One Year War
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Date: January 3rd, UC 0079 - January 1st,  UC 0080
  • Principality of Zeon
  • Earth Federation
Status: Federal Victory...
  • Principality of Zeon under authority of the Treaty of Grenada
  • Zabi Family KIA...
  • Humanity Recovers from It's half extinction...
  • Heirshy takes over the Party until UC 0084...
  • Brought about the beginning of Mobile Suit Warfare...

Yoshiyuki Tomino

The One Year War is the largest military conflict depicted in the Universal Century series, involving tens of thousand of mobile weapons, thousands of war ships and millions of combatants. Its casualties, both military personnel and civilians were in the billions. 

The war is also known as the Zeon's War of Independence to the former soldiers of the Principality of Zeon.

The  One Year War begins on January 3, UC 0079 (the Universal Century calendar begins some time after 2045 AD, according to the official timeline). A short period in the first week of the war is known as the "One Week Battle" or the "One Week War", in which most civilian casualties are accrued by the indiscriminate use of WMDs and surprise attacks.

The portion of the war depicted in the original anime, Mobile Suit Gundam depicts mainly the last few months of the "One Year War", where only the introductory narration mentioned the earlier events including destruction of multiple space colonies and the dropping of an Island 3 type colony from orbit, resulting in the destruction of half of the human population.

The war ended on January 1, UC 0080, when the Republic of Zeon, reinstated after the defeat and isolation of the Principality, signed a peace treaty with the Earth Federation.

Overview Edit

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.

Zeons Rise To Power Edit

When the leader of the Republic of Zeon became gravely ill he mentioned only one name on his death bed, "Degwin Zabi". The people of Republic of Zeon took this to mean that Zeon Zum Deikun was naming Degwin to succeed him as leader of the Republic in UC 0068. After being appointed as the leader of the Republic of Zeon, Degwin Zabi adopted the title of Sodo, meaning "Lord", and was referred to from them on as Degwin Sodo Zabi. Seizing control of the government, Degwin maintained the only way for the colonies to be independent of the Earth Federation was for the Principality to fight (though in reality Side 3 was already independent of Earth at that time). To this end Degwin appointed his own children into military and political offices, and pushed for rapid development of military technology. Gihren Zabi, the eldest of the Zabi children remained at his fathers side as his aide, achieving the rank of Admiral and eventually became the Supreme Commander of the Zeon Armed Forces in place of his father. Dozle Zabi, the second eldest son of the Zabi family, became Vice Admiral and the Commander of the Zeon Space Attack Force, responsible for overseeing fleet movements within the Principality and securing areas. Kycilia Zabi, a Vice Admiral as well, shared command of the Zeon Space Attack Force with her brother Dolze, which led to conflicts between the two as she operated from the lunar city of Granada. Garma Zabi, the youngest of the Zabi family was placed in command of the Zeon Earth Attack Force.

With the backing of the Principality of Zeon's new leadership, technological breakthroughs were made in a number of fields of research. One of the largest developments was that of mobile suit technology, which while originally intended for colony construction found military applications. Research by Doctor Minovsky lead to the discovery of the Minovsky Particle and the Minovsky Particle Effect, which allowed for the development of further technology, such as the Minovsky Craft System. Supported by Kycilia Zabi, research into a growing phenomenon led to the classification and discovery of Newtypes, and with her support the development of Newtype based military units.

Negotiations with the Earth Federation finally broke down in UC 0079, leading to the Principality of Zeon (re)declaring its independence from the Earth Federation and at the same time declaring war on the Federation.

