One Year War

The One Year War (一年戦争, Ichinen Sensō) was the first major conflict of the Universal Century timeline, fought between the Principality of Zeon and the Earth Federation from January 3, 0079 to January 1, 0080. Mobile Suit Gundam, 08th MS Team, and 0080 War in the Pocket all take place during the One Year War.

Causes
The One Year War was a culmination of the hostility between Side 3's Principality of Zeon and the Earth Federation. Relations between the two had been tense since Side 3 declared themselves the independent Republic of Zeon under the leadership of Zeon Zum Deikun in UC 0058, and had only worsened since Deikun's death and the Zabi family's rise to power in UC 0068. Declaring themselves the Principality of Zeon a year later, and brutally purging Zeon Deikun's remaining followers, the Principality became increasingly hostile to the Earth Federation. In October of UC 0078, the Zeon entered a state of national mobilization, dividing their military into a Space Attack Force under the command of Dozle Zabi and a Mobile Assault Force under the command of Kycilia Zabi. Three months later, in January UC 0079, the Principality of Zeon declared open war on the Earth Federation.

Overview
The One Year War was the single largest and most devastating conflict of the Universal Century, in both the number of military casualties, civilian deaths, and devastation across the entire Earth Sphere. It began on January 3, UC 0079, when the Principality of Zeon launched surprise attacks against the Earth Federation controlled Sides. During the fierce fighting of the first month of the war, weapons of mass destruction were used indiscriminately, with Zeon forces deploying G3 Gas in inhabited colonies, attempting a colony drop against the EFF's headquarters at Jaburo during Operation British, and both sides using nuclear weapons during the Battle of Loum. During this period of fighting, each side lost nearly half of their respective populations. After this, both parties agreed to sign the Antarctic Treaty which, among other things, forbid the use of weapons of mass destruction.

With the Earth Federation Space Forces devastated, Zeon pressed its advantage by staging an invasion of Earth, dropping mobile suit forces onto the planet during several operations in March of UC 0079. This began a long stalemate period between the Earth Federation and the Principality of Zeon, with the Earth Federation slowly giving ground until the Zeon had control over approximately two thirds of Earth's surface. In September, the Earth Federation's Operation V was scheduled to undergo secret testing in Side 7, but was discovered by Zeon forces under the command of Char Aznable. This marks the beginning of the events of Mobile Suit Gundam.

The turning point of the war was in early November, when the Earth Federation launched Operation Odessa, a counteroffensive against Zeon forces in eastern Europe. Using almost entirely conventional forces, the Earth Federation was victorious, successfully defeating the Zeon, forcing much of their force to retreat or surrender. Soon after, the Earth Federation launched its counteroffensive into space, attacking first the Zeon Space Attack Force headquarters at the Solomon asteroid base on Christmas Eve, December 24, and then defeating the Zeon forces gathered at A Baoa Qu on New Year's Eve, December 31. After Zeon's defeat at A Baoa Qu, Zeon officially surrendered, ending the war on January 1, UC 0080.

The One Week Battle
The Principality of Zeon launched a surprise attack against Side 1, Side 2, and Side 4 on January 3, UC 0079. Attacking a mere three seconds after officially declaring war (a fact that was sardonically referred to as the "three second warning"), the Zeon used their mobile suit forces to eliminate Earth Federation Space Forces resistance before killing the civilian inhabitants of a number of colonies with poison gas. In this manner, an approximately unknown amount of Spacenoids were killed by Zeon forces. This period of initial slaughter became known as the One Week Battle or One Week War. It was during this time that Side 6 declared its neutrality in the conflict.

The peak of the One Week Battle was Operation British, which took place on January 10, UC 0079. Zeon forces used the depopulated colony cylinder Side 2, Bunch 8 Island Iffish in an attempt to destroy the Earth Federation Forces main headquarters, Jaburo. Though the Earth Federation Space Forces dispatched a fleet of their surviving warships in an attempt to stop the operation, the Zeon military successfully defended the colony and the EFSF was forced to withdraw after taking near total losses. Upon entering the atmosphere, however, Isle Iffish broke apart, missing Jaburo but causing widespread destruction across Earth. The largest remaining piece of the colony, consisting of approximately the entire front half, hit Sydney, Australia, completely wiping out the city and causing massive damage across the entire continent.

