In the post-Soviet Caucasus, a number of borders remain blocked as a result of ethno-territorial conflicts that emerged in the early 1990s. Yet, there is one closed border that does not fit the pattern: the Turkish–Armenian border. This border has not been the site of any conflict in that period, and belongs to an entirely different geopolitical space: the border that previously separated the Soviet Union from Turkey, as well as independent Armenia from the Republic of Turkey. To understand the nature of the conflict that keeps the Turkish–Armenian border closed, therefore, one has to look for historic references that go beyond the Soviet legacy and bring in Ottoman history, and specifically the Genocide of Ottoman Armenians in 1915–1916. This analysis sheds new light on understanding the modern conflicts of the Caucasus, which have previously been studied mostly within the context of the Soviet experience.