The Soviet northern forces, also fearing encirclement from the Ägläjärvi area, abandoned their positions there on 8 August and fell back to the east of Kuolismaa.

On 20 July Heiskanen’s 11^th Divisioona had been relieved from Jänisjärvi lake and was moved first into reserve and then to the area between the 1^st Divisioona and the German 163^rd Division in the area of Hyrsylä on 11 August. The Soviets reinforced their forces in the area with the new 272^nd Division on 10 August, and began an immediate attack toward the Vieljärvi lake area against the 1^st Divisioona. In five days the Soviets managed to advance just 1.25 miles (2 km), and then only in a few places, before being halted. On 19 August the 11^th Divisioona itself went over to the offensive from Hyrsylä to the north, and reached the Petrozavodsk railway and the main road on the following day. From there the Finnish division continued to the north-east toward Suvilahti, which it took on 21 August, and to the north toward Tsalkki, the location of the last usable supply road available to the Soviets.

On 19 August the 2^nd Jääkäriprikaati, the Ratsuväkiprikaati and the German 307^th Infasnterieregiment stormed over the Aittojoki river. The Ratsuväkiprikaati tried to encircle the defending Soviet forces, but the latter recognised their precarious situation and quickly pulled back, managing to extricate most of their strength to the east before the 11^th Divisioona cut their line of retreat at Tsalkki on 23 August. With the capture of Suojärvi, the last town in Ladoga Karelia had been liberated.

Farther to the south, the Finns undertook a parallel offensive to liberate the Karelian isthmus under the supervision of Oesch’s Kannaksen V
Voimien Komentajan Päämaja (Headquarters of the Commander of the Isthmus Forces). Here, between the south-western shore of Lake Ladoga and the northern shore of the Gulf of Finland, the new headquarters, which had come into existence on 14 June, deployed three major formations in the form of Talvela’s II Armeijakunta, Laatikainen’s V Armeijakunta and Oesch’s IV Armeijakunta. The first comprised Blick’s 2^nd Divisioona, Eversti Niilo Hersalo’s 15^th Divisioona and Eversti Aaro Pajari’s 18^th Divisioona to the north of the Vuoksijoki river; the second comprised only Eversti Jussi Sihvo’s 10^th Divisioona; and the last comprised Eversti Kaarlo Viljanen’s 4^th Divisioona, Eversti Einar Vihma’s 12^th Divisioona and Eversti Claes Winell’s 8^th Divisioona defending the coast.

The V Armeijakunta was disbanded on 29 June, its headquarters being revised to become the headquarters of the new VI Armeijakunta, and the 10^th Divisioona was then attached first to the IV Armeijakunta and from a time late in July to the II Armeijakunta as a reserve.

Facing these were the Soviet XIX Corps (142^nd and 115^th Divisions) and L Corps (43^rd and 123^rd Divisions), with the X Mechanised Corps (21^st and 24^th Tank Divisions and 198^th Mechanised Division) in reserve and the divisional-strength 22^nd Karelian Fortified Region holding the coast. At the end of June the X Mechanised Corps was transferred to the area south-west of Leningrad to bolster the Soviet defence against the advance of Generalfeldmarschall Wilhelm Ritter von Leeb’s Heeresgruppe 'Nord' from the south-west, but left its 198^th Mechanised Division as the only Soviet reserve.

As the 'Jatkosota' started, each side had remained at first on the defensive, delivering only small company- or battalion-size probing attacks to improve their tactical positions. Their loss of reserves against the more pressing German assault to the south prompted the Soviets to retreat to a more defensible line at the northern end of the front and they also continued to fortify in depth, creating concrete and wooden strongpoints, digging trenches and laying minefields. The Finns advanced to keep contact, and this situation continued until 31 July and the start of the Finnish offensive. The Soviet fortification programme had been concentrated near the Vuoksijoki river and along the roads, so the Finns concentrated their forces for breakthroughs that were narrow but deep over roadless terrain with the support of pioneers building temporary supply roads through the forests and over the swamps.

Pajari’s 18^th Divisioona attacked through the forest against the most northern sector of the 115^th Division: rather than following roads, the Finnish division secured an initial crossroads and then advanced through the forest to the next road, where it repeated the process. The crossroads were occupied by stronger units, which had to defend against several Soviet counterattacks with armoured support. On 4 August the Finns managed to encircle and capture the Ilmee crossroads, thus forcing the Soviets to abandon their prepared positions between Ilmee and the border. The main thrust of Hersalo’s 15^th Divisioona fell on the 588^th Regiment of the 142^nd Division, and was again delivered on a width of only 1.25 miles (2 km) with the aid of concentrated artillery fire. After breaching the border fortifications, the division advanced 3.1 miles (5 km) through the forest before coming to the road, thereby bypassing the Soviet defences, which were encircled and captured individually by following units. After six days the 15^th Divisioona was only 1.85 miles (3 km) from the rail line linking Viipuri and Sortavala and 9.3 miles (15 km) from the western corner of Lake Ladoga, and thus close to encircling Soviet forces on its left side.

Blick’s 2^nd Divisioona decided to trap two battalions of the 461^st Regiment holding the village of Tyrjä by encircling the village from the east and pushing the defenders to the Tyrjänjärvi lake with the 7^th Rykmentti while the 28^th Rykmentti bypassed the village and advanced to the south. With the aid of artillery support the Soviets managed to hold for four days before the encirclement was complete. Some of the men were then able to escape through the forests, but most of them and all their heavy equipment were trapped to the village. The Finns also suffered heavy casualties in the fighting before the capture of Tyrjä opened the road toward the railway crossing at Elisenvaara, and on 5 August 5 the first Finnish units reached the rail line linking Viipuri and Sortavala.

