelian Isthmus. It had been ceded to the Soviet Union on March 13, 1940, in the Moscow Peace Treaty, which marked the end of the Winter War.

Later, in the summer of 1944, the Soviet Union reconquered the southern part of the isthmus in the Vyborg-Petrozavodsk Offensive.

Initial setup of the forces
Between the Army of Karelia and Gulf of Finland there were three Finnish corps: II Corps (2.D, 15.D and 18.D) north of the Vuoksi River, V Corps (10.D) and IV Corps (4.D, 12.D and 8.D) defending the coast. On the Soviet side there were 19th Rifle Corps (142.D, 115.D), 50th Rifle Corps (43.D, 123.D), 10th Mechanised Corps (21.Armored D, 24.Arm. D. and 198.Mech. D) in reserve and the division-strength 22nd Karelian Fortified Region, which defended the coast. The Soviet X Mechanized Corps were transferred at the end of June from the Karelian Isthmus to the southwest of Leningrad to defend against advancing Germans but left 198.D as the only reserve to Soviet forces. The Finnish V Corps were disbanded and 10.D were attached first to IV Corps (Lt. Gen. Karl Lennart Oesch) and late July to II Corps (MJ.Gen. Taavetti Laatikainen) as a reserve. Both parties were first on the defensive, and only small, company or battalion size probing attacks were made by both sides to improve their own positions. The loss of reserves prompted the Soviets to retreat to more defensible lines at the northernmost part of the front and continued fortifying in depth, creating concrete and wooden strongpoints, digging trenches and laying minefields, although the Finns advanced to keep contact with the enemy. This situation continued until July 31, when the Finnish offensive began.

Advance to the Lake Ladoga
The Soviet fortification works had been concentrated near the river Vuoksi and along the roads, so the Finns concentrated their forces on narrow, deep breakthroughs over the roadless terrains which were supported by pioneers building temporary supply roads through the forests and over the swamps. The 18.D (Col. Pajari) attacked through the forest against the northernmost section of the Soviet 115.D and instead of following roads they secured a roadcrossing and advanced again over the forest to the next road where they did the same. The roadcrossings were occupied by stronger units, which had to defend against several armor supported Soviet counterattacks. During one of those counterattacks Private Vilho Rättö captured a Soviet AT gun and aiming through the barrel he managed to destroy four enemy tanks, earning him the first Mannerheim Cross granted to a private. Finally on August 4, the Finns managed to encircle and capture the Ilmee road crossing, thus forcing the Soviets to abandon their prepared positions between Ilmee and the border. The main thrust of 15.D (Col. Hersalo) was against the Soviet IR588/142.D, and concentrated the thrust against only a two kilometer wide section, where most of the artillery was concentrated. After breaching the border fortifications, they advanced five kilometers through the forest before coming to the road thus bypassing Soviet defences, which were encircled and captured one by one by forces coming behind the leading elements. After six days advance 15.D was only three kilometers from the Viipuri-Sortavala railroad and 15 km from the western corner of Lake Ladoga and close to encircling Soviet forces on its left side. The 2.D (Col. Blick) decided to encircle two battalions of Soviet IR461 which were defending Tyrjä village by encircling the village from east and pushing the defenders to Lake Tyrjänjärvi by using IR7/2.D while IR28/2.D passed the village and advanced southwards. While supported by artillery the Soviets managed to hold on four days, before the encirclement was complete. Some of the men were able to escape through the forests, but most of them and all their heavy equipment were trapped to the village. Also the Finns suffered heavy casualties in the fighting and the IR7 received the nickname Tyrjän rykmentti (Regiment of Tyrjä). The capture of Tyrjä opened road towards the Elisenvaara railway crossing and at August 5 the first Finnish units reached the Viipuri-Sortavala railroad.

