Häyhä served as a sniper for the Finnish Army during the 1939 – 40 Winter War between Finland and the Soviet Union . He was in the 6th Company of JR 34 during the Battle of Kollaa in temperatures between and , dressed completely in white camouflage . On the other hand , Soviet troops were not issued with white camouflage suits for most of the war , making them easily visible to snipers in winter conditions . Joseph Stalin had purged military experts in the late 1930s , and the Red Army was consequently highly disorganized
had purged military experts
Great Purge
Simo Häyhä