English: A defensive earthwork in the Paraguayan War, seen from the viewpoint of the attackers. From "Recuerdo de la Guerra del Paraguay" by José Ignacio Garmendia (1890: Buenos Aires). The caption translates as: "Point from which the Brazilians attacked, drawn at the scene six months after the assault".

With one exception (the Londres battery at Humaitá), all Paraguayan earthworks mounted artillery en barbette. A ditch was dug and the earth thrown behind to make a parapet. Artillery was moved out to fire grape or canister over the parapet and then retired for reloading. The oval shapes are powder-magazines made of sunbaked clay. The ditch is hidden behind the vegetation, but it gave the attackers an extra distance to climb. Infantry also fired muskets over the parapet; in case of enemy artillery fire they usually concealed themselves in another, shallow ditch at the rear (not shown).

With this simple earthwork defence the outnumbered Paraguayans repeatedly beat off attacks with little loss of lie to themselves and heavy loss of life to the enemy. This defence tactic was most unusual in South America where open, mobile warfare was the norm.

This particular earthwork is at Curupaty where the position had to be particularly strong, hence the number of powder-magazines.