Nanki-Katsuura Onsen (南紀勝浦温泉) is a coastal onsen, or hot spring, located in Nachikatsuura, Wakayama Prefecture, Japan. Originally known as "Katsuura Onsen", the "Nanki-" was added to distinguish it from another onsen in Katsuura, Chiba. Known as the "Matsushima of Kii", Nanki-Katsuura Onsen is one of the most popular hot springs in Japan due to its location along the coast and springs within caves.[1] The spring is listed as the "Top 100 Onsens" by Kankokeizai News.[2] | ||||||