On 4 August General Leytenant Mikhail N. Gerasimov, commanding the 23^rd Army, ordered the 198^th Division to call off its counterattack near Sortavala and move to the south and join the 142^nd Division in an attack on the advancing 2^nd Divisioona, the 43^rd and 115^th Divisions being instructed to check the Finnish reserves. The counterattack failed and the 115^th Division retreated to the Helisevänjoki river at a location where hills and the river formed good defensive positions against the 18^th Divisioona. This formation advanced to the Helisevänjoki river and reached the rail line linking Viipuri and Sortavala at the Inkilä crossroads on 8 August.

Sihvo’s 10^th Divisioona was ordered to advance in the area between the 15^th Divisioona and 18^th Divisioona, and on 6 August reached the rail line connecting Viipuri and Sortavala. The 10^th Divisioona continued to attack in the direction of the rail line linking Käkisalmi and Hiitola, but the Soviet forces managed to keep the rail and road lines open until 8 August, when the 10^th Divisioona captured the village of Hiitola. When the 10^th Divisioona's first troops reached Lake Ladoga on the next day, the last land connection to the Soviet troops on the north-western shore of Lake Ladoga was severed. The Soviets tried to reopen the connection with powerful counterattacks on 10/11 August, but were unsuccessful.

Meanwhile the 2^nd Divisioona's 28^th Rykmentti had captured the Elisenvaara rail junction on 9 August, thereby opening rail supply routes to the front from Finland. After the battle of Tyrjä, the 2^nd Divisioona's 7^th Rykmentti rested for two days as the divisional reserve before continuing the attack along the railway toward Lahdenpohja, which it captured on 8 August, thus dividing the Soviet forces what was now a beach-head. On the same day the 2^nd Divisioona was transferred to Eversti Einar Mäkinen’s new I Armeijakunta with an order to clear the northern part of the Soviet beach-head, while the 10^th Divisioona and 15^th Divisioona cleared the beach-head’s southern part, where the Soviets ordered the 142^nd and 198^th Divisions to withdraw to Kilpolansaari island for naval evacuation. This withdrawal was executed in an orderly fashion and the Finns were unable to encircle any significant Soviet forces. On 11 August the 15^th Divisioona captured the Hiitola railway junction, and on 13 August all the surviving Soviet forces had retreated to the Huiskonniemi peninsula and Kilpolansaari island. Under total air superiority, the Soviets managed to withdraw almost all their men, weapons and equipment from the beach-head and by 23 August the 15^th Divisioona, which had been left to maintain the pressure on the Soviets, had cleared the remaining rearguards from the island.

The Soviets planned to start a major counter-offensive on 10 August, and in expectation of this the 23^rd Army had received the 265^th Division as a reinforcements in the area of Räisälä. The offensive was not directed against the 10^th Divisioona and 18^th Divisioona, though, but rather toward the opening of passages to the the forces encircled on the north-western shore of Lake Ladoga. Coincidentally, the 18^th Divisioona had been resting, and was now ordered to continue its advance on the same day, so when the Soviet attack started at Inkilä, the Finns began their own effort only 3.1 miles (5 km) to the west. The Soviet offensive failed to gain ground, while the Finnish attack cut the Soviets' main supply route and a later Finnish counterattack forced the Soviet forces to retreat south. Finnish troops reached the Vuoksijoki river on 14 August at Antrea (now Kamennogorsk), where they continued clearing the river’s left bank.

The Soviets started to move forces from the south-western side of Viipuri to defend Enso (now Svetogorsk) and to make a counterattack toward Antrea on 16 August, but when the attack failed the Soviets were forced to evacuate the northern bank on 21 August. On the eastern side the Finns advanced to the south-east and reached Vuosalmi and the northern outlet of the Vuoksijoki river on 17 and 18 August respectively. The Finns immediately made an unopposed crossing of the Vuoksi river a short distance to the west of Vuosalmi on 17 August, and by 20 August had secured the beach-head.

The Soviet counterattack on the 10^th Divisioona began on 14 August and managed to push the Finns 1.25 miles (2 km) to the north before Finnish reinforcements arrived and checked the Soviet advance. The 10^th Divisioona left the shore of Lake Ladoga to the 36^th Rykmentti of the 15^th Divisioona and concentrated all of its strength against the 265^th Division at Räisälä (now Melnikovo). On 15 August the 10^th Divisioona began its own attack, which encircled the Soviet defenders of Räisälä on 17 August and captured the town on the next day. From there the division continued clearing the left bank of the Vuoksijoki river’s northern outlet. On 19 August the 43^rd Rykmentti of the 10^th Divisioona continued to attack southward, and reached Suvantojärvi on 21 August. From there it continued to the eastward with the same division’s 1^st Rykmentti.

With all their forces to the north of the Vuoksi river now threatened with encirclement, the Soviets started to retreat from Käkisalmi, which the Finns captured on 21 August. The Finnish attack to the south continued and, as the small border guard units were capable only of delaying this progress, the Finns reached the Taipaleenjoki river and the shore of Lake Ladoga on 23 August. Here the Finnish troops were unable to make an immediate crossing of the river.

