conduct an active defense by crossing the border, stopping the advance of the Soviet regiment that was expected in the area and harassing the Soviet lines of communications, thereby tying down Soviet forces. The Finnish general staff considered the force insufficient for even this mission, but could not spare any more troops from the more important Karelian Isthmus. As Finland undertook a general mobilization in October 1939, the troops had time to take stock of the situation and came to the conclusion that even limited offensive operations across the border were beyond their capabilities and afterwards only defensive and delaying operations were practiced in training. A Finnish intelligence estimate on 15 October placed one Soviet division in the Murmansk-Kandalaksha area. The Finns expected a larger Soviet force concentration in the future. On 30 November, the Soviets had four divisions in the area. Military geography Southern Lapland is 80% covered by forests or swamps. The geography is dominated by forest-covered fells that surround large swamps and lakes. In December 1939 the lakes and swamps were not yet sufficiently frozen over to support motor vehicle movement but this became irrelevant as the winter progressed and the temperature dropped to -40°, which also made military operations more difficult. Movement outside roads was thus impossible for large military formations. Only one road existed from the Soviet border to Salla. The road network was better developed west of it, with numerous small roads to support lateral movements and the encirclement of defending forces. Order of battle Finland There were only a few Finnish troops in the area at the start of the war. The 17th Separate Battalion (Er.P 17) or the "Salla Battalion" was mobilized before the war. Its main components came from a company of the Frontier Guard. From 11 December 1939 onward the Finnish troops were part of the Lapland Group (Lapin Ryhmä) which was commanded by Major General Kurt Martti Wallenius. After 5 December infantry, artillery, mortar and anti-tank units were to reinforce the defenders. The total number of Finnish forces in the area was 3,500. Soviet Union The Soviets attacked with 122nd Rifle Division. The stalling of the offensive forced the Soviets to reinforce it in late December 1939 with the 88th Rifle Division. The battle Soviet troops pushed the Finns up to the Kemijoki river, but were unable to break through the Finnish defences on the river. The Soviet supply