Which two countries fought in the Battle of Suomussalmi in World War II?

The Battle of Suomussalmi occurred in the central part of Finland bordering the Soviet Union. It was fought between Finland and the Soviet Union from December 7, 1939 to January 8, 1940. The outcome was an overwhelming victory for the Finland

Three regiments and separate battalions comprising 11,500 Finnish forces battled an overwhelming combination of Soviet forces estimated at 28,000 to 29,5000 forces.

The battle is often cited as an example of how a small force, properly led and fighting in familiar terrain, can defeat a vastly numerically superior enemy. Multiple factors contributed to the Finnish victory.

First, the Finish troops possessed superior mobility due to skis and sleds while the Soviet heavy equipment had to confine their forces to roads.

Second, the Soviet strategy to divide Finland in half across this central region on the eastern border was unrealistic- the region was mostly forested marshland with mere logging trails. Mechanized Soviet divisions had to rely on those trails and became easy targets for the mobile Finnish ski troops.

Third, Finish strategy was flexible and often unorthodox. For example, Finnish troops targeted Soviet field kitchens, which demoralized Soviet soldiers fighting in sub-Arctic winter.

Fourth, the Soviet army was poorly equippped, especially regarding their winter camouflage clothing.

Lastly, there were multiple Soviet intelligence failures.

Casualties and losses were 2,700 Finnish to 12,972 Soviets.