The vz. 24 rifle is a bolt-action carbine designed and produced in Czechoslovakia from 1924 to 1942. It was developed from the German Mauser Gewehr 98 line, features a similar bolt design; the rifle was designed in Czechoslovakia shortly after World War I. 98/22 a Czech-designed derivative of the Gewehr 98. The vz. 24 featured a 590 mm barrel, shorter and considered more handy than the 740 mm Gewehr 98 barrel. The vz. 24 was chambered in 7.92×57mm Mauser like its predecessors. Throughout the late 1920s and into the 1930s, Czechoslovakia exported hundreds of thousands of vz. 24 rifles to various countries across the globe, with variants chambered in the original 7.92×57mm Mauser, 7×57mm Mauser, 7.65×53mm Argentine. These included contracts for several South American countries, most of which were 7 mm or 7.65 mm guns. Around 40,000 rifles were sent to Spanish Republican forces during the Spanish Civil War. Nearly 200,000 rifles were purchased by China, seeing action in the Second Sino-Japanese War, which became part of World War II.
Iran purchased vz. 24 rifles, along with two other variants, through the late 1920s and 1930s, produced their own copies in the late 1940s. Germany acquired hundreds of thousands of the rifles in 1939 when they occupied Czechoslovakia and pressed them into service under the designation "Gewehr 24". During this period, several hundred thousand rifles were built for the Romanian Army. Vz. 24 rifles saw extensive service during World War II in multiple theaters, predominantly with the German and Romanian armies on the Eastern Front. Lithuanian vz. 24s, captured during the German invasion in 1941, were seized by Soviet forces, who in turn used them to arm the Viet Cong during the Vietnam War in the 1960s. After World War I, the Austro-Hungarian Empire was dismantled; the new state received control of the Skoda factory in Brno, renamed the Brno Arms Works in November 1918. The following year, the factory began producing the first short rifles based on the German Gewehr 98 design, the Mauser Jelená.
At least 150 of the rifles were chambered in 7mm Mauser, with at least as many chambered in 7.92×57mm Mauser. The original Gewehr 98 rifle featured a barrel, 740 mm long, which proved to be too long and cumbersome in the trench fighting of World War I. Brno developed the long vz. 98/22 in 1922 from the basic Gewehr 98 design, with a 740 mm long barrel, along with a vz. 98/22 Short Rifle variant, though it did not see significant production. Starting in 1923, Brno decided to develop a rifle based on the German Karabiner 98AZ, a shortened version of the Gewehr 98 with a 590 mm barrel; this resulted in the vz. 23, a rifle with a 550 mm long barrel, produced with parts cannibalized from other rifles. The design was further refined into the vz. 23A, which consisted of newly manufactured components. Further refinements produced the vz. 24, which entered production in 1924. That year, Brno Arms Works, controlled by the Czechoslovak government, was privatized to encourage export sales; the vz.24 became the primary rifle of the Czechoslovak Army before World War II.
It resembled the German Karabiner 98k. Unlike the K98k, the vz. 24 has a longer top handguard, it retains a straight bolt handle. Between 1924 and 1938, Czechoslovakia manufactured more than 775,600 rifles, with the first rifles entering service in 1926; the final order was placed in July 1938, as tensions escalated with Nazi Germany over the Sudeten Germans. Following the German occupation of Czechoslovakia, production continued for the Slovak Republic; the exact number of rifles manufactured between 1938 and 1939 is unknown, but may be less than 10,000, based on serial numbers of surviving rifles. The vz. 24 was a bolt action design based on the Mauser action, featuring a straight bolt handle. The rifle's barrel, 590 millimeters long, featured 4-groove rifling with a right-hand twist. Overall, the rifle was 1,100 mm long, it weighed 4.2 kilograms. The primary chambering was for 7.92×57mm Mauser, but export variants were chambered for 7×57mm Mauser and 7.65×53mm Argentine. Ammunition was stored in a five-round, internal magazine that fit flush with the bottom of the stock, fed with stripper clips.
