was led by Ivan Khabarov, who was replaced by Grigory Shtern on 13 December. The Soviets' mission was to destroy the Finnish troops in the area of Ladoga Karelia and advance into the area between Sortavala and Joensuu within 10 days. The Soviets had a 3:1 advantage in manpower and a 5:1 advantage in artillery, as well as air supremacy. Finnish forces panicked and retreated in front of the overwhelming Red Army. The commander of the Finnish IV Army Corps Juho Heiskanen was replaced by Woldemar Hägglund on 4 December. On 7 December, in the middle of the Ladoga Karelian front, Finnish units retreated near the small stream of Kollaa. The waterway itself did not offer protection, but alongside it, there were ridges up to high. The ensuing battle of Kollaa lasted until the end of the war. A memorable quote, "Kollaa holds" () became a legendary motto among Finns. Further contributing to the legend of Kollaa was the sniper Simo Häyhä, dubbed "the White Death" by Soviets, and credited with over 500 kills. Captain Aarne Juutilainen, dubbed "the Terror of Morocco", also became a living legend in the Battle of Kollaa. To the north, the Finns retreated from Ägläjärvi to Tolvajärvi on 5 December and then repelled a Soviet offensive in the battle of Tolvajärvi on 11 December. In the south, two Soviet divisions were united on the northern side of the Lake Ladoga coastal road. As before, these divisions were trapped as the more mobile Finnish units counterattacked from the north to flank the Soviet columns. On 19 December, the Finns temporarily ceased their assaults due to exhaustion. It was not until the period of 6–16 January 1940 that the Finns resumed their offensive, dividing Soviet divisions into smaller mottis. Contrary to Finnish expectations, the encircled Soviet divisions did not try to break through to the east but instead entrenched. They were expecting reinforcements and supplies to arrive by air. As the Finns lacked the necessary heavy artillery equipment and were short of men, they often did not directly attack the mottis they had created; instead, they worked to eliminate only the most dangerous threats. Often the motti tactic was not applied as a strategy, but as a Finnish adaptation to the behaviour of Soviet troops under fire. In spite of the cold and hunger, the Soviet troops did not surrender easily but fought bravely, often entrenching their