score:8
There are too many examples of this kind.
Secession of the USA from Great Britain
American civil war
Civil war in Russia in 1918-1922, particularly, secessions of Ukraine, Georgia and other territories.
Dessolution of the USSR, particularly secessions of the Baltic republics, as well as Russian SFSR itself.
Secession of Chechen republic from Russia.
Secession of Kosovo from Yugoslavia
Secessions of South Ossetia and Abkhazia from Georgia
Secession of Transdnistria from Moldova
Pretty much every anti-colonial war
Taiwan vs. China
and so on and so on.
Upvote:2
In 1984, an Austrian artist declared the Republic of Kugelmugel (about 8 m in diameter and situated right in the Austrian capital Vienna). He pulled a stunt by printing and publishing his own stamps and ran into expected and some unexpected troubles with various authorities accordingly. His republic was doomed as a sovereign entity among nations, but he ultimately received personal protection from being fined as he was seen as a likeable outsider (and perhaps of interest to the tourists also).