The rifles were fitted with tangent rear sights that were graduated in 50-meter increments, up to a maximum range of 2,000 m. The front sight blade was fitted with a protector to prevent it from being damaged; the rifle's stock featured a pistol grip and an upper hand guard that extended from the forward receiver ring to the forward barrel band. Sling swivels were placed on the bottom rear of the butt and the left side of the grip and on the rear barrel band. Grasping grooves were placed just forward of the recoil lug to aid in handling the rifle. A cleaning rod was stored in the stock under the barrel. Many South American countries purchased the vz. 24 rifle in various calibers. Between 1928 and 1938, the Bolivian Army purchased 101,000 vz. 24 rifles, which were chambered in 7.65×53mm Argentine. These rifles were used against Paraguay during the Chaco War in the 1930s, many of them were captured by the Paraguayan Army, which in turn used them against Bolivia. Colombia ordered 10,000 rifles between 1929 and 1937 and Venezuela purchased an unknown number of rifles in 1930.
In 1932, Brazil
Ecuador the Republic of Ecuador, is a country in northwestern South America, bordered by Colombia on the north, Peru on the east and south, the Pacific Ocean to the west. Ecuador includes the Galápagos Islands in the Pacific, about 1,000 kilometres west of the mainland; the capital city is Quito, the largest city. What is now Ecuador was home to a variety of Amerindian groups that were incorporated into the Inca Empire during the 15th century; the territory was colonized by Spain during the 16th century, achieving independence in 1820 as part of Gran Colombia, from which it emerged as its own sovereign state in 1830. The legacy of both empires is reflected in Ecuador's ethnically diverse population, with most of its 16.4 million people being mestizos, followed by large minorities of European and African descendants. Spanish is the official language and is spoken by a majority of the population, though 13 Amerindian languages are recognized, including Quichua and Shuar; the sovereign state of Ecuador is a middle-income representative democratic republic with a developing economy, dependent on commodities, namely petroleum and agricultural products.
It is governed as a democratic presidential republic. One of 18 megadiverse countries in the world, Ecuador hosts many endemic plants and animals, such as those of the Galápagos Islands. In recognition of its unique ecological heritage, the new constitution of 2008 is the first in the world to recognize enforceable Rights of Nature, or ecosystem rights, it has the fifth lowest homicide rate in the Americas. Various peoples had settled in the area of the future Ecuador before the arrival of the Incas; the archeological evidence suggests that the Paleo-Indians' first dispersal into the Americas occurred near the end of the last glacial period, around 16,500–13,000 years ago. The first Indians who reached Ecuador may have journeyed by land from North and Central America or by boat down the Pacific Ocean coastline. Much migrations to Ecuador may have come via the Amazon tributaries, others descended from northern South America, others ascended from the southern part of South America through the Andes.
They developed different languages while emerging as unique ethnic groups. Though their languages were unrelated, these groups developed similar groups of cultures, each based in different environments; the people of the coast developed a fishing and gathering culture. Over time these groups began to interact and intermingle with each other so that groups of families in one area became one community or tribe, with a similar language and culture. Many civilizations arose in Ecuador, such as the Valdivia Culture and Machalilla Culture on the coast, the Quitus, the Cañari; each civilization developed its own distinctive architecture and religious interests. In the highland Andes mountains, where life was more sedentary, groups of tribes cooperated and formed villages. Through wars and marriage alliances of their leaders, a group of nations formed confederations. One region consolidated under a confederation called the Shyris, which exercised organized trading and bartering between the different regions.
