27 December - DAY 28 of Winter War
Eastern Isthmus: the Finnish counteroffensive at Taipale pushes the Russians back from Kelja around midday.
The Russians lose 2,000 men in the fighting at Lake Suvanto while 516 Finnish soldiers are killed.
Northern Finland: at Hulkonniemi in Suomussalmi, troops of the Finnish 9th Division launch their decisive assault to destroy the enemy's 163rd Division. The Russians are forced to withdraw from Suomussalmi.
Colonel Siilasvuo receives word that the entire Russian 44th Division is concentrated along the Raate road.
Ladoga Karelia: combat detachments of IV Army Corps commanded by Major-General Hägglund launch a broad counteroffensive which lays the basis for January's 'motti' battles. In Lieksa, the Finnish troops attacking in the region of Kivivaara reach the Russian border and take up defensive positions.
Finland's civil defence chief urges the public to make greater use of camouflage and other forms of protection: cars should be painted white and people should also carry with them white camouflage clothing.
Soviet leader Joseph Stalin expresses his appreciation to Otto Wille Kuusinen and his 'Finnish People's Government' for their 60th birthday greetings, and wishes them victory in their struggle.
In a radio lecture, Professor V.A. Koskenniemi likens Finland's fight to the struggle of the ancient Greeks against the great powers of the ancient world.
Daily losses: 205
AT-gun at Kiantajärvi.