One Year War Edit

Early Weeks Edit

One of the first groups of colonies to be drawn into the conflict were the colonies located at Side 1, also called Zarn, which served as the capital of the Earth Federation in space. The group of colonies at Side 2 (also known as Hatte) and Side 4 (also known as Mua) were drawn into the conflict as well, with one of the devastated colonies from either Side 2 or Side 4 being used for "Operation British", which was to use a colony as a weapon by sending it on a collision course with the Earth. Operation British met with moderate success, as an explosion caused the colony to alter its trajectory and instead of impacting on the Earth based capital of the Earth Federation, it instead landed on Sydney, Australia, destroying 16% of the continent. While attempting to gain another colony to drop onto the Earth, the Earth Federation Space Forces intercepted the Zeon Space Attack Force at Side 5 (also known as Loum), resulting in the "Battle of Loum". The resulting battle employed the use of both nuclear and biological weapons, causing the complete destruction of Side 5 as both forces attempted to bring a quick end to the war.

The massive loss of life at the Battle of Loum resulted in a truce being called between the Earth Federation and the Principality of Zeon in order for representatives of both governments, as well as those of other colonies, to meet and discuss the terms of the war. This meeting lead to the signing of the Antarctic Treaty, which prohibited the use of nuclear and biological weapons by both the Earth Federation and the Principality of Zeon. The treaty also outlined that colonies could not be used as weapons in the conflict, the treatment of prisoners of war, and the neutrality of other colonies that wished to remain out of the war, becoming a safe haven for refugees.

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. Operation British was a complete failure.

The Loum SkirmishEdit

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 its 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, Heirshy, 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.

Antarctic TreatyEdit

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.

Fall of Side 1Edit

Earth Invasion Edit

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, with New Harrison fighting amongst the ground Invasion. 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.

Project VEdit

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, Heirshy, then entered Side 7, along with other Zaku II's 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, while being supported by both Char Aznable, and Heirshy, whom were also on a search and destroy mission for the Trojan Horse.

Battle of OdessaEdit

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.

This battle was the largest and the bloodiest battle on Earth, where Earth Federation relied heavily on conventional weapons such as tanks, bombers, air fighters and a few amounts of MSs (30 units) and in large numbers of troops (amounted 3,700,000 troops) lost more lives compared to much smaller but much powerful Principality of Zeon (having only small amounts of air fighters, tanks, bombers, cannon and artillery but huge amounts of MSs which are move advantageous against Earth Federation's forces) but Earth Federation won the battle. (The complete statistics of the battle can be seen on Odessa)

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, New Harrison while fighting in the Desert was also betrayed, by Rambal Ral, and was presummed Destroyed by Gundam on the second day of Operation Odessa.

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.

Several days before the attack, Heirshy returned, from Solomon, now under the control of Dozie Zabi, and stated that he would also take part in the attack.

Attack on JaburoEdit

Main article: Invasion of Jaburo (One Year War)

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, While Heirshy discovered weak points in the Federation's Defensive lines. 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.

Baldar Bay RaidEdit

After the Battle of Jaburo ended and White Base launched back into space, a Zanzibar commanded by Char Aznable caught up with it, only to let the nearby Zeon patrol, the Camel Patrol Team led by Char's ex-lieutenant Dren engage White Base. New Harrison supported the attack on White base, but By this time, Zeon had replaced their Space Attack Force's mainstay MSs Zaku II with newer MS-09R Rick Dom. Instead of cutting off White Base's route of providing decoy, the whole patrol team was wiped out by White Base's forces. After the battle, White Base went to Side 6 for repairs. Zeon Space Attack Force's commander Vice Admiral Dozle Zabi, worrying of Earth Federation Space Forces built-up at Luna II, dispatched the Conscon Fleet to trap the White Base while he remained stationed at Solomon to observe Federation's movements.

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. White Base left Side 6 and engaged the Conscon Fleet. 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 for playing dirty and ordered a full-out attack on White Base, but lost 12 Rick Doms within 3 minutes, most of them to the Federation's infamous Gundam. Those Rick Doms were no match for Amuro, New Harrison eventually whom was fighting in a farther distance eventually, took part in the fight, but eventually was forced to withdraw. Though victorious Amuro recived damaged from fighting Harrison, and had to withdraw as well.

Days later Amuro as his Newtype abilities were growing stronger, making his reaction time much faster. Conscon's Chivvay-class was destroyed by Amuro who charged towards it after destroying the Rick Doms.

