Combat Organization of the Polish Socialist Party

The Combat Organization of the Polish Socialist Party (Polish: Organizacja Bojowa Polskiej Partii Socjalistycznej, abbreviated OBPPS) was a Polish guerrilla resistance movement established in 1904 by Józef Piłsudski. It functioned as the paramilitary wing of the Polish Socialist Party.

Source: Wikipedia — Combat Organization of the Polish Socialist Party (CC BY-SA 4.0)