Yugawara Onsen Gensen Uenoya湯河原温泉 源泉 上野屋

Uenoya sits at 宮上616 on the Miyakami River, about ten minutes by taxi from Yugawara Station. The main building is a wooden complex constructed between Taishō 12 (1923) and Shōwa 12 (1937) - not restored to look old but genuinely old, with exposed timber framing, lattice screens, and the particular density of a building that has been maintained rather than renovated. The property was added to the national 登録有形文化財 registry in 2010, one of a small number of ryokan buildings in Kanagawa to carry the designation. Natsume Sōseki and Yokoyama Taikan are both attributed as past guests - the attribution circulates in secondary sources rather than on any official plaque, but it is plausible given Yugawara's literary history from the Meiji period onward. The ryokan has operated at this address for over 300 years; the building visible today is its Taishō-Shōwa reconstruction.

Uenoya operates two wells at approximately 300 metres depth beneath the property - one currently active, one in reserve. The spring is classified as ナトリウム・カルシウム－塩化物・硫酸塩泉, the same mineral type as the municipal 混合泉 that most other Yugawara facilities use, but this is a wholly self-sourced supply distinct from the town's shared distribution network. The water emerges at up to 82°C and enters 六瓢の湯 without dilution or chlorination - 源泉かけ流し on the public indoor bath. pH is measured in the range of 7.89-8.3 across field sources; TDS is 1,714 mg/kg. Visitor reviews consistently single out the water quality as Yugawara's highest, and a Tripadvisor pool of 40 reviews places Uenoya at #16 of 68 Yugawara properties - strong for a facility whose core offering is a narrow afternoon window in a single shared bath.

Day-use guests access 六瓢の湯, the indoor bath on the first floor. The bath is granite and cypress with a warm tub and a hot tub running simultaneously; 六瓢の湯 rotates by gender morning and evening, so the configuration you enter depends on when you arrive. Four additional baths exist: a rooftop foot bath, 仄幸の湯, and two outdoor private charter baths on the fourth floor - 藤木 and 千歳 - but the private baths are for lodging guests only. Whether the rooftop foot bath is accessible to day visitors was not confirmed in research; ask at the front desk on arrival. The facility also sells spring water for home delivery at ¥2,500-3,000 per 10-20 litres, an arrangement that appears to be unique to Uenoya on the Yugawara day-use circuit.

The day-use window is narrow by design: 14:00-17:00, Sunday and weekday afternoons only, no Saturday. This is a working ryokan with lodging guests whose check-in lands in the same window; the afternoon slot is the gap between the morning cleaning cycle and the evening lodger preparation. At ¥1,000 for three hours in a 300-year wooden building with unchlorinated spring water, the value is real - but only if you plan around the hours. Niftyonsen lists 14:00-17:00, but the operator website does not publish day-use hours directly. Call 0465-62-2155 before driving up, particularly outside peak tourist season, to confirm the window is still open. Parking in the Miyakami valley is limited; the closest public lot is a short walk from the entrance. In the Yugawara onsen lineup, Uenoya holds the water-quality slot - no other day-use facility in the valley offers kakenagashi in an untouched pre-war building at this price point.

住所: 神奈川県足柄下郡湯河原町宮上616

電話番号: 0465-62-2155

営業時間: 14:00-17:00 (Sunday and weekdays only; Saturday excluded)

タオル: Not published. Bring your own towel recommended for day-use guests; confirm rental availability by phone.

浴槽の種類: 内湯（六瓢の湯 - 花崗岩・ひのき）, 貸切露天（藤木 - 4F、宿泊者専用）, 貸切露天（千歳 - 4F、宿泊者専用）, 足湯（仄幸の湯 - 屋上）

源泉: 自家源泉（宮上）

泉質: ナトリウム・カルシウム－塩化物・硫酸塩泉

源泉温度: 82°C

pH: 8.1

温泉の取り扱い: 源泉かけ流し

「湯河原1番の泉質」

The best spring water quality in Yugawara.

「国の有形文化財に指定されているそうで、なるほどと納得」

I heard it's a nationally registered cultural property - and once you see it, you understand why.

「日帰りでここまで丁寧な対応をしてくれるとは…次回泊まりたくなってしまう宿」

I didn't expect this level of care for a day visitor - it made me want to come back and stay overnight.

「源泉かけ流しで塩素の匂いが全くない」

Flow-through spring water with no chlorine smell at all.

「全館木造の風情ある宿で、入浴だけでも来る価値があります」

A wooden inn with real character - worth the trip just for the bath.

「湯上がりの肌がすべすべになりました」

My skin felt silky smooth after the bath.

「日帰り入浴は14時から17時まで。事前に確認することをお勧めします」

Day-use runs 14:00-17:00. I'd recommend calling ahead to confirm.

複数のプラットフォームで収集した情報に矛盾があった箇所です。

• Day-use hours source conflict - operator silent: Niftyonsen lists 日帰り入浴 14:00-17:00, Sunday and weekdays only, ¥1,000. The official operator website (uenoya-net.jp) does not publish day-use hours. This is the weakest data point on the guide page - call 0465-62-2155 before visiting to confirm the window is open and the Saturday exclusion still applies. Hours are published as Nifty-sourced pending direct operator confirmation.
• Per-bath water handling split (§7.17): 六瓢の湯 (day-use indoor bath): 源泉かけ流し, no chlorination, no dilution - confirmed by Niftyonsen and 秘湯宿.com. Private charter baths (藤木 / 千歳): operator notes 加水 on filling (presumably required to cool from 82°C to bathing temperature). These baths are lodger-only; day-use guests access 六瓢 only. waterHandling is set to 源泉かけ流し because that is what day visitors actually encounter.
• Source temperature spread across sources: Operator and Nifty quote 82°C; field sources (秘湯宿.com) note the spread 71-82°C across sources; pH range 7.89-8.3 across field measurements vs 8.4 operator quote. TDS 1,714 mg/kg from Nifty. Spring temperature set to 82°C on the guide page (the operator's stated figure); pH averaged to 8.1 in the spring object. Confidence medium on exact values.
• Historic guest attribution: Natsume Sōseki and Yokoyama Taikan are attributed as past guests in secondary sources (blogs, tourism copy). Neither attribution has been confirmed from the operator directly or from a period document. The claim is plausible given Yugawara's literary history but remains medium-confidence. The guide page flags this: 'attributed in secondary sources rather than on any official plaque.'
• Rooftop foot bath (仄幸の湯) day-use access unconfirmed: 仄幸の湯 is listed on the operator's bath inventory but its availability for day-use guests vs. lodging guests only was not confirmed in research. The guide page notes this and directs visitors to ask at the front desk. Do not promote it as a day-use feature until confirmed.

• 上野屋 公式サイト
• 上野屋 お風呂案内
• Niftyonsen - 湯河原温泉 源泉 上野屋
• Surugabank 井伊部長の温泉グルメ探訪
• 秘湯宿.com 日帰り温泉レポート