A sodium-led simple sulfur spring rising at 52.7 °C — hot, alkaline (pH 8.9), and faintly carrying the rotten-egg note of H₂S at the source. The slippery alkaline feel puts it in Japan's classic 'beauty-water' family, while 5.0 mg/kg of bisulfide and a bicarbonate-carbonate backbone give it a soft, rounded body — a gentle sulfur spring rather than a sharp one.
pH
8.90
Alkaline
Source temperature
52.7°C
Hot
Tonicity
0.24g/kg
Hypotonic
Flow rate
6,340L/min
Very high
Free CO₂
0.20mg/kg
Low
色
Color
colorless and transparent
香
Odor
with a faint sulfur note
Highlights
Sulfur-rich
Top-decile alkaline
Analyzed Mar 14, 2014·有限会社奈良環境調和研究所·Cert no. 温-1403
612. Taki no Yu Spa, Tosenji Onsen, Totsukawa, Nara ★★★
Onsen for 800. Operating hours stated as 08:30 to 20:00 (closed Thursdays). They stamp the 88 Onsen of Wakayama booklet.
The outdoor bath is located separately, down a staircase. Very cool view of the forest and partially the river. Railings limit the view from inside the bath itself, but don't prevent you from enjoying the overall atmosphere. Clear water with occasional small mineral deposits, a subtle proper sulfurous onsen smell. Water temperature was 44.5 both days.
Had a cool nature story here. Sat in the rotenburo while it was pouring rain. A large insect flew in, like a butterfly/beetle (looked harmless). It was flying right in front of me across the entire bath area, then started dipping into the water, scooping it up every couple of seconds. At first I thought it was going to fall in, but it kept doing these deliberate scoops about 20 times (I started counting at some point). Then the insect turned around and flew confidently off toward the forest.
Indoor bath with clear water, subtle proper sulfurous onsen smell. Water temperature was 46 on the first day, and 48 the next morning right at opening. Breathable inside, though barely.
Super cool outdoor bath, a must-visit in this area.
14.06.2025 15.06.2025