An amphibious operation was launched at Pisagua on November 2, pushing the Allies inland and obtaining an unshipping point to unload troops and material.

The string of victories made the Chilean commanders too confident, and with poor information recklessly attacked the outnumbering Peruvian army at Tarapacá on November 27, suffering a heavy defeat.

Once they had gained the Tarapacá department, the saltpetre trade earnings went directly to the Chilean government, making the war effort much easier by allowing the purchase of supplies needed for the growing army.

The loss of Tarapacá generated popular discontent in Peru and in Bolivia, resulting in the deposition of Mariano Ignacio Prado and Hilarión Daza, who were replaced by Nicolas de Pierola and General Narciso Campero.

With the Chilean domination of the sea so complete after the earlier battles, the Allies had no manoeuvre space for transporting huge contingents from north to south and vice versa.

The Chilean division was put under Lt. Col Arístides Martínez, and was formed by 500 men of the Lautaro Battalion and 12 riders of the Granaderos a Caballo Regiment.

The Peruvian forces had been gathered at Tacna and Arica, so in order to make a successful attack the entire Chilean army to a place near both cities, avoiding crossing the Atacama Desert.

On December 31, the Chilean troops disembarked and quickly took the port of Ilo, isolating Moquegua garrison of 1,300 soldiers and letting Martinez to move freely in the area, fulfilling the task commended.

The same day Baquedano occupied Moquegua while the first division of Montero's Southern Army under Col. Andres Gamarra withdrew to Los Angeles hill, seeking to assume a position easy to defend.

The Chilean army converged over the Sama river valley, set as a starting point to march across the desert towards Tacna, but the artillery was shipped to Ite.

The Allies didn't molested the Chilean march through the desert, due to internal disputes between Campero and Camacho and the lack of supplies and transportation lines.

[1] A last attempt to ambush the Chileans on the night of May 25 at Quebrada Honda failed,[3] because the darkness misled a column led by Campero, tiring his troops in vain.