Ninomaru Onsen

紀州忍びの湯二ノ丸温泉きしゅうしのびのゆにノまるおんせん

Other

Kansai·Wakayama

0737-64-1826 ninomaru-onsen.jp

Day Use

Yes

Bathing & Water

Outdoor BathYes

Open-air outdoor bath

OnsenYes

Uses natural hot spring water

湯浅町温泉

Yuasa-cho Onsen

Sampled at wellhead

湯

Simple

Classification

Sodium Bicarbonate-Carbonate-Sulfate spring

A simple thermal spring in Yuasa-cho, Wakayama. With pH 9.5 it sits at the strongly-alkaline edge of the scale; sodium dominates the cation side (94 percent of equivalents), giving the slippery, soft-water feel associated with Japans beauty-water family. Source temperature is 30.4 C — a cold-side low-temp spring that is reheated for bathing. Mineralization is light (194 mg/kg dissolved solids), so the water is mild rather than assertive.

pH

9.50

Alkaline

Source temperature

30.4°C

Low temp.

Tonicity

0.19g/kg

Hypotonic

Flow rate

36L/min

Low

Color: colorless and transparent
Taste: tasteless
Odor: odorless

Highlights

Strongly alkaline

Analyzed Mar 22, 2019·和歌山県環境衛生研究センター·Cert no. 温泉第1087号

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1 year ago

502. Ninomaru Onsen, Wakayama ★ Onsen for 1300. Inconvenient to get to. Operating hours 10:00 to 21:30 (Mon-Wed, Fri) and 08:00 to 21:30 (Sat-Sun), closed Thursdays. Overnight stay option available. They stamp the 88 Wakayama Onsens passport. Bath photos from the internet, matches roughly — visited in the evening. Outdoor zone requires going down some stairs: 1. Outdoor bath. View of trees. Maple branches hang in front of the bath — should be gorgeous during autumn foliage season. If you stand up, you can see the river. Clear water, temperature 44. 2. Sauna. 3. Cold bath. 4. Indoor bath with clear water, temperature 42. There's a barrel with cold water. Breathing inside is fine. Interesting place, would especially love to see it during momiji season. 11.04.2025