The Battle of Loum
After the failure of Operation British, Zeon forces attacked Side 5, also known as Loum, on January 15, UC 0079. Beginning as an attempt to drop a second colony, the operation quickly turned into a full scale fleet battle when the majority of the surviving Earth Federation Space Forces, commanded by General Revil, counterattacked. Both sides used nuclear weapons in this battle, causing horrific loss of life not only among the combatants, but resulting in complete destruction of Side 5 as well. The Earth Federation managed to halt the attempted colony drop and inflict significant losses on the Zeon, but they were unable to prevent the destruction of Side 5 but they were able to evacuate few million of it's inhabitants before the battle begin, and their forces were annihilated during the battle. The Battle of Loum marks the first time that mobile suits showed their true potential in combat, proving to be viciously effective against the Earth Federation fleet. General Revil was captured by the Black Tri-Stars, and several other Zeon aces (most notably Char Aznable, Shin Matsunaga, and Johnny Ridden) first made a name for themselves during the battle.

During the Battle of Loum, the Zeon 603 Technical Evaluation Division set up and deployed a massive cannon, the QCX-76A Jormungand. The special forces operatives who were in charge of the cannon had high hopes that the Jormungand would be the weapon, with its immense firepower and tremendous firing range, that gave Zeon the edge it needed to win. However despite the fact that Jormungand's operators were ordered into position for the battle they were never given the needed targeting data, and in fact it appeared that Zeon command never had any intention of using the weapon, instead relying on the new MS-06 Zaku II. The Jormungand's gunner did fire three shots using visual data and managed to destroy one Magellan-class battleship, and possibly disabled one Salamis-class cruiser.

The Antarctic Treaty
After the atrocities of the One Week Battle and the Battle of Loum, with nearly one third of humanity dead, the Earth Federation and the Principality of Zeon met in Antarctica to discuss terms of peace. The Earth Federation, having suffered major losses to its space forces at Loum as well as the loss of more than one billion of its citizens in less than a month, were ready to consider surrendering to the Principality of Zeon. However, during the negotiations, General Revil escaped from Zeon custody and returned to the Earth Federation, giving his famous "Zeon is exhausted!" speech detailing the poor condition of Zeon's military after the heavy fighting. In a large part due to this speech, the Earth Federation refused to surrender at Antarctica, instead negotiating for several important agreements. The use of weapons of mass destruction -- including the use of nuclear and chemical weapons, as well as colony drops -- were declared forbidden, rules for the humane treatment of POWs were agreed upon, and the neutrality of uninvolved parties such as Side 6 and the Jupiter Energy Fleet were guaranteed.

The Earth Invasion
Following the bloody One Week War, the Federation and Principality signed the Antarctic Treaty, forbidding the use of Nuclear, Biological, and Chemical (NBC) weapons. While this narrowed the range of strategic options, it also gave a distinct advantage to the Principality Army, whose plans were centered on use of Mobile Suits. Upon realizing that the war was becoming a long, drawn out battle instead of a sudden, quick strike, the Principality of Zeon decided to invade Earth. One week later, the Principality commenced its assault on Earth itself, using the Mass Driver, an electromagnetic "catapult" on the lunar surface, to send their MS into space and Earth. In February they began to organize an Earth Attack Force under the command of Garma Zabi, the youngest member of the Zabi family, divided into five MS divisions with distinct goals. Beginning on March 1, the newly formed Earth Attack Force began staging drop operations to land troops on Earth; over the course of the next month, they would stage a total of five drops, landing in central Asia, North America, Australia, and northern African and the Middle East.

The first group dropped on Central Asia, wiping out the Federation's Baikonur spaceport. They then advanced to the Caspian Sea, moving west into Europe and south into the Middle East. The second and third groups were dropped on both coasts of North America with two objectives: 1) To subjugate the Federation's industrial military complex. 2) To take over the Federation food supply. The California Base (a generic term for the more than 20 military bases along the west coast) became the staging ground for subsequent terrestrial assaults. As the bases were captured without damage, they were soon converted to production on Zeon MS. The fourth group, aided by support troops already on Earth, occupied many islands of the oceania region for the procurement of resources. Up until then, the Principality faced a distinct disadvantage in resource availability, having to rely on Lunar and asteroid mining. The fifth and final group landed in the largely unprotected deserts of North Africa. With facilities, food and resources at their disposal, the Principality was set for global conquest.