Its political and military power came under the rule of the Duchicela blood-line. When the Incas arrived, they found that these confederations were so developed that it took the Incas two generations of rulers—Topa Inca Yupanqui and Huayna Capac—to absorb them into the Inca Empire; the native confederations that gave them the most problems were deported to distant areas of Peru and north Argentina. A number of loyal Inca subjects from Peru and Bolivia were brought to Ecuador to prevent rebellion. Thus, the region of highland Ecuador became part of the Inca Empire in 1463 sharing the same language. In contrast, when the Incas made incursions into coastal Ecuador and the eastern Amazon jungles of Ecuador, they found both the environment and indigenous people more hostile. Moreover, when the Incas tried to subdue them, these indigenous people withdrew to the interior and resorted to guerrilla tactics; as a result, Inca expansion into the Amazon Basin and the Pacific coast of Ecuador was hampered.
The indigenous people of the Amazon jungle and coastal Ecuador remained autonomous until the Spanish soldiers and missionaries arrived in force. The Amazonian people and the Cayapas of Coastal Ecuador were the only groups to resist Inca and Spanish domination, maintaining their language and culture well into the 21st century. Before the arrival of the Spaniards, the Inca Empire was involved in a civil war; the untimely death of both the heir Ninan Cuchi and the Emperor Huayna Capac, from a European disease that spread into Ecuador, created a power vacuum between two factions. The northern faction headed by Atahualpa claims that Huayna Capac gave a verbal decree before his death about how the empire should be divided, he gave the territories pertaining to present-day Ecuador and northern Peru to his favorite son Atahualpa, to rule from Quito. He willed that his heart be buried in Quito, his favorite city, the rest of his body be buried with his ancestors in Cuzco. Huáscar did not recognize his fa
World War II
World War II known as the Second World War, was a global war that lasted from 1939 to 1945. The vast majority of the world's countries—including all the great powers—eventually formed two opposing military alliances: the Allies and the Axis. A state of total war emerged, directly involving more than 100 million people from over 30 countries; the major participants threw their entire economic and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources. World War II was the deadliest conflict in human history, marked by 50 to 85 million fatalities, most of whom were civilians in the Soviet Union and China, it included massacres, the genocide of the Holocaust, strategic bombing, premeditated death from starvation and disease, the only use of nuclear weapons in war. Japan, which aimed to dominate Asia and the Pacific, was at war with China by 1937, though neither side had declared war on the other. World War II is said to have begun on 1 September 1939, with the invasion of Poland by Germany and subsequent declarations of war on Germany by France and the United Kingdom.
From late 1939 to early 1941, in a series of campaigns and treaties, Germany conquered or controlled much of continental Europe, formed the Axis alliance with Italy and Japan. Under the Molotov–Ribbentrop Pact of August 1939, Germany and the Soviet Union partitioned and annexed territories of their European neighbours, Finland and the Baltic states. Following the onset of campaigns in North Africa and East Africa, the fall of France in mid 1940, the war continued between the European Axis powers and the British Empire. War in the Balkans, the aerial Battle of Britain, the Blitz, the long Battle of the Atlantic followed. On 22 June 1941, the European Axis powers launched an invasion of the Soviet Union, opening the largest land theatre of war in history; this Eastern Front trapped most crucially the German Wehrmacht, into a war of attrition. In December 1941, Japan launched a surprise attack on the United States as well as European colonies in the Pacific. Following an immediate U. S. declaration of war against Japan, supported by one from Great Britain, the European Axis powers declared war on the U.
S. in solidarity with their Japanese ally. Rapid Japanese conquests over much of the Western Pacific ensued, perceived by many in Asia as liberation from Western dominance and resulting in the support of several armies from defeated territories; the Axis advance in the Pacific halted in 1942. Key setbacks in 1943, which included a series of German defeats on the Eastern Front, the Allied invasions of Sicily and Italy, Allied victories in the Pacific, cost the Axis its initiative and forced it into strategic retreat on all fronts. In 1944, the Western Allies invaded German-occupied France, while the Soviet Union regained its territorial losses and turned toward Germany and its allies. During 1944 and 1945 the Japanese suffered major reverses in mainland Asia in Central China, South China and Burma, while the Allies crippled the Japanese Navy and captured key Western Pacific islands; the war in Europe concluded with an invasion of Germany by the Western Allies and the Soviet Union, culminating in the capture of Berlin by Soviet troops, the suicide of Adolf Hitler and the German unconditional surrender on 8 May 1945.
