"Both set during the 'Winter War' which occured in 1939-1940 between Finland and the Soviet Union (it was essentially a campaign of WW2). 'The Winter War (Talvisota)' (1989) is a little known Finnish film that has a great scale and accuracy to it.
I brought The Winter War in a DVD set with another Finish World War Two film (set in the Continuation War which followed the Winter War) named 'Ambush' (1999) also well worth seeing, Ambush I feel has a stronger narrative behind it with an officer "