The Stavka fully appreciated the serious nature of the Soviet predicament, and on 20 August ordered a retreat to the new but generally unprepared defence line extending from the south-western side of Viipuri northward to the Vuoksi river and then along this waterway to Lake Suvanto and along the Taipaleenjoki river to Lake Ladoga. This decision shortened the front line to a marked degree, but also meant the abandonment of defensive installations the Soviets had prepared along the border during the preceding months. The Finns were preparing to start their own attack along the southernmost part of the border, so when the Soviet retirement was spotted on 21 August, the Finnish forces were ordered into an immediate pursuit.

Although General Major Vladimir V. Kirpichnikov’s 43^rd Division managed to man new positions to the north and west of Viipuri, it was unable to prevent Vihma’s 12^th Divisioona from advancing along the right bank of the Vuoksijoki and establishing contact with the 18^th Division, which was enlarging its bridgehead at Vuosalmi, and during the evening of 22 August the whole right bank was in Finnish hands. General Major Fillip F. Aliabushev’s 123^rd Division was currently holding the south-western side of Viipuri, but much of this division’s strength, together with that of General Major Vasili F. Konkov’s 115^th Division which had retreated from the upper part of the Vuoksijoki river, was still disorganised as a result of its rapid retreat from their positions. Viljanen’s 4^th Divisioona advanced along the Saimaa Canal, pressing the 43^rd Division from the north. By 23 August the most southern Finnish formation, Winell’s 8^th Divisioona, had cleared the western shore of the Bay of Viipuri as far to the east as the Ykspäänjoki river and begun to prepare a crossing of the bay. During August 23, the Finns had managed to advance from the east to a point 5 miles (8 km) from Viipuri, but during the morning of the following day the 115^th and 123^rd Divisions started a counterattack on the Finnish forces to the east of Viipuri, probably trying to regain the initiative and force Finns back to the northern bank of the Vuoksijoki river. Aided by heavy artillery fire, the Soviets managed to push the Finns more than 3.1 miles (5 km) in some places, but could not break though the Finnish front, and with the arrival of the Finnish reserve, in the form of the 12^th Division's 26^th Regiment, which was already moving up as part of a planned troop rotation, the Soviets were in turn driven back to their starting positions on the following day.

The Soviet counterattack did not affect the 12^th Division's drive, which had already been ordered and now severed the main rail link between Viipuri and Leningrad on 25 August.

During the morning of 24 August, the 8^th Divisioona started to cross the Bay of Viipuri to the Lihiniemi peninsula using the 3/45^th Rykmentti, and secured the peninsula in the course of the same day. The Finns continued the attack on the next day, cutting last rail link from Viipuri during the afternoon, and enlarging their beach-head a short distance in width and depth during next two days.

The 12^th Divisioona had continued its offensive to the south-west, and cut the main road linking Viipuri and Leningrad on 27 August. On the next day the Stavka authorised the 23^rd Army to withdraw from Viipuri and establish a new defensive line along the course of the previous 'Mannerheim Line'. The Soviet forces began an immediate retreat and tried with great vigour to open the roads they needed. At Ylä-Somme they managed to open one road in the evening of 28 August, and during the night they were able to move several truck convoys along this, although under Finnish fire. The artillery fire caused Soviet losses of men and trucks, and the road gradually became so congested that only men on foot were able to pass. During the next two days, the Soviets tried repeatedly to open the rail line along the Bay of Viipuri, but late in the evening of 30 August the 3^rd Rykmentti of the 12^th Divisioona linked with the 8^th Divisioona, and the motti at Porlampai was overrun.

As their attempts to break out of the Finnish encirclement during the next day failed and as this encirclement tightened round them, the Soviets 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, however, and only small groups managed to escape during this last night. In the morning of the next day the remaining and now completely demoralised Soviet troops started to surrender: 9,000 men surrendered and bodies of another 7,000 were buried, but almost 12,000 men had managed to escape before the ring closed. In this victory the Finns also took 306 pieces of artillery, 55 tanks, 673 trucks, almost 300 tractors and about 4,500 horses.

Along the main road and rail lines between Viipuri and Leningrad, the Soviet order to retreat and form a new defensive line along the old 'Mannerheim Line' came too late, for on the same day the 12^th Divisioona captured Leipäsuo and continued its advance to the south-west in the direction of the Kuolemanjärvi river, and to the south-east along the rail line. The Soviet defences at the main road junction of Summa held, but the Finns encircled these defences by breaching the defences at Munasuo. Here the remnants of the 123^rd Division managed to check the Finnish advance in only few places, and continued their retreat toward Leningrad.

During the morning of 30 August the 12^th Divisioona cut the rail line linking Koivisto and Leningrad on the Kuolemanjärvi river, and reached the coast of the Gulf of Finland during the same day. At Vammelsuu the 12^th Divisioona cut the rail line during the evening of the same day, but failed to cut the main road. The division reached the Gulf of Finland here on the following morning. The attack continued east to the Terijoki river, which it reached on 31 August, and arrived at the old border at the Raja river on the next day.

The encircled Soviet forces at Koivisto retreated to the islands, from which they were evacuated to Leningrad by ships of the Soviet navy. The last Soviet defenders of Koivisto were evacuated on 1 November.

On the 12^th Divisioon's left flank, from 23 August the 18^th Divisioona attacked toa the south-east between the Muolaanjärvi river and the Vuoksijoki river and, by 26 August the division had broken through first lake isthmuses.

Meanwhile the first units of the 2^nd Divisioona were starting to relieve the 18^th Divisioona in the isthmus between the Kirkkojärvi and Punnusjärvi lakes, and the 10^th Divisioona those between the Punnusjärvi lake and the Vuoksijoki river.