The commander of the Soviet 23rd Army, Lt. Gen. M. Gerasimov, ordered on August 4 that 198th Rifle Division cease its counterattack near Sortavala and move south to attack advancing 2.D together with 142.D. Meanwhile 115.D and 43.D should tie up the Finnish reserves. Unfortunately this wasn't sufficient and 115.D retreated to river Helisevänjoki, where hills and a river formed good defensive positions against attacking 18.D. The 18.D advanced to the river Helisevänjoki and reached the Viipuri-Sortavala railroad at the Inkilä roadcrossing at August 8. The 10.D (Col. Sihvo) was ordered to advance between 15.D and 18.D and at August 6 they reached Viipuri Sortavala railroad. 10.D continued attack towards the Käkisalmi-Hiitola railroad, but Soviet forces managed to keep the railroad and road open until August 8, when 10.D captured the village of Hiitola. When the first troops of 10.D reached Lake Ladoga next day, the last land connection to Soviet troops defending the northwest coast of Lake Ladoga was severed. The Soviets tried to open the connection with strong counterattacks during August 10 and 11 but were unsuccessful.

Meanwhile IR28/2.D had captured the Elisenvaara railway junction on August 9, thus opening supply routes through railways from Finland. After the battle of Tyrjä IR7/2.D rested two days as a division reserve before continuing the attack along the railroad towards the town of Lahdenpohja, which it captured on August 8, thus dividing Soviet forces in the forming bridgehead. At the same day, 2.D was transferred to new I Corps with an order to clear northern Soviet bridgehead. It was left to 15.D and 10.D to clear southern bridgehead where Soviet 142.D and 198.D were ordered to withdraw to Kilpolansaari island for naval transport. This withdrawal was executed in an orderly fashion and Finns couldn't encircle any bigger enemy formations. At August 11 15.D captured the Hiitola railway junction, and at August 13 all Soviet forces had retreated to the Huiskonniemi peninsula and the Kilpolansaari island. Having total air superiority, the Soviets managed to withdraw almost all the men and material from the bridgehead and at August 23 15.D, which was left to press the Soviets, had cleared all remaining rearguards from the island.

Crossing the River Vuoksi
The Soviet intention was to start a large counteroffensive on August 10, and the 23rd Army had received 265.D reinforcements to the Räisälä area. The offensive was to be directed against 18.D and 10.D, the objective being to open roads to encircled forces on northwest coast of Lake Ladoga. Coincidentally, the 18.D had been resting and received order to continue advance on the same day, so when the Soviet attack started at Inkilä, Finns in turn started their own only 5 km westwards. While the Soviet attack failed to gain ground, Finnish attack managed to cut Soviets' main supply route and subsequent Finnish counterattack forced Soviet forces to retreat southwards while fighting delaying action and first Finnish troops reached the Vuoksi River at August 14 at Antrea (now Kamennogorsk), where they continued clearing the left shore of the river. Soviets started to move forces from southwestern side of Viipuri to defend Enso (now Svetogorsk) and to counterattack to Antrea at August 16, but when the attack failed, the Soviets were forced to evacuate northern shore at August 21. At the eastern side the Finns advanced southeastward and reached Vuosalmi at August 17 and northern outlet of river Vuoksi at August 18. Immediately, the Finns crossed River Vuoksi unopposed a few kilometers west of Vuosalmi at August 17, and by August 20 they had secured the beachhead.

The Soviet counterattack against 10.D started August 14 and it managed to push Finns 2 km northwards before Finnish reinforcements managed to stop it. The 10.D left the coast of Lake Ladoga to IR36/15.D and concentrated all of its forces against Soviet 265.D at Räisälä (now Melnikovo). At August 15 the 10.D started its own attack in which it encircled Soviet defenders in Räisälä at August 17 and captured it next day. From there it continued cleaning the left bank of northern outlet of River Vuoksi. At August 19 IR43/10.D continued attack southward and reached Lake Suvanto at August 21. From there it continued eastward with IR1/10.D. This threatened all Soviet forces north of Vuoksi with encirclement and they started retreating from Käkisalmi which was captured at August 21. The attack continued southward and as only small border guard units were capable to delay attackers, the river Taipaleenjoki and the shore of Lake Ladoga was reached at August 23, but the Finnish troops were unable to cross river on the move.

