Tacnazo insurrection (October 21, 1969) () was a brief revolt of the Tacna artillery regiment, led by General Roberto Viaux, in what turned out to be a non-violent demonstration against the government of Chilean President Eduardo Frei Montalva. Background Around mid-1969, Brigadier General Roberto Viaux, commander of the First Army Division stationed in Antofagasta, asked "the opinion of the young officers" (colonels, lieutenant colonels, majors, and captains) and based on their answers, wrote a letter of petition to the Army Commander-in-chief, General Sergio Castillo, to be presented to President Eduardo Frei Montalva. General Viaux's letter said that "national security and internal peace in our country" depended on the armed forces, and "in our judgement" the Frei administration, like its predecessors, had not concerned itself with keeping a modern army in working order, "well equipped and taking real part in important decisions". The letter demanded that a new government policy toward the armed forces be put into effect, that senior officers' salaries be adjusted to conform to "their high social status and national responsibility" (in the letter, Viaux complained that "a general of the Republic earns less than a competent worker at the Chuquicamata copper mine", which was true), that adequate materiel be purchased, and that the higher echelons of the military hierarchy be given a prominent participatory role in the economic, political, and social development of Chile. General Viaux was confident that his letter would lead to a new dialogue with President Frei, because he had discussed it beforehand with the head of the Army's General Staff, Division General René Schneider. The letter had even made suggestions about the "participatory" role of the generals in the economic and political life of the country. President Frei, however, did not listen to Schneider, but he did listen to Sergio Castillo, the commander in chief of the Army, an intimate personal friend and a political supporter above all else. Viaux was relieved of his command of the First Division on Saturday, October 18, 1969, and recalled to Santiago. Events On Tuesday, October 21, 1969, General Viaux became the head of a military insurrection localized in the Tacna Artillery Regiment in Santiago, with the support of the Sub-Officers' School, the Army War Academy, and part of the 2nd Armored Regiment. At noon on October 21, it was clear to the reporters covering the incident that General Viaux was counting on the covert support and