From these drop locations, the Zeon army spread across the planet, using captured facilities and material (notably including the Earth Federation's massive California Base) to strengthen their military power. Within a few months, Zeon controlled most of Europe, Asia and North America. With the Federation forces scattered and their numbers decimated, their outlook was grim.

Operation V
During Zeon's offensive on Earth, the Earth Federation were desperately trying to develop mobile suits of their own. Project V was a result of this; a top secret Earth Federation Forces research project aimed at producing mobile suits for the Earth Federation, while the Vison Plan was enacted to rebuild the Earth Federation Space Forces. A major breakthrough of Project V was the development of compact, mobile suit-sized beam weapons, giving a mobile suit the effective power of a battleship cannon. Three prototype designs were completed under Operation V; the long-range tank-like RX-75 Guntank, the mid-range support RX-77 Guncannon, and the close combat oriented RX-78-2 Gundam. The suits would be stored on the Federation's newest battleship, the SCV-70 White Base, the first Federation warship to not only carry mobile suits, but also able to operate on Earth and in space. Unfortunately for the Earth Federation, while the new Pegasus-class ship White Base was traveling to Side 7 with a number of RX-series prototypes for space testing, they were discovered by a Zeon Musai commanded by Char Aznable. Aznable's subordinates attempted to destroy the Operation V prototypes while on a recon mission inside Side 7, and during the attack the civilian Amuro Ray managed to enter the cockpit of a Gundam unit. The first ever case of MS vs. MS combat took place on September 18, UC 0079, when Amuro destroyed two Zaku IIs with the Gundam. This point marks the beginning of the story of Mobile Suit Gundam. It also set into motion a series of events that would sent the White Base to Earth crewed almost entirely by civilian refugees. On October 4, Earth Attack Force commander Garma Zabi was killed while leading an attack against the White Base in North America.

Operation Odessa
Operation Odessa was the Earth Federation's first major offensive campaign on Earth. A chance to strike back opened up with the death of Garma Zabi. Operation Odessa used 30% of the Federation Army to take out the Zeon mining facilities in the Odessa region, the lynchpin of the Principality supply network. Launched in early November, the objective of the campaign was to capture the Zeon mining facilities at Odessa and drive Zeon forces out of Europe and Asia. The operation was launched on November 7, ending two days later in victory for the Earth Federation. This was remarkable for the fact that the Earth Federation Forces consisted almost entirely of conventional forces, tanks and aircraft, and yet managed to defeat the Zeon force consisting of many mobile suits. The Earth Federation did have a small number of mobile suits at the battle, but they were mainly used in mopping up operations, and contributed relatively little to the battle. Operation Odessa marks the turning point of the One Year War, the beginning of the end for Zeon's forces in Europe and Asia. However, the leader of the Zeon mining operations Colonel M'Quve had enough mining material sent to the Zeon homeland allowing Zeon to continue the war without the danger of supply shortages.

In the TV series version of Mobile Suit Gundam the White Base played a more important role. M'Quve had the aid of a traitor within the Federation General Elron where through the associate Judoc planned to sabotage the operation by holding back the troops led by Elron to allow M'Quve's forces to attack the troops belonging to General Revil. White Base pilots Amuro Ray and Sayla Mass accidentally witness Judoc's Federation-commissioned plane leave a Zeon base without incident and they follow it and it leads to Elron and Judoc's arrest allowing Elron and Revil's forces to easily overpower M'Quve's forces unsuspecting forces. In desperation, M'Quve tried to break the Antarctic Treaty by launching a nuclear missile but Amuro and the Gundam are able to disable it. From there, the determined Federation emancipated Europe, Asia and eventually North America. The remaining Zeon troops regrouped for a massive assault on Jaburo base, hoping to kill the heart of the Federation.

