Shanxi is a Systems Alliance colony located near the Shanxi-Theta mass relay. Besides being the jumping off point for local traffic, Shanxi is notable for its involvement in the First Contact War of 2157. It was the site of several battles between the Systems Alliance and the Turian Hierarchy.
Prior to 2186, Shanxi was the only human colony to have ever been occupied by an alien race.
The Occupation of Shanxi
After an expedition sent through the Shanxi-Theta mass relay was wiped out by a turian patrol fleet, a single ship survived and made it back to Shanxi itself. A retaliatory force was sent out by the commander at the colony, and the reinforcements destroyed the turian forces. Events escalated quickly; the turians sent more ships through the relay and captured Shanxi, but not before a message drone was sent out by the defenders, alerting the Alliance forces at Arcturus Station.
The Alliance defenders at Shanxi, besieged by the orbiting turians, were then forced to fight a guerrilla campaign on the ground. The turians, however, slowly squeezed the defenders into submission. Dropping orbiting debris, the turians leveled entire city blocks just to destroy one marine fire team whenever they attempted to procure food and supplies. Eventually, with the troops starving and civilians dying every day, the garrison surrendered and the turians occupied the colony.
However, the turians then faced logistical problems of their own as their unique biology required them to import all of their food. Nevertheless, the turian forces believed they were secure, and that the handful of ships they had defeated represented the bulk of human naval forces. They were unprepared when the Second Fleet under Admiral Kastanie Drescher launched a powerful counteroffensive and evicted them from Shanxi.
In response, the turians began mobilizing for full-scale war. However, after seeing the turians forced off of Shanxi, the Citadel Council realised just how well-trained, equipped and adaptable the Alliance forces were, and understood that a war between the turians and the Alliance could be devastating to the galaxy. They intervened and brokered a truce.
Mass Effect: Evolution
In the midst of the turian siege of Shanxi, a turian research vessel carrying a valuable artifact crash-landed on the planet. The Turian Hierarchy dispatched General Desolas to locate the missing vessel, the artifact, and the researchers. During the search, Desolas was captured by the human mercenaries Jack Harper, Ben Hislop, and Eva Coré, who then tracked down Desolas's squad, captured them, and stumbled upon the cave where the turian researchers had hidden the artifact. The tables were turned on the mercs when the artifact incapacitated Jack and Ben, distracting Eva long enough for the turians to free themselves. Desolas took the humans prisoner and notified the Hierarchy that the artifact had been located. Their mission complete, the turians departed the planet with the artifact and their prisoners, who were later freed at a post-war prisoner exchange on Arcturus Station.
Shanxi is sometimes used as an example by xenophobic political groups like Terra Firma to protest against humanity's growing interactions with alien races. In response to arguments that the turian actions at the Shanxi-Theta relay were all a big misunderstanding, equivalent to snatching a gun away from a child, Terra Firma leader Charles Saracino responds that he would take the gun away from the child, "but I wouldn't shoot them dead."
The First Contact War and the Battle of Shanxi created great mistrust between humans and turians. However, Shanxi also proved humanity's tenacity and military strength. It impressed the turians and the galactic community as a whole, because apart from the krogan, the turians had previously found no equals in war. The battle created a lot of interest in humans on the Citadel.
When talking to Commander Shepard about having a drink to celebrate Armistice Day, Ashley Williams confesses that her grandfather, General Williams, was the commander at Shanxi when the colony surrendered to the turians. No charges were ever brought, but the incident destroyed his career. He eventually left the military, and ended up working construction out in the colonies. There have been some attempts by Alliance historians to exonerate General Williams "in some official way," but nothing has yet come of these efforts.
Shanxi was also chosen to host a Terra Firma political rally in 2173, likely intended to underline the colony's significance to the pro-human contingent. Party leadership candidate Claude Menneau was expected to attend, but mysteriously disappeared en route.
Mass Effect 2
Shanxi has a regular shuttle route to Nos Astra on Illium. Due to security advisories, after several human colonies had been attacked, the route is delayed (canceled) until further notice.