Federation Mass for Counter AttackEdit

On December, Zeon intelligence learned of Earth Federation's secret project in the Arctic: The development of the RX-78NT-1 Gundam "Alex", the intended successor for Amuro's RX-78-2 Gundam. Zeon sent the Cyclops Team, a special task force, to capture the project materials before they were sent to space. However, things went badly for the Cyclops Team as the Federation launched the materials into space before Cyclops Team could stop them. On December 14, Gray Phantom arrived at Side 6's Libot colony Federation base. The Cyclops Team infiltrated Libot to learn the location of the Gundam in preparation for an attempt to capture it. On December 19, Cyclops Team launched an attack with their MS-18E Kämpfer, as a diversion, while other members of the team infiltrated the Federation's base, disguised as Federation soldiers. Most of the Cyclops Team members, including the leader Hardy, were killed in action. Christina MacKenzie sortied in the Gundam "Alex" to stop Zeon's MS-18E Kämpfer, piloted by Mikhail Kaminsky to try to prevent it from causing more damage on Libot. With the mission apparently ending in failure, Colonel Killing ordered the destruction of Libot colony with a nuclear missile.

The last remaining member of the Cyclops team, Bernard Wiseman, in an effort to save the colony by completing the mission, launched an attack against the Federation base on Christmas with his MS-06FZ Zaku II Kai. Christina then launched in Gundam "Alex" in an attempt to stop him without further damage to the colony. At the end of the battle, both machines were severely damaged, and Wiseman was killed. Operation Rubicon ended in failure, as the Cyclops Team had failed to capture or destroy Federation's new Gundam. The Gundam, however, was in no condition to be sent into battle, and the war ended only a week later. The operation itself saw the violation of 2 points in the Antarctic Treaty, as Zeon had attacked a neutral colony and later attempted to destroy it with nuclear weapons.

Final Weeks Edit

Invasion of SolomonEdit

Battle for the Atmosphere

Principality of Zeon battle for strategic control of the Earth Atmosphere...

On December 14, Operation Cemballo began with the launch of a new Earth Federation fleet from their fortress Jaburo. 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 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 System, the Earth Federation inflicted heavy damage on the enemy fortress and 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.

Operation Star OneEdit

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. Gihren Zabi gave the order to fire the Solar Ray at the EFSF fleet which was assembling at Geldova Line, knowing that his father was in the line of fire. This attack destroyed a full third of the Earth Federation fleet present and killed both Degwin Zabi and General Revil in the process.

Despite these losses, the Earth Federation continued their attack on A Baoa Qu. They assaulted the asteroid base on 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 EndEdit

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. Some of these forces retreated to the Zeon base Axis in the asteroid belt, while others, such as the Delaz Fleet and various remnant forces on Earth, remained in the Earth Sphere, hiding from the Earth Federation with the hope of one day striking back at them.

The Principality of Zeon after the One Year War, was Isolated on one side of Side 3, and under the Treaty of Grenada was forbidden from ever achieving or acquiring any source of Military presence or raising an Army, as doing so would lead to the Party's dismantlement, despite these strict new laws that were handed over against Heirshy and Zeon, the Principality was still allowed to use its forces for training simulations while under the constant supervision of the Republic of Zeon.

However this Treaty of Isolation would eventually be lifted about 28 years later in UC.108 during a Bloody conflict that they were engaged in since UC.0096. The Treaty of Grenada was terminated completely at the conclusion of the Battle of Earth by UC.108, finally allowing the Principality of Zeon to act Independently once again against their war with Terrorist Empire Neo Zeon.

Aftermath Edit

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 soldiers' 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.


  • The One Year War, was the first known War in the History of Mankind to produce Mobile Suits fighting against one another, and was also known as the first known war to develop Mobile Armors...
  • This event was the first known War in History to concern the Principality of Zeon as enemies against the Earth Federation...
  • The One Year War would be the main cause for most of Earth's hatred against the Principality of Zeon, even during, and after the Zeon Civil War...
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