Last day of the Battle of Boquerón between Paraguay and Bolivia during the Chaco War.

The Battle of Boquerón was fought September 9–29, 1932, between the Bolivian and Paraguayan armies in and around the stronghold of Boquerón. It was the first major battle of the Chaco War. The outpost (fortín) of Boquerón, among others, had been occupied by Bolivian troops since late July 1932 following instructions of president Daniel Salamanca, which led to the escalation of what began as a border conflict into a full-scale war. The Bolivian garrison was under the command of Colonel Manuel Marzana.