Following the Potsdam Declaration by the Allies on 26 July 1945 and the refusal of Japan to surrender under its terms, the United States dropped atomic bombs on the Japanese cities of Hiroshima and Nagasaki on 6 and 9 August respectively. With an invasion of the Japanese archipelago imminent, the possibility of additional atomic bombings, the Soviet entry into the war against Japan and its invasion of Manchuria, Japan announced its intention to surrender on 15 August 1945, cementing total victory in Asia for the Allies. Tribunals were set up by fiat by the Allies and war crimes trials were conducted in the wake of the war both against the Germans and the Japanese. World War II changed the political social structure of the globe; the United Nations was established to foster international co-operation and prevent future conflicts. The Soviet Union and United States emerged as rival superpowers, setting the stage for the nearly half-century long Cold War. In the wake of European devastation, the influence of its great powers waned, triggering the decolonisation of Africa and Asia.
Most countries whose industries had been damaged moved towards economic expansion. Political integration in Europe, emerged as an effort to end pre-war enmities and create a common identity; the start of the war in Europe is held to be 1 September 1939, beginning with the German invasion of Poland. The dates for the beginning of war in the Pacific include the start of the Second Sino-Japanese War on 7 July 1937, or the Japanese invasion of Manchuria on 19 September 1931. Others follow the British historian A. J. P. Taylor, who held that the Sino-Japanese War and war in Europe and its colonies occurred and the two wars merged in 1941; this article uses the conventional dating. Other starting dates sometimes used for World War II include the Italian invasion of Abyssinia on 3 October 1935; the British historian Antony Beevor views the beginning of World War II as the Battles of Khalkhin Gol fought between Japan and the fo
A machine gun is a automatic mounted or portable firearm designed to fire rifle cartridges in rapid succession from an ammunition belt or magazine for the purpose of suppressive fire. Not all automatic firearms are machine guns. Submachine guns, assault rifles, battle rifles, pistols or cannons may be capable of automatic fire, but are not designed for sustained fire; as a class of military rapid-fire guns, machine guns are automatic weapons designed to be used as support weapons and used when attached to a mount- or fired from the ground on a bipod or tripod. Many machine guns use belt feeding and open bolt operation, features not found on rifles. In the U. S. A, a "machine gun" is a legal term for any weapon able to fire more than one shot per function of the trigger regardless of caliber, the receiver of any such weapon, any weapon convertible to such a state using normal tools, or any component or part that will modify an existing firearm such that it functions as a "machine gun" such as a drop-in auto sear.
Civilian possession of such weapons manufactured prior to 1986 is not prohibited by any federal law and not illegal in many states, but they must be registered as Title II weapons under the National Firearms Act and have a tax stamp paid. Machine guns manufactured after 1986 are prohibited by the Hughes Amendment to the Gun Owners Protection Act. Unlike semi-automatic firearms, which require one trigger pull per round fired, a machine gun is designed to fire for as long as the trigger is held down. Nowadays the term is restricted to heavy weapons, able to provide continuous or frequent bursts of automatic fire for as long as ammunition lasts. Machine guns are used against personnel and light vehicles, or to provide suppressive fire, either directly or indirectly, they are mounted on fast attack vehicles such as technicals to provide heavy mobile firepower, armored vehicles such as tanks for engaging targets too small to justify use of the primary weaponry or too fast to engage with it, on aircraft as defensive armament or for strafing ground targets, though on fighter aircraft true machine guns have been supplanted by large-caliber rotary guns.
