In Los Infantes captain Lorenzo Bernal del Mercado had discovered that the rebels had constructed a pukara close by, establishing a blockade of the city, additionally natives under the toqui Illangulién had chosen an impregnable position in a marsh.

In Los Infantes captain Lorenzo Bernal del Mercado had discovered that the rebels had constructed a pukara close by, establishing a blockade of the city.

Lorenzo Bernal ordered a reconnaissance patrol and he observed that the natives under the toqui Illangulién had chosen an impregnable position in a marsh and chose to retire.

Illangulién's troops then moved to a second position, nearer to Angol, to which captain Lorenzo Bernal responded with a new reconnaissance.

This time, seeing their dangerous proximity to Los Infantes, captain Bernal chose to attack the position before more Mapuches arrived.