Founded in 1715 during the Shotoku era, Kinokuniya is one of Hakone's most venerable ryokan, with a lineage spanning over three centuries in the secluded mountain village of Ashino-yu. The hot spring district dates back to the era of Hakone's legendary Seven Hot Springs, where Ashino-yu was praised as the finest among them, described in historical texts as possessing the "five flavors" of water. The inn earned the distinction of serving as a resting place for Emperor Meiji during his travels, and luminaries such as Katsu Kaishu and Shiga Naoya sought inspiration within its walls. Nearby stands the restored Tokouan Yakushido temple, where the haiku poet Buson once composed verses celebrating the spirit of Ashino-yu — a testament to the cultural heritage that permeates this tranquil corner of Hakone.

The defining feature of Kinokuniya is its possession of two chemically distinct hot spring sources. The first is a naturally flowing simple sulfur spring that produces beautifully milky-white water with a neutral pH of 7.0, gentle on the skin and rich in metasilicic acid at 139 mg — earning its reputation as a "beauty spring." The second source, drawn from the Yunohana-sawa valley, is a calcium-sodium-magnesium sulfate-bicarbonate spring, crystal clear yet containing an impressive 192 mg of metasilicic acid. Both sources flow directly from the earth without recirculation, and across the sprawling 3,000-tsubo grounds, 15 individual springs feed 15 baths of varying character and size.

The main building houses the Yukoden bathhouse, where bathers immerse themselves in cloudy sulfur-rich waters, while the annex's Kihinden offers the contrasting experience of soaking in clear bicarbonate spring water. Each bathhouse features both indoor and open-air baths, set against the serene backdrop of Hakone's forested mountains. Overnight guests gain access to the exclusive Shotoku no Yu private bath, a lovingly recreated Edo-period bathing chamber where both spring types can be enjoyed side by side. Accommodation starts at 19,600 yen per person with two meals, featuring cuisine crafted from Hakone's seasonal ingredients.

Day-use bathing is available at a reasonable 1,000 yen for a two-hour visit — an accessible price point for a Hakone hot spring of this caliber. Despite being just a 25-minute bus ride from Hakone-Yumoto Station followed by a 2-minute walk from Higashi Ashino-yu bus stop, the inn occupies a world apart from Hakone's bustling tourist corridors. Winter brings the pleasure of snow-viewing baths framed by frosted peaks, while spring and early summer envelop the open-air baths in fresh greenery. With Lake Ashi, Hakone Shrine, and Owakudani all within easy reach, Kinokuniya serves as an ideal base for exploring the wider Hakone region.