Although Bolivia had lucrative mining income and a larger and better-equipped army, a series of factors turned the tide against it, and Paraguay controlled most of the disputed zone when the war had ended.

The origins of the war are commonly attributed to a long-standing territorial dispute and to the discovery of oil deposits on the eastern Andes range; in 1929, the Treaty of Lima ended the hopes of the Bolivian government of recovering a land corridor to the Pacific Ocean, which was thought imperative to further development and trade.

Indeed, both Paraguayan and Argentine planters were already breeding cattle and exploiting quebracho woods in the area,[20] and the small nomadic indigenous population of Guaraní-speaking tribes was related to Paraguay's own Guaraní heritage.

"[27] The first confrontation between the two countries dates back to 1885, when the Bolivian entrepreneur Miguel Araña Suárez founded Puerto Pacheco, a port on the Upper Paraguay River, south of Bahía Negra.

On 5 December 1928, a Paraguayan cavalry unit overran Fortin Vanguardia, an advance outpost established by the Bolivian army a few kilometres northwest of Bahía Negra.

A return to the status quo ante was eventually agreed on 12 September 1929 in Washington, DC, under pressure from the Pan American League, but an arms race had already begun, and both countries were on a collision course.

[35][36] After the commencement of hostilities, Paraguay captured sufficient numbers of Bolivian VZ-24 rifles and MP 28 submachine guns (nicknamed piripipi)[37] to equip all of its front-line infantry forces.

Furthermore, the typical Bolivian soldier was a Quechua or Aymara peasant conscript accustomed to life high in the Andes Mountains and did not fare well in the low-lying, hot, and humid land of the Chaco.

[41] In 1928, the British legation in La Paz reported to London that it took the Bolivian Army two weeks to march their men and supplies to the Chaco and that Bolivia's "inordinately long lines of communication" would help Paraguay if war broke out.

Hampered by the geography and difficult terrain of the Gran Chaco, combined with scarce water sources and inadequate logistical preparations, the Bolivian superiority in vehicles (water-cooled), tanks, and towed artillery did not prove decisive in the end.

Despite an international arms embargo imposed by the League of Nations, Bolivia in particular went to great lengths in trying to import a small number of Curtiss T-32 Condor II twin-engined bombers, disguised as civil transport planes, but they were stopped in Peru before they could be delivered.

[53] The Paraguayan Navy played a key role in the conflict by carrying thousands of troops and tons of supplies to the front lines via the Paraguay River, as well as by providing anti-aircraft support to transport ships and port facilities.

On 22 December 1932, three Bolivian Vickers Vespas attacked the Paraguayan riverine outpost of Bahía Negra, on the Paraguay River, and killed an army colonel, but one of the aircraft was shot down by the gunboat Tacuary.

[67] The 50-ton armed launch Tahuamanu, based in the Mamoré-Madeira fluvial system, was briefly transferred to Laguna Cáceres to ferry troops downriver from Puerto Suárez and challenged for eight months the Paraguayan naval presence in Bahía Negra.

[70] After the initial incident, Salamanca changed his status quo policy over the disputed area and ordered the outposts of Corrales, Toledo, and Fortín Boquerón to be captured.

On a memorandum directed to Salamanca on 30 August, Bolivian General Filiberto Osorio expressed his concerns over the lack of a plan of operations and attached one that focused on an offensive from the north.

Kundt had served intermittently as military advisor to Bolivia since the beginning of the century and had established good relationships with officers of the Bolivian Army and the country's political elites.

[72] In September, Paraguay began a new offensive in the form of three separate encirclement movements in the Alihuatá area, which was chosen since its Bolivian forces had been weakened by the transfer of soldiers to attack Fortín Gondra.

In February 1934, Emilio Sfeir—a Lebanese-Bolivian merchant residing in Jujuy, Argentina—masterminded the planning and execution of the capture, in Argentine territory, of Juan Valori, the most important Paraguayan spy of the Chaco War.[why?

The commander of the Paraguayan 3rd Corps, General Franco, found a gap between the Bolivian 1st and 18th Infantry regiments and ordered his troops to attack through it, but they became stuck in a salient with no hope of further progress.

Most of its indigenous soldiers lived on the cold Altiplano, at elevations of over 3,700 metres (12,000 ft), and they found themselves at a physical disadvantage when they were called upon to fight in tropical conditions at almost sea level.

However, the more valuable contribution to the Paraguayan cause came from Argentine military intelligence (G2), led by Colonel Esteban Vacareyza, which provided nightly reports on Bolivian movements and supply lines running along the border with Argentina.

[106] The greatest achievement of "San Martín" took place on 10 December 1933, when the First Squadron, led by Second Lieutenant Javier Gustavo Schreiber, ambushed and captured the two surviving Bolivian Vickers six-ton tanks on the Alihuatá-Savedra road during the Battle of Campo Vía.

In a speech on the Senate floor on 30 May 1934, Long, a radical populist, claimed the war was the work of "the forces of imperialistic finance" and maintained that Paraguay was the rightful owner of the Chaco but that Standard Oil, which Long called "promoter of revolutions in Central America, South America and Mexico," had "bought" the Bolivian government and started the war because Paraguay had been unwilling to grant it oil concessions.

[123] Very typical of the Spanish language histories was Marshal Estigarribia's remark in his memoirs: "But to this organized and arrogant power we intended to oppose the virile tradition of our people and the discipline of our courage" That for him was a sufficient explanation of Paraguay's victory.

Another diplomat and important figure of Bolivian literature, Adolfo Costa du Rels, wrote about the conflict, and his novel Laguna H3, published in 1938, was also set during the Chaco War.

[124] One of the masterpieces of the Paraguayan writer Augusto Roa Bastos, the 1960 novel Hijo de hombre, described in one of its chapters the carnage and harsh war conditions during the Siege of Boquerón.

[131] The Broken Ear, one of The Adventures of Tintin series of comic stories by the Belgian author Hergé (Georges Rémi), is set during a fictionalized account of the war between the invented nations of San Theodoros and Nuevo Rico.

In it, Doc Savage finds himself caught in the middle of two embattled South American republics (obviously Bolivia and Paraguay) that have found a new and deadly foe in the form of an evil hooded figure, known as The Inca in Gray.

When The Inca deploys a deadly "Dust of Death" to slaughter citizens on both sides of the fighting, Doc Savage and his team rush into the battle to try to save the day and to avoid the firing line.