restricted to movement by road and were forced to move in long columns. The Red Army lacked proper winter tents, and troops had to sleep in improvised shelters. Some Soviet units incurred frostbite casualties as high as ten percent even before crossing the Finnish border. However, the cold weather did give an advantage to Soviet tanks, as they could move over frozen terrain and bodies of water, rather than being immobilised in swamps and mud. According to Krivosheev, at least 61,506 Soviet troops were sick or frostbitten during the war. Finnish guerrilla tactics In battles from Ladoga Karelia to the Arctic port of Petsamo, the Finns used guerrilla tactics. The Red Army was superior in numbers and material, but Finns used the advantages of speed, manoeuvre warfare and economy of force. Particularly on the Ladoga Karelia front and during the Battle of Raate Road, the Finns isolated smaller portions of numerically superior Soviet forces. With Soviet forces divided into smaller groups, the Finns dealt with them individually and attacked from all sides. For many of the encircled Soviet troops in a pocket (called a motti in Finnish, originally meaning of firewood), staying alive was an ordeal comparable to combat. The men were freezing and starving and endured poor sanitary conditions. Historian William R. Trotter described these conditions as follows: "The Soviet soldier had no choice. If he refused to fight, he would be shot. If he tried to sneak through the forest, he would freeze to death. And surrender was no option for him; Soviet propaganda had told him how the Finns would torture prisoners to death." The problem however was that the Finns were mostly too weak to fully exploit their success. Some of the pockets of encircled Soviet soldiers held out for weeks and even months, binding a huge number of Finnish forces. Battles of the Mannerheim Line The terrain on the Karelian Isthmus did not allow guerrilla tactics, so the Finns were forced to resort to the more conventional Mannerheim Line, with its flanks protected by large bodies of water. Soviet propaganda claimed that it was as strong as or even stronger than the Maginot Line. Finnish historians, for their part, have belittled the line's strength, insisting that it was mostly conventional trenches and log-covered dugouts. The Finns had built 221 strong-points along the Karelian Isthmus, mostly in the early 1920s. Many were extended in the late