Nagaoka-kyō

Nagaoka-kyo was the capital of Japan for a single decade, from 784 to 794, spanning roughly 4.3 by 5.3 kilometers across what are now the cities of Muko and Nagaokakyo, the town of Oyamazaki, and the Nishikyo ward of Kyoto in Kyoto Prefecture. Emperor Kanmu established it 40 kilometers north of the earlier capital Heijo-kyo to overcome the geographical weaknesses of that earlier site, drawing on access to three rivers and a new port system. After the assassination of a key advisor and a series of disasters blamed on a vengeful spirit, the imperial court abandoned the site for Heian-kyo in 794, and the palace ruins went undiscovered until 1954, when they were later designated a National Historic Site.