After the mottis on the north-western shore of Lake Ladoga had been cleared, the I Armeijakunta was moved to the Vuoksi river, and here took the 10^th Divisioona and 15^th Divisioona under command. The 18^th Divisioona breached the second of the lake isthmuses on 27 August, and after a one-day pause continued its attack towards the Kivennapa (now Pervomaiskoye) crossroads, which it took on 29 August. The attack continued and reached the old border on 31 August. The 2^nd Divisioona also reached the old border on the same day. The 10^th Divisioona had a harder time of it as the 198^th Division had started to counterattack on 29 August.

The Finnish offensive started to gather greater momentum during 30 August, the day on which the 15^th Divisioona joined the attack from the other side of the Vuoksi river. The Valkjärvi lake railhead was captured on 31 August and, threatened with yet another encirclement, the Soviet forces were ordered to withdraw from the southern side of the Vuoksijoki river to positions behind the old border. The 15^th Divisioona followed the retreating Soviets closely, and by 2 September the Finns had reached the old border along its full length in the Karelian isthmus.

On 20 August, meanwhile, General Waldemar Erfurth, the senior German liaison officer at the Finnish headquarters, notified Mannerheim that Generalfeldmarschall Wilhelm Keitel, head of the Oberkommando der Wehrmacht, was about to request Finnish aid in the assault on Leningrad. Mannerheim explained the practical difficulties of the proposal and also revealed the opposition of both the Finnish political and military leadership to such aid. The government had decided at a time before the start of the campaign that Finland would not attack Leningrad, and only after the military leadership had exerted considerable pressure had the government accepted a modest advance across the old border to take superior defensive positions. When Keitel’s letter arrived, both President Ryti and Mannerheim prepared a negative answer. On 31 August Erfurth again contacted Mannerheim with the proposal that the Finns should cancel their attack into East Karelia and instead attack Leningrad. Ryti and Mannerheim again refused.

On 31 August Mannerheim ordered that the Finnish offensive be halted along the line linking the mouth of the Rajajoki river and Ohta, while the exact halt line on the stretch between Ohta and Lake Ladoga would be determined later, after the Finns had reached the old border there. The object was to shorten the front line without the need to attack the the 22^nd Karelian Fortified Region, which was the Soviet defensive area to the north of Leningrad.

In this last phase of the fighting on the Karelian isthmus, the Soviets had six infantry divisions and a number of independent battalions and regiments defending Leningrad from the north, but this nominally potent force was not as effective as it appeared since all of its formations and units were at half strength as a result of the previous hard fighting with the Finns.

The 12^th Divisioona had reached its objective by 1 September, but elsewhere the attack started on 2 September. The 18^th Divisioona took Mainila on this day and Valkeasaari (now Beloostrov) on the following day. By 7 September both the 18^th Division and 2^nd Divisioona had reached their objectives between the Rajajoki river and Ohta. Mäkinen, the commander of the I Armeijakunta, ordered his forces to advance to the line linking Ohta, Lempaalanjärvi lake and the old border at Lake Ladoga with the proviso that in the event of determined resistance was met the offensive was to be called to a halt.

On 4 September the attack began, and two days later the 10^th Divisioona encircled and destroyed the 941^st Regiment at Kirjasalo. The Finnish forces had reached all of their final objectives by 9 September, halted and assumed a defensive posture.

The Soviets quickly learned of the lessened Finnish pressure, and capitalised on this fact: on 5 September two divisions were transferred from the Karelian isthmus into the area lying to the south of the Leningrad to fight the German onslaught. Although the Finnish troops on the Karelian isthmus played no active part in the great siege of Leningrad, their mere presence contributed to the German effort by hampering the delivery of supplies of the city round and across Lake Ladoga.

Farther to the north, the Finnish offensive in East Karelia by the forces of the Karjalan Armeija followed the effective end of Finnish operations in Karelia Ladoga and the Karelian isthmus, and this period of more than one month was used for the strengthening of the forces in this area and the completion of their offensive plans in light of the fact that the Soviets had developed new fortified areas and strengthened their own forces.

When the encirclement battles on the western shore of Lake Ladoga were resolved, Svensson’s 7^th Divisioona was redeployed to the junction of the VI Armeijakunta and VII Armeijakunta, a position from which it could assist either of them. The Finnish offensive was launched during the early hours of 4 September at Tuulos, where the largest Finnish artillery barrage to date was unleashed. Immediately after the end of this barrage, the 5^th Divisioona crossed the Tuulosjoki river some 4.3 miles (7 km) from its mouth on Lake Ladoga at 05.00. While the river crossing was in itself easily accomplished, the Soviet defence soon strengthened. The Finnish armoured battalion followed the spearhead and helped to destroy strongpoints, and finally the shore road was severed at 11.00. A Soviet counterattack, launched two hours later, managed to encircle the Finns who had reached the shore road, however. When the situation seemed increasingly dangerous to his forces at 14.00, Karhu committed his reserve, the 4^th Valon Irrotus (light detachment), and with tank support this managed to break the encirclement at 17.30, and in the battle that followed scattered the Soviet forces and reached the coast of Lake Ladoga, thus cutting the retreat route of the forces still between them and the Tuulosjoki river. During the night the encircled Soviet forces were destroyed. The battle effectively shattered the Soviet 3^rd Marine Brigade and the 419^th and 452^nd Regiments, and thereby opened the route to Olonets.

With the breakthrough area secured, the Detachment 'Lagus' passed through the 5^th Divisioona toward Olonets, which it captured on 5 September after only a short fight. From there the detachment advanced through the night toward the Svir river, which its leading units reached at 05.00 on 7 September. Here the Irrottautuminen 'Marttinen' (Martinnen detachment ) was hived off the Irrottautuminen 'Lagus' with an armoured battalion, and pressed on to the east from Olonets to take the northern end of the rail bridge over the Svir river and sever the western branch of the Soviets' vital Murmansk railway on the morning of 8 September.