Capture of Viipuri and motti of Porlampi
STAVKA recognized the serious situation, and ordered at August 20 to retreat to the new, unprepared defence line running from the southwest side of Viipuri northwards to river Vuoksi and along it to Lake Suvanto and through river Taipaleenjoki to Lake Ladoga. This decision shortened the frontline considerably, but it also meant abandoning defensive installations they had prepared last months along the border. The Finns were preparing to start their own attack along the southernmost stretch of the border at, so when they noticed the Soviets leaving their positions at August 21, they were ordered to commence immediate pursuit. Although Soviet 43.D (MJ.Gen. V. Kirpitsnikov) managed to man new positions north and west of Viipuri, they were unable to prevent Finnish 12.D (Col. Vihma) to advance along the right bank of River Vuoksi and contact 18.D, which was enlarging their beachhead at Vuosalmi, and at the evening of August 22 the whole right bank was in Finnish hands. Soviet 123.D (MJ.Gen. F. Aljabusev) was defending the southwest side of Viipuri. Much of the troops of 123.D and of 115.D (MJ.Gen. Konjkov) which had retreated from upper Vuoksi were still unorganized due to fast retreat from their positions. The Finnish 4.D (Col. Viljanen) advanced along the Saimaa Canal, pressing Soviet 43.D from north. By August 23 the southernmost Finnish division, 8.D (Col. Winell), had cleared the western shore of the Bay of Viipuri up to the river Ykspäänjoki, and started to prepare the crossing of the bay.

During August 23, the Finns had managed to advance from the east to 8 km from Viipuri, but in the morning of August 24 Soviet 123.D and 115.D started a counteroffensive against Finnish forces east of Viipuri, probably trying to capture initiative and force Finns back to the northern side of River Vuoksi. Using heavy artillery fire, Soviets managed to push the defending Finns over 5 km backwards in places, but they didn't manage to create breaches to the front, and when the reserve of 12.D, IR26, which was already moving to the place for troop rotation, arrived, the Soviets were pushed back to their starting positions next day. The Soviet counterattack failed to affect the already-ordered attack by 12.D, which severed the main railroad connection between Viipuri and Leningrad at August 25.

At the morning of August 24, the Finnish 8.D started crossing the Bay of Viipuri with the forces of III/IR45 to Lihaniemi Peninsula which it secured during the same day. At the next day they continued their attack and managed to sever last railroad running from Viipuri during afternoon, and managed to enlage their beachhead few kilometers to every direction during next two days. The 12.D had continued their offensive southwest, and severed Viipuri-Leningrad main road at August 27. At August 28 STAVKA allowed the 23. Army to withdraw from Viipuri and form new a defensive line to approximately the same place where Mannerheim Line had been. The Soviet forces began immediate retreat and tried forcefully to open the roads. At Ylä-Somme they managed to open one road at the evening of August 28, and during the night they managed to move several truck trains through, although under Finnish fire. The artillery fire caused several casualties, and little by little the road become more and more congested until finally only men on foot were able to pass. During the next two days, the Soviets tried repeatedly to open the railroad line along the bay of Viipuri, but at the late evening of August 30 IR3/12.D reached the positions of the 8.D. The motti of Porlampi was ended.

As the Soviet attempts to open the encirclement during the next day failed and as Finnish encirclement tightened, they made a final attempt to save the men by abandoning all vehicles and trying to escape on foot through the forests. The ring was already too tight and only small groups managed to escape at this last night. In the next morning, demoralized troops started to surrender. 9,000 men surrendered and 7,000 were buried there, but almost 12,000 men had managed to escape before the ring closed. Also, the booty was abundant: 306 artillery pieces, 55 tanks, 673 trucks, almost 300 tractors and around 4,500 horses.

Advance to the old border
Along the main road and railroad between Viipuri and Leningrad, the Soviet order to retreat and form a new defensive line along the old Mannerheim Line came too late, as the 12.D at the same day captured Leipäsuo and continued advance southwest, towards Lake Kuolemanjärvi, and southeast, along the railroad. The Soviet defences at main road at Summa held, but the Finns encircled these defences by breaching the defences at Munasuo. The defending remains of Soviet 123.D managed to hold Finnish advance only few places and continued withdrawing towards Leningrad. At the morning of August 30 12.D cut the Koivisto-Leningrad railroad at Kuolemanjärvi and reached the Gulf of Finland during the same day. Also at Vammelsuu, 12.D cut the railroad at the same evening, but failed to cut main road. The Gulf was reached also here in the next morning, and the attack continued east to Terijoki, which was captured August 31 and reached old border at the river Rajajoki next day. The encircled Soviet forces at Koivisto retreated to the islands and Soviet fleet transferred them to Leningrad. The last defenders of Koivisto were evacuated November 1.

