The Thirtieth of September Movement (Indonesian: Gerakan 30 September, abbreviated as G30S, also known by the acronym Gestapu for Gerakan September Tiga Puluh, Thirtieth of September Movement) was a self-proclaimed organization of Indonesian National Armed Forces members who, in the early hours of 1 October 1965, assassinated six Indonesian Army generals in an abortive coup d'état, resulting in the unofficial but more accurate name of Gestok, for Gerakan Satu Oktober, or First of October Movement.