On the 5^th Divisioona's left flank, the 17^th Divisioona was not as successful, the Soviet 3^rd Division being able to hold its positions at Säntämä.

Farther to the north the 17^th Divisioona fared better, and its 13^th Rykmentti reached the road linking Olonets and Petrozavodsk on the evening of 5 September. Here the 34^th Rykmentti continued its advance to the south along this road. From Olonets the 44^th Rykmentti, which was part of the Irrottautuminen 'Lagus', started to move northward on 6 September along the road toward Nurmoila, which it took on the following morning. This meant that all of the 3^rd Division’s road communications had been cut, and this Soviet division quickly broke away from Säntämä and tried without success to recapture Nurmoila.

During 7 September the Finnish forces captured the whole length of the road between Nurmoila and the position held by the 34^th Rykmentti, but by abandoning their vehicles most of the 3^rd Division’s men managed to break through the Finnish lines on 8 September and cross the road to the east, thus escaping to the roadless forests there.

On reaching the Svir river, the 17^th Divisioon started to clear both banks toward the east from the bridge where tahe Murmansk railway crossed the Svir river. The Soviets had reinforced the area with the new 314^th Division and the Finnish advance was slow, but by 22 September the Finns had consolidated a bridgehead some 3.1 to 6.2 miles (5 to 10 km) deep and 25 miles (40 km) on the south bank of the Svir river.

On the 7^th Divisioona's northern flank , the 1^st Divisioona and 11^th Divisioona were preparing to attack along the road connecting Olonets and Petrozavodsk road, and took bridgeheads across the Säpsänjoki river on 31 August. As elsewhere, the Soviets had prepared defences along the roads, so the Finns advanced through the trackless forests to encircle the defending Soviet forces. On 7 September the Finnish advance cut the road linking Aunus and Petrozavodsk at a point to the north of the Prääsä crossroads, which was itself captured on the following day. This isolated the 9^th and 24^th Regiments of the 272^nd Division from their supply lines. The 1^st Divisioona attacked these forces and on 7 September reached the main road.

On 11 September the Soviets started a counterattack from both sides against the Finnish roadblock at Prääsä in an attempt to reopen the road to Petrozavodsk. The effort had failed by 13 September, and this meant that the Soviet forces had no other option than to abandon their heavy equipment and retreat to the east through the forests, which they did during the next three days. After the area had been cleared of Soviet forces, the 11^th Divisioona continued the attack on 20 September with an advance along the main road, cutting it every 1.25 mules (2 km) and thereby forcing the defenders to abandon their positions. By 24 September the 11^th Divisioona had reached the village of Puoliväli, just 12.5 miles (20 km) from Petrozavodsk on the western shore of Lake Ladoga.

Lagus had meanwhile gathered his forces at the rail bridge over the Svir river, and on 18 September resumed the offensive with an eastward attack along the river to the village of Ostretsina, where he turned to the north in the direction of the village of Latva.

Between 15 and 20 September the 7^th Divisioona had built more than 18.5 miles (30 km) of road through the swamps and marshy forests towards the station at Latva on the rail line to Murmansk. The object of these operations was the double encirclement of the 3^rd Division and a number of independent battalions which had prepared defences along the rail line and were supported by an armoured train, impenetrable by Finnish anti-tank weapons. The Finnish attack achieved surprise, cut the rail line severed and took Latva on 21 September. The encircled Soviet forces started an immediate retreat along the rail line to the north, and with the help of the armoured train managed to break out of the encirclement and pull back to the north on 22 September. Not bothering to wait for the end of the fighting at Latva station, Lagus ordered two battalions under the command of Everstiluutnantti Björkman to attack to the north from Latva village. On 24 September these two battalions reached the shore of Lake Onega at the village of Derevjannoje, thus severing the Soviet northern forces' last land connection with the area to the south of Petrozavodsk. On 25 September Lagus ordered Björkman to cut the rail line again near Petrozavodsk, a task he achieved two days later at Orsega. One day later still, Björkman’s force was only 2.5 miles (4 km) from Petrozavodsk but had to halt as the two battalions were needed in Orsega, where Soviets were trying to break out of encirclement.

On 29 September the Soviets managed to force their way out through the Finnish line at Orsega and advance 3l.1 miles (5 km) to the north before being halted. The 7^th Divisioona was following the Soviet forces and on 30 September there was fierce fighting at Orsega. The 9^th Rykmentti of the 7^th Divisioona attacked to the south along the road which followed the western shore of Lake Onega, and reached the Svir river on 2 October. An immediate crossing was planned but had to be postponed as the tired troops refused to cross the river during the night. The crossing was then made at 14.00 on 6 October, and in the course of the next week the 7^th Divisioona established a bridgehead 6.2 miles (10 km) deep on the southern bank of Svir river before the arrival of 114^th Division halted the Finnish advance. Both sides then dug in and started to create defensive positions.

On 26 September the 1^st Divisioona and 11^th Divisioona continued their attack toward Petrozavodsk. Appreciating the danger they were in, the Soviet forces started to evacuate Petrozavodsk, so when the 11^th Divisioona cut the main road and rail line to the north from Petrozavodsk on 30 September most of the Soviet forces had pulled back. The town’s last defenders were evacuated by water across Lake Onega, and the Finns captured Petrozavodsk during the morning of 1 October. The 3^rd Division realised that the road to the north was blocked, and after destroying its heavy equipment, including the armoured train, retreated to the forests and started a long trek to the south. The 30^th Rykmentti spearheaded the Finnish pursuit, and after two weeks it was only a few hundred men of the 3^rd Division who escaped over the Svir river.

