"Finland spent many years as part of Russian Empire"
Yes - and no. Legally Finland was a Grand Duchy, under the direct ownership of the Czar (who was the duke of Finland) - hence Finland was not actually part of the Russian state, even though it had the same head of state, but had parallel autonomous state functions.
At the end of 19th century Russian state started to abhor this autonomy, but actual dissolution of the independent state did not have time to take place before the Russian revolution. As czar died with no obvious inheritors, Finland guessed it was now independent and the Soviet state acknowledged it as such.
So Finland became independent from a luck of legalese basically, and the fact that Soviet state had other problems to deal with than a small parcel of land. The blood price for independence was paid later in civil war and in 2nd world war.
Yes - and no. Legally Finland was a Grand Duchy, under the direct ownership of the Czar (who was the duke of Finland) - hence Finland was not actually part of the Russian state, even though it had the same head of state, but had parallel autonomous state functions.
https://en.wikipedia.org/wiki/Grand_Duchy_of_Finland
At the end of 19th century Russian state started to abhor this autonomy, but actual dissolution of the independent state did not have time to take place before the Russian revolution. As czar died with no obvious inheritors, Finland guessed it was now independent and the Soviet state acknowledged it as such.
So Finland became independent from a luck of legalese basically, and the fact that Soviet state had other problems to deal with than a small parcel of land. The blood price for independence was paid later in civil war and in 2nd world war.