Battle of Jaburo
On November 29, White Base finally reached the HQ of Earth Federation forces, Jaburo. In the same time, Char Aznable found the main entrance of Jaburo. Zeon began their initial attack by launching air raids. Char led a commando squad to infiltrate Jaburo through another way after wiping out a post with a squad of MSM-04 Acguys. Char's squad found out the GM manufacturing factory inside Jaburo and planted bombs on the GMs, to be found by the orphans from White Base. On the following morning, California Base sent several Dopps and Gaws to attack Jaburo, bringing a lot of MSs to be air-dropped and several marine-type MSs attacked Jaburo through river. However, Zeon miscalculated Jaburo's defenses, the Federation officers agreed that White Base's presence would lure Zeon to Jaburo. That was why Federation had a better defense against Zeon and introduced some of their newly mass-produced GMs to the Zeon and outpowered the Zeon's MSs, but not without losing some of the GMs, tanks and other non-MSs weaponries. The defense on the space port was the thickest one, since White Base was ported there and led the defending soldiers to defend it, since they expected White Base to bring the war to end. On the other part of Jaburo, there was a new Gundam, RX-78-6 Mudrock Gundam defending it, however, it was destroyed by the Zeon's Midnight Fenrir. Char, defeated in a duel against Gundam, retreated from Jaburo and the other Zeon forces retreated later on, with only the Zeon troops in North Africa continuing their resistance. After the battle, White Base left for space to provide a decoy operation.

Battle of Baldur Bay
On December 5th, Dozle's Conscon Fleet reached Baldur Bay of the neutral Side 6, as White Base was docked in that neutral colony side. In the same time, White Base decided to leave Side 6 and engaged the Conscon Fleet. It was during this battle that MS-09R Rick Doms were used in huge number for the second time in a skirmish (Lieutenant Dren also deployed a lot of Rick Doms when White Base was on the Earth's orbit, earlier than Conscon did, marking the replacement of Zaku IIs by Rick Doms), replacing the Zakus which were the former standard MSs for Zeon's Space Attack Force. White Base attacked a Musai-class cruiser and destroyed it a very few moments after it exited Side 6's perimeter. Conscon berated White Base of playing dirty and ordered a full-out attack on White Base, to be losing 12 units of Rick Doms within 3 minutes by the Federation's infamous Gundam. Those Rick Doms were no match for Amuro, as his Newtype's abilities were growing stronger, causing him to have fast response to destroy those Rick Doms. Conscon's Chivvay-class was destroyed by Amuro who charged towards it after destroying those Rick Doms

Operation Cemballo
On December 14, the Earth Federation launched an offensive into space from their fortress Jaburo. This was the start of Operation Cemballo. Sending their new fleets into space, the EFSF moved towards the Zeon homeland at L2. Standing in their way was the Zeon defensive line, consisting of the asteroid space fortresses Solomon and A Baoa Qu, as well as the lunar city Granada. On Christmas Eve, December 24, UC 0079, the EFSF fleet launched an attack on the asteroid base Solomon, the headquarters of Zeon's Space Attack Force. Using their Solar Flare System, the Earth Federation was able to take Solomon. When it was clear that the battle was lost, Zeon Space Attack Force Dozle Zabi gave the order to evacuate the base and sortied in the Big Zam to fight a delaying action. He succeeded in allowing many Zeon forces to retreat, but was killed by Amuro Ray in the process. The capture of Solomon marks the end of Operation Cemballo.

A possible, yet very critical, mistake on Zeon's part laid within the misconception of the Gundam's status. Rumors of the Gundam's head by itself in battle lead to the idea that the Gundam was taken out very early, leading to Anavel Gato to pull away and allow Amuro Ray to slip in. Had this not have happened, the battle might have ended differently.