On the 11^th Divisioona's left flank the 4^th Divisioona advanced along the rail line linking Sortavala and Petrozavodsk. The Soviets had created strong defences in this area before the 'Talvisota', so the Finnish advance was considerably slower than had been anticipated, and the 4^th Divisioona was still 7.5 miles (12 km) from Petrozavodsk when the town fell.

Farther to the north was the 'Oinonen' Ryhmä (2^nd Jääkäriprikaati and Ratsuväkiprikaati) with orders to advance to the north-east. There were only two roads through the forests which the 'Oinonen' Ryhmä could use, so the 71^st Division concentrated its strength to hold one of these and on 16/21 September could therefore drive the 2^nd Jääkäriprikaati back almost 6.2 miles (10 km) before being forced to retreat as the attack of the Ratsuväkiprikaati threatened it with encirclement. The 'Oinonen' Ryhmä continued its pressure on the 71^st Division, and reached the Vatselänjärvi lake on 29 September, thereby opening the way to the east.

After the capture of Petrozavodsk, the Army of Karelia was ordered to continue the offensive to the north along the rail line and capture the string of lake isthmuses up to the Suununjoki river. The 1^st Divisioona crossed the Bay of Petrozavodsk to Cape Gromovskoye on 2 October and had cleared the southern part of the cape by 7 October. The first isthmus was breached by the 4^th Divisioona on 5 October, but the Finnish advance was slowed by the 1072^nd Regiment’s rearguard actions. The 1^st Divisioona therefore took responsibility for the attack, and the 5^th Rykmentti was transferred from the 4^th Divisioona to the 1^st Divisioona. The newly arrived 29^th Rykmentti was despatched from Petrozavodsk to bolster the 1^st Divisioona still further, and on 18 October the Finns finally reached the Suununjoki river.

The 4^th Divisioona continued its attack to the north on the western side of the lakes, leaving only small detachments to secure the next two isthmuses, until it linked with the 'Oinonen' Ryhmä, which had advanced to the east in the direction of the isthmus between the Sunjärvi and Pälläjärvi lakes on 13 October. The Finnish attack continued northward along the western shore of the Pälläjärvi lake, and on 19 October the 4^th Divisioona captured the crossroads at the Juustjärvi lake, so opening the way toward Karhumäki before the 126^th Regiment passed the crossing, whereupon the Soviet regiment abandoned its heavy equipment and retreated to the north through the forests.

The 8^th Divisioona had been moved from the Karelian isthmus to the Porajärvi lake area, which had been captured by the 'Kuusjärvi' Prikaati on 12 October, when the Soviet forces started to retreat from their prepared positions as the 4^th Divisioona advanced toward the Juustjärvi lake. On 15 October the 8^th Divisioona, strengthened by the arrival of the 'Kuussaari' Prikaati, started the attack across the Suununjoki river and on 18 October captured the crossroads at the Jänkäjärvi lake, from which it continued toward the Juustjärvi lakje, where it met the 4^th Divisioona on 20 October, and toward the Seesjärvi lake which it reached on 19 October. The 8^th Divisioona continued to clear the southern shore of the Seesjärvi lake, and on 1 November took the village of Maaselkä before being compelled to halt by the arrival of the 289^th Division.

After a three-week pause for preparation, the Finns resumed their offensive on 21 November and drove the Soviets back against the lake’s western shore. The Soviets managed to escape over the frozen lake on 28 November. The Finns' attempt to take the station at Maaselkä failed after the 263^rd Division reached the station right before them. As it it was now clear that the offensive could not now be continued to the railway station, the 8^th Divisioona was ordered to prepare defensive positions.

The capture of the Juustjärvi area threatened the long right flank of Soviet forces defending the eastern bank of the Suununjoki river, so the 4^th Divisioona, reinforced with the 45^th Rykmentti, was ordered to advance to the shore of Lake Onega and isolate the Soviet forces in that area. The attack started on 20 October and by 24 October had taken the village of Mäntyselkä at the southern end of the Semsjärvi lake, but failed to advance from there. The 26^th Rykmentti was ordered to encircle the Soviets by passing round the lake, and in the early morning of 27 October it captured the village of Kumsa, thus severing the Soviet rear and forcing a Soviet retreat. Meanwhile the 45^th Rykmentti had advanced through the forest by small paths and improved them sufficiently for motor vehicles to use the route, and reached the railway near Käppäselkä station on 27 October. In the following two days the regiment captured the station and an armoured train which had become stuck there.

At the same time, 27 October, the main Finnish offensive across the Suununjoki river began, the Ratsuväkiprikaati securing the initial bridgehead. On the next day, the 2^nd Jääkäriprikaati crossed the river and advanced toward Kontupohja, while the Ratsuväkiprikaati turned to the north to race round the Santalanjärvi lake. On the following day the 1^st Divisioona also crossed the river and, with the 2^nd Jääkäriprikaati, attacked Kontupohja straight from the march. This first assault failed, and the Finns therefore paused to prepare their next assault.

The 313^rd Division defending Kontupohja had noticed that additional Finnish units were now threatening its line of communications to the north and therefore began to withdraw from Kontupohja during the evening of 2 November just before the Finnish assault planned for the following morning. The Finns captured the town, which had been destroyed by fire, before 24.00 and continued in pursuit of the Soviets. Despite the fact that the Cavalry Brigade had cut the railway line and the main road to the north, the Soviet division managed to retreat using the hastily built road between the main road and the lake’s shore.

