“Sengokuhara Onsen Senkyoro” is a long-established, venerable hot spring inn in Sengokuhara, Hakone-machi, Ashigarashimo-gun, Kanagawa Prefecture, founded in 1870. Its milky-white hot spring, which naturally gushes forth and is drawn from Owakudani using only natural differences in elevation, can be enjoyed in every bath without any added water or circulation, in a completely free-flowing system (100% natural source flowing directly from the spring). The spring quality is acidic, calcium, magnesium, sulfate, and chloride. Thanks to its acidity and abundant main components, its high usefulness for beautiful skin and the skin barrier has been scientifically demonstrated. Guests can fully savor the exquisite onsen atmosphere in the elevated, clear air of Sengokuhara, with luxurious open-air baths and guest rooms with 100% natural source flowing baths.