At the left side of 12.D from August 23 the 18.D started attacking southeast between Lake Muolaanjärvi and Vuoksi. By August 26, the first lake isthmuses had been breached. Meanwhile first units of 2.D were relieving the forces of the 18.D from the isthmus between Lake Kirkkojärvi and Lake Punnusjärvi and 10.D those from Lake Punnusjärvi to the river Vuoksi. After the mottis at the northwestern shores of Lake Ladoga had been cleared, I Corps was moved to the river Vuoksi where it took 10.D and 15.D to its command. The 18.D breached the second lake isthmuses August 27 and rested one day before continuing attack towards the Kivennapa (now Pervomaiskoye) road crossing which it captured August 29. The attack continued towards the old border which was reached August 31. Also the 2.D reached the old border at August 31. The 10.D had more troubles as Soviet 198.D had started its counterattack August 29. The Finnish attack started to gain speed during August 30, and also 15.D joined the attack from the other side of the river Vuoksi. The Valkjärvi railroad endpoint was captured at August 31 and because of the threat of encirclement, the Soviet forces were ordered to withdraw from the souther side of the river Vuoksi behind the old border. 15.D followed the retreating Soviets closely and by September 2 old border had been reached everywhere.

German pressure to attack Leningrad and the end of offensive
At August 20, General W. Erfurth notified Mannerheim that Field Marshal W. Wilhelm Keitel would send a letter describing where Finns were asked to attack Leningrad. Mannerheim explained practical difficulties of the proposal and presented the opposition of both the political and military leadership to this attack. The government had decided beforehand that Finland would not attack Leningrad, and only after the pressure of military leadership they accepted a small advance across the old border to capture better defensive positions. The social democrats especially opposed crossing the border. When Keitel's letter came, Ryti and Mannerheim together prepared a negative answer. On August 31, Erfurth contacted Mannerheim again and proposed that Finns should cancel the attack to East Karelia and instead attack Leningrad. Ryti and Mannerheim again refused. On August 31 Mannerheim gave the order that the attack be stopped at the line from the mouth of the river Rajajoki to Ohta. The exact line between Ohta and Lake Ladoga would be ordered later, when the Finns had reached the old border there. That would shorten the frontline without the need to attack Soviet fortifications north of Leningrad (KaUR). In this last phase, the Soviets had six infantry divisions and a number of separate battalions and regiments defending Leningrad from the north, but all of them were at half strength due to the hard fighting with the Finns.

12.D had reached the target already on September 1, but elsewhere the attack started on September 2. 18.D captured Mainila at the same day and Valkeasaari (now Beloostrov) at next day. By September 7 both 18.D and 2.D had reached their targets between River Rajajoki and Ohta. The commander of I Corps, Colonel Mäkinen, ordered his troops to advance to the line Ohta-Lake Lempaalanjärvi-Old border at Lake Ladoga with an addition, that if strong defences were met, the offensive could be stopped there. At September 4 the attack began, and at September 6 10.D managed to encircle and destroy Soviet IR941 at Kirjasalo. Finally at September 9 the ordered line was reached everywhere and Finnish forces moved to the defensive.

The Soviet military leadership quickly learned of lessened Finnish pressure, and already at September 5 two divisions were transferred from Karelian Isthmus to the south of the city, against the Germans. Although the Finnish troops on the Karelian Isthmus didn't actively participate in the Siege of Leningrad, merely just their existence contributed to the siege by hampering the supply of the city around and across the Lake Ladoga.

Half of the Finnish part of the Isthmus was reconquered by the Soviet Union in the Fourth strategic offensive in 1944.