Operation Star One
Using the newly captured Solomon as a staging area, the Earth Federation Space Forces continued their offensive toward Side 3 in Operation Star One. On December 30, with the Earth Federation Forces en route to the Zeon asteroid base A Baoa Qu, Zeon leader Sovereign Degwin Zabi approached the EFSF fleet with the intention of negotiating an end to the war. Despite knowing that his father was in the line of fire, Gihren Zabi gave the order to fire the Solar Ray system at the EFSF fleet which was assembling at Geldova Line, destroying a full third of the Earth Federation fleet present and killing both Degwin Zabi and General Revil in the process.
 * See Also A Baoa Qu

Despite these losses, the Earth Federation continued their attack on A Baoa Qu. They assaulted the asteroid base on New Year's Eve, December 31, UC 0079. With their remaining forces, the EFSF fought against the gathered forces of Zeon's Mobile Attack Force and A Baoa Qu's garrison forces. During the battle Kycilia Zabi executed her half-brother Gihren Zabi for the crime of murdering their father Degwin Zabi, and took command of the battle herself. In the confusion this caused, some Zeon forces -- notably the Delaz Fleet -- fled before the battle was over. When it became clear that the Zeon forces would lose, Kycillia herself attempted to retreat; however, she was killed by Char Aznable before she could escape.

War's End
After Zeon's defeat at A Baoa Qu, and the death of the leadership on both sides of the conflict, the newly restored Republic of Zeon surrendered to the Earth Federation. The two parties signed a peace treaty at Granada on New Year's Day, January 1, UC 0080. By the terms of the treaty, Side 3 was allowed to keep its independence. However, some of Zeon's remaining military was dissatisfied with the conclusion of the war, and chose to retreat to the Zeon base Axis in the asteroid belt. Still more people, such as the Delaz Fleet, decided to remain in the Earth Sphere, hiding from the Earth Federation with the hope of one day striking back at them. Others groups, stranded on Earth and unwilling to surrender, hid themselves and only emerged years later, during Operation Stardust or the first Neo Zeon invasion of Earth.

Aftermath
The One Year War set the stage for many of the Universal Century's later conflicts. The Delaz Fleet's Operation Stardust was a direct result of renegade Zeon soldier's dissatisfaction with the outcome of the war. The Titans were created to counter this threat, thus setting the stage for the Gryps Conflict. The Axis Zeon faction, which later became the First Neo Zeon, was also formed as a direct result of the One Year War, and their actions heavily influenced the Gryps Conflict and the First Neo Zeon War. Other groups, such as the Second Neo Zeon and "The Sleeves", are not spawned directly from the One Year War, but can trace their roots indirectly back to the conflict.

Trivia

 * This war is actually based on the real world's World War II, however, what differs them are that One Year War is set in the future and a fictional war, where as humanoid robots (Mobile suits) and mobile armors replacing WWII's vehicles, i.e. MS as tanks or fighter aircrafts and MA as tank destroyers or attacker/bomber aircrafts. However in One Year War, foot soldiers, tanks, submarines, and aircrafts also play a huge role in the war like what they played in the real life WWII.
 * Gundam SEED's Bloody Valentine War resembles One Year War, however, there are great differences between them too. In One Year War, Zeon declared war against Federation to achieve independence (though in truth Zeon had already achieved this under Zeon Zum Daikun's administration), while Earth Alliance (CE counterpart of Earth Federation) declared war against PLANT/ZAFT (CE counterpart of Zeon) because of racial friction and the prior destruction of the UN (which was blamed on the PLANTs). One Year War had a bloody beginning like Bloody Valentine War, but in different way: One Year War begun with Zeon attacking Federation's Side 1, 2 and 4, causing the death of about 2.8 billion fellow colony inhabitants; while Bloody Valentine War begun with a nuclear missile fired by an Earth Alliance's mobile armor to Junius Seven, a colony of PLANT, causing the death of about 0.29 million colony inhabitants. However, the similarilities are that both Zeon and ZAFT have mobile suits that overpowered Earth Federation and Earth Alliance in the earlier stages of war and later, both Earth Federation and Earth Alliance produced their own mobile suits and surpassed Zeon and ZAFT. Though the later stages of the two wars are radically different, the BVW ended by the intervention of the Three Ship Alliance, and ZAFT still officially controlled a relatively significant portion of Earth, while in OYW, Zeon was almost completely driven away from Earth, and only a few remenants remain as fugitives.
 * The war between the colonists and earthlings before the main story of Gundam Wing is also loosely based on this war too. (the story of Gundam Wing itself is loosely based on the story of Zeta Gundam, or the Gryps War).