Nagorno-Karabakh Line of Contact

The Line of Contact (, "shp’man gits", ) separated the Armenian forces (namely the Nagorno-Karabakh Defense Army) and the Azerbaijan Armed Forces since the First Nagorno-Karabakh war. It was formed in the aftermath of the May 1994 ceasefire that ended the First Nagorno-Karabakh War (1988–94). The mountain range of Murovdag is the northern part of the line of contact and is essentially a natural border between the two forces. The length of the line of contact was between and until 2020. It was slightly changed for the first time since the 1994 ceasefire during the Nagorno-Karabakh conflict of 2016, and aspects of the current line of contact since the 2020 ceasefire following Second Nagorno-Karabakh War remain unclear.
Terminology.
The term "Line of Contact" is widely used in official documents and statements, including by the OSCE Minsk Group.
Some Armenian analysts, including Ara Papian encourage the Armenian side to avoid the term "line of contact", instead calling it a "state border" between Artsakh and Azerbaijan. Independent journalist and author Tatul Hakobyan writes of it as a state border of Azerbaijan and Artsakh and notes that it is called the "line of contact" in international lexicon.
In Azerbaijan, the “line of contact” is often referred to as the “line of occupation” in accordance with designating Nagorno-Karabakh an occupied territory.
Description.
The line of contact was, immediately after the ceasefire, a "relatively quiet zone with barbed wire and lightly armed soldiers sitting in trenches", according to Thomas de Waal. There was also a relatively large no-man's land after the ceasefire which was several kilometers wide in some places. It was reduced to a few hundred meters in most areas of the line of contact due to Azerbaijani redeployments into the former neutral zone. In 2016, there were around 20,000 men on each side of the heavily militarized line of contact. Since the ceasefire the line of contact has become a heavily militarized, fortified and mined no-man's-land and a buffer zone of trenches. According to de Waal, it is the "most militarised zone in the wider Europe," and one of the three most militarized zones in the world (along with Kashmir and Korea). The trenches along the line of contact have been extensively compared to those of World War I.
The line of contact is regularly monitored by a group of six OSCE observers, headed by Andrzej Kasprzyk of Poland. There are exchanges of fire virtually on a daily basis. There have been significant violations of the ceasefire on various occasions, usually characterized by low-intensity fighting. Significant fighting occurred in April 2016, when for the first time since the ceasefire the line of contact was shifted, though not significantly. According to Laurence Broers of Chatham House, "Although slivers of territory changed hands for the first time since 1994, little of strategic significance appears to have altered on the ground." The 2016 clashes also marked the first time since the 1994 ceasefire that heavy artillery was used, while the 2020 Nagorno-Karabakh conflict saw use of heavy artillery, armoured warfare, and drone warfare. On October 9, 2020, when President of Azerbaijan Ilham Aliyev addressed the nation, he stated, "There is no status quo. There is no line of contact. We smashed it."
Impact.
According to Kolosov and Zotova (2020), "the deployment of military units along the separation line, the special regime of the border zone on both sides, constant skirmishes, and the destruction during the war and immediately after it of a number of cities and other settlements turned the border territories into an economic desert." 
According to the International Crisis Group, all of 150,000 Karabakh Armenians are "within reach of Azerbaijani missiles and artillery shells", while around twice the number of Azerbaijanis (300,000) "live in the 15km-wide zone along the Azerbaijani side of the line of contact."