Soviet Shelling of Mainila: The Lie That Started the Winter War

Soviet artillery shells struck the village of Mainila near the Finnish border on November 26, 1939, killing four Red Army soldiers. Moscow blamed Finland and demanded that Finnish forces withdraw 25 kilometers from the border. Finland denied responsibility and proposed a joint investigation. The Soviet Union refused. Four days later, the Red Army invaded Finland. The shelling at Mainila was almost certainly staged by the Soviets themselves. Joseph Stalin had spent months pressuring Finland into territorial concessions. He wanted Finland to cede parts of the Karelian Isthmus to push Leningrad's border defenses further from the city, lease the Hanko Peninsula as a naval base, and cede several islands in the Gulf of Finland. The Finns negotiated but refused to surrender the Karelian Isthmus, their primary defensive line. Stalin needed a pretext for invasion, and the Mainila incident provided one. Finnish border guards recorded that the shells had been fired from the Soviet side. Nikita Khrushchev later confirmed in his memoirs that the shelling was a Soviet operation. The tactic followed a pattern: the Soviet Union had staged similar provocations against the Baltic states and Poland. The Mainila shelling gave Moscow diplomatic cover, however flimsy, to abrogate its non-aggression pact with Finland and launch what it framed as a defensive war. The invasion backfired spectacularly. The Red Army, weakened by Stalin's purges of its officer corps, expected to overrun Finland in weeks. Finnish forces inflicted devastating casualties through guerrilla tactics and fierce resistance in temperatures reaching minus 40 degrees. The Winter War lasted 105 days and cost the Soviet Union an estimated 125,000 dead. Finland ceded the demanded territory but preserved its independence. The Soviet performance was so poor that Hitler concluded the Red Army was weak, a miscalculation that contributed to his decision to invade the Soviet Union in 1941.