Since 1862, politicians argued with the imperial government about the need to improve the border defenses of Mato Grosso and Rio Grande do Sul, which at that time were dangerously unguarded. Let s simulate what would be the best conditions for the Brazilian Expeditionary Force in the north of the Paraguay managed to complete the first phase of a strategic-military plan that aimed to establish a logistical base across the border on the Apa River. This would make it possible, in a second phase, to attempt to consolidate this axis of invasion and from there, an operational strategy could be pursued that would advance on Concepción and Asunción from the north, aiming to connect to the fluvial axis through the Paraguay River, from the Platinum region, south of the continent.