Stalin’s 60th birthday (official).
Soviet attacks on the Mannerheim Line weaken. Finns attack at Suomussalmi and Ägläjärvi. In Lapland, Soviet 122nd division is stopped at the villages of Pelkosenniemi and Kemijärvi (having advanced 45 miles since Nov 30) and will gradually be pushed back 20 miles to Salla (Battle of Salla). The Red Army had planned to be in Helsinki by Stalin’s birthday but the Finns clearly have the advantage. General Hugo Österman, Finnish commander on the Karelian Isthmus, boldly presents CiC Field Marshall Mannerheim with a plan for a counterattack on the Isthmus (prepared by II Corp’s commander General Harald Öhqvist).
Between 7.25 and 10.16 AM, U-21 sinks 2 small neutral Swedish merchant ships SS Mars and SS Carl Henckel with one torpedo each. picks up no survivors and 28 men die overnight. 1 survivor from Mars and 7 from Carl Henckel are picked up the next day and taken to Kristiansand.