Unification or Death ( Serbian : Уједињење или смрт , Ujedinjenje ili smrt ) , unofficially known as the Black Hand ( Црна рука , Crna ruka ) , was a secret military society formed on 6 September 1901 by members of the Serbian Army in the Kingdom of Serbia .
Black Hand or Crna Ruka , officially Ujedinjenje ili Smrt ( `` Unification or Death '' ) was a secret group of Serbian nationalists ( Pan-Serbians ) .