A Limestone Cave Explored by Wading
The Irimizu Cave (入水鍾乳洞, Irimizu Shonyudo) is a limestone cave in the karst plateau of Mount Otakine, straddling Takine and Tokiwa in Tamura City, Fukushima Prefecture, which in 1934 was designated a Natural Monument.
The Agency for Cultural Affairs lists it under the criterion for caves, and records no managing body.
According to the Tamura City board of education text displayed by the cave office, local people exploring the area found it in 1927, and it was first called the Takine Fudo Cave. It took the name Irimizu Cave when it was designated.
How the Cave Formed
Cultural Heritage Online explains that on the karst plateau of crystalline limestone, water swallowed by a sinkhole runs beneath the plateau and emerges on the mountainside at 560 metres above sea level, where the entrance of the Irimizu Cave opens.
The designation text describes the water of the Waseda River, east of the plateau, sinking through a sinkhole and dissolving the limestone to form the cave. Inside, it says, the water runs fast, with waterfalls and deep potholes that make exploration unusually difficult.
With so much water, erosion continues even as new calcium carbonate is deposited, so stalactites and stalagmites are well developed. The cave extends for a little over 900 metres.
What to Look For: Courses A, B and C
The cave office divides the cave into three courses: A goes 150 metres in, B 600 metres and C 900 metres. There is only one entrance, so visitors turn back at the end of their course and walk twice the distance.
Course A is an ordinary show cave needing no preparation. Course B follows the stream through the cave and needs a headlamp, a change of clothes and footwear that can get wet. Tamura City notes that the water is about 10 degrees and in places reaches the knee.
The board of education text describes countless oddly shaped stalactites, the largest about 1 metre across, and named features such as the Fudo Falls, Jizo Cave, Doll Tiers and Lion Rock.
Visiting the Irimizu Cave
The cave office gives reception hours of 8:30 a.m. to 4:30 p.m. for course A and 8:30 a.m. to 3:30 p.m. for course B. Course C requires a guide and booking, and is currently offered only as a reward for Tamura City's hometown tax donations. Payment is by cash only, and there is no cash machine nearby.
Tamura City's page (updated in 2023) gives prices of 600 yen for adults and 500 yen for children on course A, and 1,000 yen and 800 yen on course B. Check current prices with the cave office.
It is about 30 minutes on foot or 5 minutes by taxi from Sugaya Station on the JR Ban'etsu East Line, and about 20 minutes by car from the Ono or Tamura Smart interchange on the Ban'etsu Expressway. The cave office is at 89-3 Dairoku, Sugaya, Takine-machi, Tamura; telephone 0247-78-3393.
Q&A
- When was the Irimizu Cave designated?
- It was designated a Natural Monument on 28 December 1934.
- When was the Irimizu Cave discovered?
- In 1927, by local people; it was first called the Takine Fudo Cave.
- What are the courses at the Irimizu Cave?
- Course A goes 150 metres in everyday clothes, course B 600 metres wading through water, and course C 900 metres with a guide.
- What do I need for course B at the Irimizu Cave?
- A headlamp, a change of clothes and footwear that can get wet; the water is about 10 degrees.
- How do I get to the Irimizu Cave?
- About 30 minutes on foot from JR Sugaya Station, or about 20 minutes by car from the Ono interchange of the Ban'etsu Expressway.
Basic Information
| Name | Irimizu Cave (入水鍾乳洞) |
|---|---|
| Location | Takine and Tokiwa, Tamura City, Fukushima Prefecture |
| Designation | Natural Monument |
| Year Designated | Designated 1934/12/28 (Showa 9) |
| Quantity | Not recorded in the Agency for Cultural Affairs database |
| Dimensions | A little over 900 metres in total length |
| Owner | Not recorded in the Agency for Cultural Affairs database |
| Public Access | Open (courses A and B without booking, course C by reservation) |
References
- Agency for Cultural Affairs Database: Irimizu Cave (Japanese)
- https://kunishitei.bunka.go.jp/bsys/maindetails/401/355
- Cultural Heritage Online: Irimizu Cave (Japanese)
- https://online.bunka.go.jp/heritages/detail/171505
- Tamura City: Irimizu Cave (Japanese)
- https://www.city.tamura.lg.jp/soshiki/19/abukuma-syounyuudou-irimizu-syounyuudou_1.html
- Irimizu Cave: Map and History (Japanese)
- https://www.irimizu.com/maphistory
- Irimizu Cave: Access (Japanese)
- https://www.irimizu.com/access
- Irimizu Cave: Prices (Japanese)
- https://www.irimizu.com/price
Last verified: 2026.09.27