The Soviet situation was now improving as the front shortened and had its flanks anchored on the the lakes. The arrival of reinforcements had also improved the balance of forces, which now took the form of three Finnish divisions and two brigades against four Soviet divisions and one brigade. The high hills to the south and west of Karhumäki also provided natural defensive positions which were improved by extensive field fortifications, and the Finnish advance stopped on November.

During the next two weeks the Finns planned a renewed offensive, and this began on 21 November as the 1^st Divisioona started an attack which drove a wedge 3.1 miles (5 km) deep into the Soviet defences before being stopped. On the northern side of Karhumäki, the 4^th Divisioona had to halt only 2.5 miles (4 km) from the centre of the town on 19 November. Another Finnish attempt began on 29 November, and by 2 December this had breached the town’s outer defences on the western side. Meanwhile Lagus’s 1^st Jääkäriprikaati had reached the front and was committed on 4 December. During the morning of the following day, the 4^th Divisioona and 1^st Jääkäriprikaati penetrated the Soviet line from the north and west respectively, and advanced to the town. The 2^nd Jääkäriprikaati followed immediately behind the 1^st Jääkäriprikaati and started the clearance of the town as the 1^st Jääkäriprikaati continued quickly to the east in the direction of Poventsa, which it reached on the next day, thus closing the White Sea Canal. Small units crossed the canal and advanced a short distance before returning to Poventsa, where they went onto the defensive. During the night of 8/9 December Soviet pioneers blew the canal’s locks, and the resulting flood broke the banks protecting Poventsa.

To the north of the Karjalan Armeija, Eversti Erkki Raapana’s 14^th Divisioona had been instructed to advance to the Rukajärvi lake in the area held by the 337^th Regiment of the 54^th Division and the 73^rd Border Guard Detachment. Here the Soviet defence was based on an area of field fortifications some 9.3 to 12.5 miles (15 to 20 km) deep. The first Finnish patrols crossed the border on 1 July, and the general advance started two days later. The defence managed to delay the Finnish advance, and it was 8 July before the Finns captured Repola. The advance continued 11 July as the Finns crossed the Lieksajärvi lake and started to encircle Soviet forces defending narrow isthmuses.

The Finns completed their envelopment by 21 July and, as their attempt to reopen the road to the east failed on 23 July, the Soviets started to evacuate personnel over the Roukkulanjärvi lake. The evacuation was only partially successful: more than 100 men were drowned and 300 captured. The Omelia motti surrendered on 24 July.

For lack the light units which might have be able to spearhead a rapid advance, the Finns were able to advance to the east only slowly, and the next battles were fought between 30 July and 12 August for control of the Ontrosenvaara hills, where the 54^th Division had been reinforced with elements of the 137^th Regiment and 71^st Border Guard Detachment. When these forces proved incapable of checking the Finnish attack, the 7^th Army ordered a new 27^th Division to be formed in the area. The Soviets had prepared positions on Rukavaara hill only a short distance to the east, the retreating forces manned these positions and managed to halt the Finnish advance for three weeks. On 3 September the Finns attacked once more, encircling the hill and forcing the defenders to evacuate their positions on 8 September. The Finns took the village of Rukajärvi on 11 September, and crossed the Onkajoki river on 15 September. After advancing only another 1.25 miles (2 km), the Finns reached new Soviet positions which they could not take straight off the march.

Though the 14^th Divisioona had not reached all its planned objectives, the target which Mannerheim had set had been achieved with the capture of the Rukajärvi lake area, so the 14^th Divisioona was ordered to halt and go over to the defensive.

In the sparsely populated northern half of the Finnish front, where the Germans had operational command, the objectives were the securing of the Finish port and nickel mines at Petsamo in 'Rentier' (i), the seizure of the port city of Murmansk and the severance of the rail line connecting this city with the rest of the USSR in 'Platinfuchs', and the seizure of Salla and Kestenga followed by an advance to the White Sea at Kandalaksha and Loukhi in 'Polarfuchs' (i) within the overall context of the 'Silberfuchs' plan. Murmansk was the only year-round ice-free port in the north of the USSR, and its availability as a base threatened the strategically important nickel mining industry at Petsamo.

'Silberfuchs' was undertaken by von Falkenhorst’s Armee 'Norwegen' using Dietl’s Gebirgskorps 'Norwegen' with the 2^nd Gebirgsdivision and 3^rd Gebirgsdivision in the north against Murmansk, Feige’s XXXVI Gebirgskorps with the 169^th Division, SS Kampfgruppe 'Nord' and Finnish 6^th Division in the centre against Salla and then Kandalaksha, and Siilasvuo’s Finnish III Armeijakunta with the Finnish 3^rd Divisioona in the south against Kestenga and Ukhta, and then Luki, Kem and Belomorsk.

Though military operations during 1942 and 1943 were limited, the Finnish front did see some fighting. Early in 1942 the forces of Frolov’s Karelian Front tried to retake Medvezhyegorsk, which had been lost to the Finns late in 1941 and, with the arrival of spring, the Soviets also went on the offensive on the Svir front as well as the Kiestinki region. All these Soviet offensives started promisingly, but were soon checked and then driven back as a result of the fact that the Soviets overextended their resources or ran into very determined Finnish resistance in prepared positions. After Finnish and German counterattacks in the Kiestinki area, the front had in fact moved very little.

