Pikysyry maneuver The so - called Pikysyry maneuver was a tactic used by Brazilian marshal Luís Alves de Lima e Silva , Duke of Caxias , during the Paraguayan War . It is considered the most daring and creative strategy of the entire conflict . History . After the fall of the Humaitá fortress in July 1868 , Francisco Solano López centered his troops in a strong position at the Pikysyry stream , which runs on the left margin of the Paraguay River . To circumvent it , Caxias decided to build an 11 - kilometer - long road on the right bank of the Paraguay River , passing through the Gran Chaco swamps , and leading to the Paraguayan rear . With the aid of the Brazilian Imperial Navy , Caxias carried 31 , 000 troops to the beginning of the road , from where they advanced along the right river bank , outflanking the enemy ' s fortified position . The Navy ships , after reaching Angostura pass , sailed north , where they re - embarked the troops from the road and carried them to the left bank in San Antonio , north of the enemy position . Paraguayan defense . Due to advancement Brazilian naval , President Lopez gave up defending the line Tebicuary River , installing a more defensive front near Asunción . After evaluating various positions , including Poí Estero , which drains the lake to the river Paraguay Ypoá , eventually organize a new defensive line , north of the creek Piquisiry , which was installed in early September 1868 . 15 The new position had several advantages On one hand , the attack from the south was to be made by ground troops crossed uninhabited floodplain , wooded and full of thorns . The second advantage was that at its west end , just north of the mouth of the creek Piquisiry in Paraguay , the river had a strong curve with a marked narrowing , dominated by high canyon , the " Angostura " . If they could outflank the defensive position , should face the broken landscape with steep hills Piquisiry there from north , on which they could build defenses , forcing the attackers to attack forces from the narrow streambeds that cross . The position had great against : the new battleground was no more than 35 km from the capital , Asunción , his fall , or enemy action signifying a rodeo in the same mean the fall of the capital . So Sanchez Vice President ordered the evacuation of Asuncion . The national government was installed from the February 22 , 1868 in the city of Luque , who - but close - not the banks of the Paraguay River . With the advance of Brazilians , the capital would be moved again on December 8 , this time to Piribebuy , much more to the east . By order of Lopez , the British engineer George Thompson raised a long line of fortifications between the Paraguay River waterfront and lagoon Ypoá . In practice , the line did not come this far east , but spread over 10 km . , To the marshes that extend to the east of the lagoon . Near the eastern boundary line , the hills of Ita Cumbarity Yvate and very close to each other and separated by a brook , Lopez Lomas Valentinas christened these , and they established their headquarters . The defensive line had 85 artillery pieces of various calibers more , plus 18 guns battery deployed in Angostura , one of the guns of the latter position was the huge " Criollo " , cast in casting Ybycuí , the piece largest artillery which had operated until then in South America . Although it took two months to raise the new fortification had no major problems doing that , because the Brazilian squad " slept on the glory of catching Humaitd " . North of the Paraguayan defensive position had a significant population , Villeta , which served as a supply center and port of the army . In early December , Lopez had 12 , 000 men for its defense , mostly teens and seniors Solano López , believing that the allied troops could not cross Chaco , was caught by surprise when the allied troops assaulted his rear , being forced to retreat with his surviving troops . This led to the battles of Itororó , Avaí and Lomas Valentinas .