Nagayu Onsen (hot spring) in Oita Prefecture is listed as one of the hundred best hot springs in Japan along with Beppu Onsen and Yufuin Onsen in the same prefecture. It is said that it was discovered in the 8th century and has a long history since then. The characteristic of Nagayu Onsen, the onsen loved by people for a long time, is its carbonated spring which is regarded to have the best favorable effect among other carbonated springs in Japan. The carbonated spring in Nagayu Onsen is also good for health as drinking water. There are not only public baths but also places where you can drink the water as well.