Soviet–Finnish relations and politics
Until the beginning of the 19th century, Finland constituted the eastern part of the Kingdom of Sweden. From 21 February 1808 to 17 September 1809, the Russian Empirewaged

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Soviet military plan
Before the war, Soviet leadership expected total victory within a few weeks. The Red Army had just completed

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Start of the invasion and political operations
On 30 November 1939, Soviet forces invaded Finland with 21

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Weather conditions
The winter of 1939–40 was exceptionally cold with the Karelian Isthmus experiencing a record low temperature of −43 °C (−45 °F) on 16 January 1940. At the beginning of the war, only those Finnish soldiers who were in

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Soviet Air Force
The USSR enjoyed air superiority throughout the war. The Soviet Air Force, supporting the Red Army's

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Naval activity
There was little naval activity during the Winter War. The Baltic Sea began to freeze over by the end of December, impeding the movement of

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Red Army reforms and offensive preparations
Joseph Stalin was not pleased with the results of December in the Finnish campaign. The Red Army

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