In September 1942, the Soviets made another attempt at Kriv near Medvezhyegorsk, but in five days of fighting managed to push the Finns back only 545 yards (500 m) over a frontage of 0.6 mile (1 km).

Unconventional warfare was also fought in both the Finnish and Soviet wilderness areas. Finnish long-range reconnaissance patrols organised by both the Finnish headquarters using the 4^th Itsenäinen Pataljoona (independent battalion) and local units patrolled beyond the Soviet lines. In the summer of 1942 the Soviets had formed the 1^st Partisan Brigade, which was 'partisan' only in name as it was essentially a force of more than 600 men and women on long-range patrol. The 1^st Partisan Brigade was able to infiltrate beyond Finnish patrol lines but was found and largely destroyed early in August 1942 near the Seesjärvi lake. Partisan activity in East Karelia was supposedly focused primarily on Finnish military supply and communication targets, but almost two-thirds of the attacks on the Finnish side of the border targeted civilians, killing 200 persons and injuring 50.

Though Vitse Admiral Vladimir F. Tributs’s Red Banner Baltic Fleet entered the 'Great Patriotic War' and 'Jatkosota' in a strong position, the effective German use of mine warfare and air superiority, in combination with the German land forces' swift advance through the Baltic states toward Leningrad, forced the Soviet navy to evacuate its several Baltic Sea bases to Kronstadt and Leningrad at the head of the Gulf of Finland. The Soviet maritime evacuations from Tallinn and Hanko were very costly, and the withdrawal to the eastern end of the Gulf of Finland, left nearly the whole of the Baltic Sea as well as many of its islands to the Germans and Finns. Although the Soviet navy had departed in a great hurry, the naval mines it had managed to lay before and during the evacuations caused casualties both to the Germans and the Finns, including the loss of Ilmarinen, one of the two Finnish coastal defence ships.

Although Soviet submarines continued to be a limited threat to German traffic in the Baltic, the withdrawal of the Soviet navy in effect made the Baltic a 'German lake' until the second half of 1944. The Baltic Fleet still operated from the besieged city of Leningrad. Early in 1942 Soviet forces recaptured the island of Gogland but lost both Gogland and Bolshoi Tyuters to the Finns later in the spring of 1942. During the winter of 1941/42, the Baltic Fleet made the decision to use the large Soviet submarine fleet for offensive work. Though initial submarine operations in the summer of 1942 were successful, the German and Finnish navies soon stepped up their anti-submarine efforts, making the Soviet submarine operations later in 1942 very costly. The Soviets' submarine offensive persuaded the Germans to lay anti-submarine nets as well as supporting minefields between Porkkala and Naissaar, and this was a combination which proved an insurmountable obstacle for the Soviet submarines.

Finland began actively to consider a way to extricate itself from the war after the huge German defeat in the Battle of Stalingrad, which ended in February 1943, and a new cabinet was formed with peace as its highest priority. Negotiations were conducted intermittently during 1943/44 between Finland on the one side and the Western Allies and the USSR on the other, but no agreement was reached. Iosef Stalin, the Soviet leader, then decided to force Finland to surrender, and there followed a bombing campaign on Helsinki. In February 1944 this air campaign included three major air attacks involving a total of more than 6,000 sorties, but the Finnish anti-aircraft defences managed to repel the raids and only about 5% of the Soviet bombs hit their intended targets. Helsinki’s air defence arrangements included the strategic placing of searchlights and fires as decoys outside the city to lure the Soviet bombers to drop their payloads in what were actually unpopulated areas. Major air attacks also hit Oulu and Kotka, but because of radio intelligence and effective anti-aircraft defences, the number of casualties was small.

The start of the end for Finland was signalled by the launch of the Soviet 'Vyborg-Petrozavodsk Offensive Operation' on 9 June 1944, and on 4 September a ceasefire ended military actions on the Finnish side, the USSR ending hostilities exactly 24 hours later. An armistice was signed in Moscow on 19 September.

Finland had to make numerous concessions. The USSR regained the borders of 1940, with the addition of the Petsamo area, and the Porkkala peninsula near Helsinki was leased to the USSR as a naval base for 50 years. The Finnish army was to be demobilised rapidly, though Finland was first to expel all German troops from its territory within 14 days and, as the Germans did not leave Finland by the given deadline, the Finns had to fight their former co-belligerents in the Lapland War.

Finland was also required to clear the minefields in Karelia (including East Karelia) and in the Gulf of Finland.

As they retreated toward northern Norway in 'Birke', the German forces had also undertaken extensive mining of northern Finland. Mine-clearance proved to be a long undertaking, especially in the sea, and lasted to 1952: 100 Finnish soldiers were killed and more than 200 wounded during this effort, most of them in Lapland.

Large numbers of civilians who had been relocated into Finland from Karelia in 1939/40 had moved back into Karelia during the war, and now had to be evacuated once again: of the 260,000 civilians who had moved back into the Karelia only 19 chose to remain and become Soviet subjects.

The 'Jatkosota' had involved some 530,000 Finnish and 220,000 German troops, and the Soviet strength increased from 450,390 in June 1941 rising to 650,000 in June 1944. So far as casualties are concerned, the Finns lost 63,204 dead or missing, 158,000 wounded, 939 civilians killed in air raids, 190 civilians killed by Soviet partisans, and between 2,377 and 3,500 taken prisoner. The Germans lost 14,000 dead or missing and 37,000 wounded. According to the Finns, the Soviets lost 201,000 dead or missing, 64,000 taken prisoner, 385,000 wounded, 190,000 hospitalised by sickness, and between 4,000 and 7,000 civilians killed.