Some machine guns have in practice sustained fire continuously for hours. Because they become hot all machine guns fire from an open bolt, to permit air cooling from the breech between bursts, they usually have either a barrel cooling system, slow-heating heavyweight barrel, or removable barrels which allow a hot barrel to be replaced. Although subdivided into "light", "medium", "heavy" or "general-purpose" the lightest machine guns tend to be larger and heavier than standard infantry arms. Medium and heavy machine guns are either mounted on a vehicle. Light machine guns are designed to provide mobile fire support to a squad and are air-cooled weapons fitted with a box magazine or drum and a bipod. Medium machine guns use full-sized rifle rounds and are designed to be used from fixed positions mounted on a tripod. Heavy machine gun is a term originating in World War I to describe heavyweight medium machine guns and persisted into World War II with Japanese Hotchkiss M1914 clones. A general-purpose machine gun is a lightweight medium machine gun which can either be used with a bipod and drum in the light machine gun role or a tripod and belt feed in the medium machine gun role.
Machine guns have simple iron sights, though the use of optics is becoming more common. A common aiming system for direct fire is to alternate solid rounds and tracer ammunition rounds, so shooters can see the trajectory and "walk" the fire into the target, direct the fire of other soldiers. Many heavy machine guns, such as the Browning M2.50 caliber machine gun, are accurate enough to engage targets at great distances. During the Vietnam War, Carlos Hathcock set the record for a long-distance shot at 7,382 ft with a.50 caliber heavy machine gun he had equipped with a telescopic sight. This led to the introduction of.50 caliber anti-materiel sniper rifles, such as the Barrett M82. Other automatic weapons are subdivided into several categories based on the size of the bullet used, whether the cartridge is fired from a closed bolt or an open bolt, whether the action used is locked or is some form of blowback. Automatic firearms using pistol-calibre ammunition are called machine pistols or submachine guns on the basis of size.
The term personal defense weapon is sometimes applied to weapons firing dedicated armor-piercing rounds which would otherwise be regarded as machine pistols or SMGs, but it is not strongly defined and has been used to describe a range of weapons from ordinary SMGs to compact assault rifles. Selective fire rifles firing a full-power rifle cartridge from a closed bolt are called automatic rifles or battle rifles, while rifles that fire an intermediate cartridge are called assault rifles. Assault rifles are a compromise between the size and weight of a pistol-calibre submachine gun and a full size battle rifle, firing intermediate cartridges and allowing semi-automatic and burst or full-automatic fire options
In firearms and artillery, the primer is the chemical and/or device responsible for initiating the propellant combustion that will push the projectiles out of the gun barrel. In early, black powder guns such as muzzleloaders, the primer was the same chemical as the main propellant, but poured into an external flash pan, where it could be ignited by an ignition source such as a slow match or a flintlock; this external powder was connected through a small opening at the rear of the gun barrel that led to the main charge within the barrel. As gunpowder will not burn when wet, this made it difficult to fire these types of weapons in rainy or humid conditions. Modern primers, by contrast, are more specialized and distinct from the main propellant they are designed to ignite, they are of two types, those using shock-sensitive chemicals, those reliant on chemicals ignited by an electric impulse. In smaller weapons the primer is of the first type and integrated into the base of a cartridge. Examples include handgun cartridges, rifle cartridges and shotgun shells.
Larger artillery pieces in contrast use electric priming. In artillery the primers are a separate component, placed inside the barrel to the rear of the main propellant charge -- but there are other examples of guns, including for example some automatic weapons, designed to shoot cartridges with integral electric primers. Upon being struck with sufficient force generated by the firing pin, or electrically ignited, primers react chemically to produce heat, which gets transferred to the main propellant charge and ignites it, this, in turn, propels the projectile. Due to their small size, these primers themselves lack the power to shoot the projectile, but still have enough energy to drive a bullet partway into the barrel — a dangerous condition called a squib load; the first step to firing a firearm of any sort is igniting the propellant. The earliest firearms were hand cannons. There was a small aperture, the "touchhole", drilled in the closed end of the tube, leading to the main powder charge.
