The Winter War started on November 30 1939 after Soviet Union has attacted Finland, and ended with the Moscow peace treaty on March 13 1940. Finland fought her defence battles in the Winter War without official help from abroad but Sweden gave a helping hand by sending a voluntary group of two battalions to Finland to attend to the defence during the final stage of the war. Finland achieved a defence victory in the war and maintained its independence, but under the terms of peace treaty had to cede some eastern parts and the border was drawn substantially westwards.

 

The Commander-in-Chief, Field Marshal C.G.E. Mannerheim decided together with the Finnish military command as early as March 1940 to fortify the new border, focusing on South Karelia in the Virolahti-Luumäki area. A voluntary group called Svenska Arbetskåren (SAK, The Swedish Work Group) with almost 1000 men was welcomed to assist in the fortification work in March 1940. Sweden's contribution was significant; the Swedes brought machinery, equipment and vehicles that remained with the Finns when they returned to their home country. The group came with a professional leadership, which made a quick start possible. Sweden also donated Finland 20 million Swedish crowns, corresponding to 235 million Finnish marks at the time, and constituting around 20 per cent of the financial budget for 1940.

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The fortification work was led by E.F. Hanell from Fortification office of the Army that gathered together construction engineers and officers trained in the engineer forces familiar with the subject matter.The main part of the troops that fought in the Karelian isthmus had already been assembled to Virolahti-Luumäki area and they now begun to fortify their new positions. Work districts for local management and work groups of 500 men to operate on the construction sites were established for the technically more demanding fixed fortification. The most demanding excavation and concrete constructions were handed out to construction entrepreneurs on contract agreements. The stuff in the work groups and districts consisted of hired civilians whereas the responsibility of the tactical planning was carried out by military staff. The fortification projects were located on sparsely popolated areas and therefore it was necessary to build roads and also living quarters for the workers.

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The total project workforce increased continuously in numbers and amounted to 35 000 men in March 1941. The food services in the construction sites were managed by the Women's patriotic defence organization Lotta Svärd which performed a multitude of tasks during both wars (the Winter War and the Continuation War). The number of the members of the Lotta Svärd working in the construction sites was at best around 2000.

 

Construction work ceased down as the Continuation War between The Soviet Union and Finland broke out on June 25, 1941. The Finnish field army, after a short defence phase begun an offensive to reoccypy the territories Finland has lost during the Winter War. Before early summer 1944 the fortification troops carried out mainly road and bridge construction works and repaired buildings in the reoccupied areas. After the Soviet large-scale offensive was staged against Finland in the Karelian isthmus on June 9. 1944, the Salpa-Line was again recognized as an important "last defence line". Efforts to repair and reinforce the constructons were taken up first in the Virolahti-Luumäki-Lappeenranta area. In the lake districts Saimaa and Pielinen the construction focused mostly on completing the unfinished artillery emplacements.

 

The Soviet offensive was repelled in the Gulf of Viborg and the Karelian isthmus by mid-July 1944.The last large-scale battles were fought in northern Karelia in the Ilomantsi front at the beginning of August. The armistice entered into force on September 4-5 and the truce on September 19, 1944. Finland lost the area she had managed to reoccupy and drew all her military forces behind the border defined in the Moscow Peace Treaty. The fortification work ended in the beginning of December 1944.

 

Source

Oinonen, Armi & Tolmunen, Arvo 2005: Matka Salpalinjalle.