Inunakiyama Onsen Yamanoyu

Located in Ogi, Izumisano City, Osaka Prefecture, along the upper gorge of the Kashii River, Yamanoyu is the source bath (yumoto) of Inunakiyama Onsen, the only hot spring village in Osaka Prefecture. The spring was discovered around 1959, when the father of the current owner, Takahara Nagafumi, founded a drilling company and struck hot spring water at a depth of 310 meters in under a year. Since the opening of Kansai International Airport it has been promoted as "the hot spring closest to the world," and in recent years it has also drawn visitors as a power spot alongside the ascetic training grounds and waterfalls of nearby Shippo-taki Temple on Mt. Inunaki.

The water is classified as a simple sulfur spring with a mildly alkaline pH of around 8.8. Because the source temperature is only around 18°C, a cold mineral spring, the water is mechanically pumped up and heated before use and is circulated rather than continuously flowing fresh, though no dilution water is added. The bath water is pale and cloudy with fine white and brown mineral flecks and carries a faint sulfurous scent. Its silky, slippery texture has earned it a reputation as a "beauty bath."

The facility itself is simple, with a single indoor bath and large windows overlooking the surrounding greenery. There is a rest area and vending machines, and kamameshi (rice hot pot) can be ordered. Admission is 700 yen for adults and 300 yen for children, and the bath is open daily from 10:00 to 18:00 with no regular closing days. The spring water drawn here also supplies the neighboring inns, making Yamanoyu the functional source of the entire Inunakiyama hot spring village.