This hole was filled with finely ground powder, ignited with a hot ember or torch. With the advent of hand-held firearms, this became an undesirable way of firing a gun. Holding a burning stick while trying to pour a charge of black powder down a barrel is dangerous, trying to hold the gun with one hand while aiming at the target and looking for the touchhole makes it difficult to fire accurately; the first attempt to make the process of firing a small arm easier was the "matchlock". The matchlock incorporated a "lock", actuated by a trigger called a "tricker." The lock was a simple lever which pivoted when lowered the match down to the touchhole. The match was a slow-burning fuse made of plant fibers that were soaked in a solution of nitrates and sulfur, dried; this "slow-match" was ignited before the gun was needed, it would burn, keeping a hot ember at the burning end. After the gun was loaded and the touchhole primed with powder, the burning tip of the match was positioned so that the lock would bring it into contact with the touchhole.
To fire the gun, it was aimed and the trigger pulled. This brought the match down to the touchhole. With careful attention, the slow-burning match could be kept burning for long periods of time, the use of the lock mechanism made accurate fire possible; the next revolution in ignition technology was the "wheel-lock". It used a spring-loaded, serrated steel wheel which rubbed against a piece of iron pyrite, similar to a modern lighter. A key was used to put the spring under tension. Once tensioned, the wheel was held in place by a trigger; when the trigger was pulled, the serrated edge of the steel rubbed against the pyrite, generating sparks. These sparks were directed into a pan, called the "flash pan", filled with loose powder which led into the touchhole; the flashpan was protected by a spring-loaded cover that would slide out of the way when the trigger was pulled, exposing the powder to the sparks. The wheel-lock was a major innovation — since it did not rely on burning material as a source of heat, it could be kept ready for extended periods of time.
The covered flashpan provided some ability to withstand bad weather. Wind and wet weather would render a matchlock useless, but a wheel-lock, loaded and waterproofed with a bit of grease around the flashpan could be fired under most conditions; the wheel-lock enjoyed only a brief period of popularity before being superseded by a simpler, more robust design. The "flintlock", like the wheel-lock, used a spark to ignite the powder; as the name implies, the flintlock used flint rather than iron pyrite. The flint was held in a spring-loaded arm, called the "cock" from the resemblance of its motion to a pecking chicken; the cock rotated through a 90-degree arc and was held in the tensioned, or "cocked" position by a trigger. Flintlocks could lock the cock in two positions; the "half-cock" position held the cock halfway back, used a deep notch so that pulling the trigger would not release the cock. Half-cock was a safety position, used when storing or carrying a loaded flintlock; the "full-cock" position held the cock all the way back and was the position from which the gun was fired.
The L-shaped "frizzen" was the other half of the flintlock's ignition system. It served as both a steel striking surface for the flint; the frizzen was hinged and spring-loaded so that it would lock in the open or clos
The Chaco War was fought between Bolivia and Paraguay over control of the northern part of the Gran Chaco region of South America, thought to be rich in oil. It is referred to as La Guerra de la Sed in literary circles, for being fought in the semi-arid Chaco, it was the bloodiest military conflict fought in South America during the 20th century, between two of its poorest countries, both having lost territory to neighbors in 19th-century wars. During the war, both landlocked countries faced difficulties shipping arms and supplies through neighboring countries. Bolivia faced particular external trade problems, coupled with poor internal communications. Although Bolivia had lucrative mining income and a larger, better-equipped army, a series of factors turned the tide against it, Paraguay came to control most of the disputed zone by war's end; the ultimate peace treaties granted two-thirds of the disputed territories to Paraguay. The origin of the war is attributed to a long-standing territorial dispute and the discovery of oil deposits on the Andean plains.
