The One Year War
This account of the One Year War serves as a prologue of sorts to the original Gundam series. Though the early days of the war have never been portrayed on-screen, they have great repercussions throughout Gundam history.
The One Week War
The cataclysmic conflict later known as the One Year War begins on January 3, UC 0079. Three seconds after declaring a war of independence against the Earth Federation, the upstart Principality of Zeon launches massive attacks on the space colonies at Sides 1, 2 and 4. Zeon forces bombard the Federation fleets stationed at these Sides with nuclear weapons and pump poison gas into the colonies, routing the unprepared Federal Forces and killing 2.8 billion people with their destructive tactics.
Attempting to bring the war to a swift conclusion, Zeon then launches Operation British. Zeon forces attach engines to one of the now-depopulated colonies and force it out of orbit, intending to drop the 20-mile-long cylinder onto the Federation's headquarters at Jaburo in South America. The Earth Federal Forces intercept the falling colony, but are repulsed by the Zeon mobile suits guarding it.
Though the falling colony does impact on Earth, it breaks up into several pieces during its entry into the atmosphere and consequently misses its target. Colony fragments rain down upon North America, while the largest chunk lands on Sydney, Australia, where it creates an impact equivalent to a 60,000 megaton blast. The Sydney impact creates destroys one-sixth of the Australian continent, creating a 500-kilometer crater and killing 200 million people. The casualty toll for the first days of the conflict, referred to as the One Week War, now stands at about three billion people.
The Ruum Campaign
On January 15, the Principality of Zeon makes a second attempt to carry out Operation British. Entering Side 5, Zeon forces begin attaching engines to another colony in order to take a second shot at Jaburo. This time the Earth Federal Forces are ready for them, dispatching an armada three times the size of Zeon's to prevent the colony drop. The Zeon forces quickly abandon their mission and instead launch an all-out attack on the Federation fleet. The two sides begin lobbing nuclear missiles back and forth, laying waste to Side 5 and killing 2.5 billion people. From the colloquial name for Side 5, this conflict is known as the Ruum Campaign.
Zeon's mobile suits prove to be devastatingly effective in this unprecedented space battle. A lone Zeon pilot, Char Aznable, destroys five Federation battleships. Although the Federal Forces prevent the activation of the engines, the Federation armada is wiped out and its commander, General Revil, is captured by Zeon's elite Black Trinary pilot team. Both sides withdraw, having turned Side 5 into a "shoal zone" of debris and colony fragments.
The Antarctic Treaty
Less than two weeks into the war, the indiscriminate use of nuclear weapons and chemical warfare have killed half the human race. Earth's climate has also been ravaged by the effects of Operation British, and a small-scale "nuclear winter" is under way. Shocked by the carnage, the Earth Federation and the Principality of Zeon meet for negotiations in Antarctica.