“... Earlier in the same year, Nazi Germany had staged the similar Gleiwitz incident to generate an excuse to withdraw from its nonaggression pact with Poland.[1] Also the Soviet war games held in March 1938 and 1939 had been based on a scenario where border incidents taking place at the village of Mainila would have sparked the war.
“Materials in the private archives of Soviet party leader Andrei Zhdanov show that the incident was orchestrated to paint Finland as an aggressor and launch an offensive.[6] The Finnish side denied responsibility for the attacks and identified Soviet artillery as their source—indeed, the war diaries of nearby Finnish artillery batteries show that Mainila was out of range of all of them, as they had been withdrawn to prevent such incidents.
“The Soviet Union then renounced the non-aggression pact with Finland and on 30 November 1939 launched the first offensives of the Winter War.”*
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https://en.wikipedia.org/wiki/Shelling_of_Mainila
*”A false flag operation is an act committed with the intent of disguising the actual source of responsibility and pinning blame on a second party. The term is popular amongst conspiracy theory promoters [analysts] in referring to covert operations of various governments and cabals.[1] ... The term today extends to include countries that organize attacks on themselves and make the attacks appear to be by enemy nations or terrorists, thus giving the nation that was supposedly attacked a pretext for domestic repression and foreign military aggression.”[7] ... https://en.wikipedia.org/wiki/False_flag