In 1929, the Treaty of Lima ended the hopes of the Bolivian government of recovering a land corridor to the Pacific Ocean, thought imperative to further development and trade. The impetus for war was exacerbated by a conflict between oil companies jockeying for exploration and drilling rights, with Royal Dutch Shell backing Paraguay and Standard Oil supporting Bolivia; the discovery of oil in the Andean foothills sparked speculation that the Chaco might prove a rich source of petroleum, foreign oil companies were involved in the exploration. Standard Oil was producing oil from wells in the high hills of eastern Bolivia, around Villa Montes. However, it is uncertain if the war would have been caused by the interests of these companies, not by aims of Argentina to import oil from the Chaco. In opposition to the "dependency theory" of the war's origins, the British historian Matthew Hughes argued against the thesis that Bolivian and Paraguayan governments were the "puppets" of Standard Oil and Royal Dutch Shell writing: "In fact, there is little hard evidence available in the company and government archives to support the theory that oil companies had anything to do with causing the war or helping one side or the other during the war".
Both Bolivia and Paraguay were landlocked. Though the 600,000 km2 Chaco was sparsely populated, control of the Paraguay River running through it provided access to the Atlantic Ocean; this became important to Bolivia, which had lost its Pacific coast to Chile in the 1879 War of the Pacific. Paraguay had lost half of its territory to Brazil and Argentina in the Paraguayan War of 1864–1870; the country was not prepared to surrender its economic viability. In international arbitration, Bolivia argued that the region had been part of the original Spanish colonial province of Moxos and Chiquitos to which Bolivia was heir. Meanwhile, Paraguay based its case on the occupation of the land. Indeed, both Paraguayan and Argentine planters were breeding cattle and exploiting quebracho woods in the area, while the small nomadic indigenous population of Guaraní-speaking tribes was related to Paraguay's own Guaraní heritage; as of 1919, Argentine banks owned 400,000 hectares of land in the eastern Chaco while the Casado family, a powerful part of the Argentine oligarchy, held 141,000.
The presence of Mennonite colonies in the Chaco, who settled there in the 1920s under the auspices of the Paraguayan parliament, was another factor in favour of Paraguay's claim. 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, he assumed that the new settlement was well inside Bolivian territory, but Bolivia had implicitly recognized Bahía Negra as Paraguayan. The Paraguayan government sent in a naval detachment aboard the gunboat Pirapó, which forcibly evicted the Bolivians from the area in 1888. Two agreements followed—in 1894 and 1907—which neither the Bolivian nor the Paraguayan parliament approved. Meanwhile, in 1905 Bolivia founded two new outposts in the Chaco, Ballivián and Guachalla, this time along the Pilcomayo River; the Bolivian government ignored the half-hearted Paraguayan official protest. Bolivian penetration in the region went unopposed until 1927, when the first blood was shed over the Chaco Boreal.
On 27 February a Paraguayan army foot patrol and its native guides were taken prisoners near the Pilcomayo River and held in the Bolivian outpost of Fortin Sorpresa, where the commander of the Paraguayan platoon, lieutenant Adolfo Rojas Silva, was shot and killed in suspicious circumstances. Fortín was the name used for the small pillbox and trench-like garrisons in the Chaco, although the troops' barracks were no more than a few mud huts. While the Bolivian government formally regretted the death of Rojas Silva, the Paraguayan public opinion called it "murder". After the subsequent talks arranged in Buenos Aires failed to produce any agreement and collapsed in January 1928, the dispute grew violent. On 5 December 1928 a Paraguayan cavalry unit overran Fortin Vanguardia, an advance outpost established by the Bolivian army a few miles northwest of Bahía Negra; the Paraguayans burnt the scattered huts to the ground. The Bolivians retaliated with an air strike on Bahía Negra on 15 December, which caused few casualties and not much damage.
On 14 December Bolivia seized Fortin Boquerón, which would be the site of the first major battle of the campaign