This onsen is very natural. After entering the main building, in order to get to the baths you have to go through another set of doors which lead you back outside and down a small wood-covered path to the baths (which are situated in a rustic wooden building). There is no shower area but instead a small indoor bath made of stones and an area with buckets to rinse yourself before getting in. (There is also a sauna) The outdoor bath is fantastic as it is situated nearly in the river. There is also a small walk next to the onsen where you can see some natural steam vents and bubbling mud pits. It almost feels prehistoric. Also, be warned, the area has a very high concentration of sulfur so don't be surprised by the smell!