Finland lost territories in the 3½ month Winter War against the Soviets, November 1939 to March 1940.
[1] During the mobilization prior to the Winter War, the 6th Division was placed in the reserve of the Commander-in-Chief Gustaf Mannerheim.
In February the Soviet forces began bombarding the front lines at Summa with artillery fire.
On the morning of 11 February, the attack began along the whole front of the exhausted 3rd Division.
The Soviets had concentrated nine divisions and five armoured brigades of the 7th Army at Summa.