Kitashiobara Village, Yama County, Fukushima Prefecture. About a 20-minute walk from the Urabandai Site Station along the "Renge・Nakase Pond Exploration Trail." The scenery visible from the observation deck within the trail is Nakase Pond.
While Goshikinuma is famous for its "various blue lakes and marshes," Nakase-numa is tranquil. It is a suitable path for a leisurely stroll, engaging in dialogue with oneself while basking in the light filtering through the trees. The sounds of wild birds and the occasional sound of water can be heard.
A small hill appears to float in the middle of the marsh──.
From the observation deck on the exploration path, looking down at the marsh, hills are scattered across the green surface of the water, resembling islands. Trees grow, moss thrives, and they look as if they have been there for hundreds of years. However, this landscape was not like this until just over 100 years ago.
Why are the hills in the marsh there?
These hills are referred to in geology as "nagareyama".
On the morning of July 15, 1888 (Meiji 21), Kobandai, located on the north side of Mount Bandai, suddenly collapsed. It was a landslide. The fallen rocks and debris flowed downwards at speeds exceeding 100 km/h towards the base. This is called "gansetsu nadare".
The flowing debris dammed rivers, filled valleys, engulfed Hibara Village, and created approximately 300 lakes and marshes.
And──among the large boulders carried by the debris flow, some of a certain size were not completely shattered in the current and were transported as chunks, remaining as "hills" where they stopped.
That is the nagareyama.
The hills that appear to float in Nakase-numa are all boulders that were transported in one go on the morning of July 15, 1888. The parts that rise above the water surface appear as hills, but beneath the water, larger bodies are resting.
Geosite certified by the Bandai Geopark
The area of the Urabandai Goshikinuma marshes, including Nakase-numa, is a certified geosite of the Bandai Geopark. It is known as one of the few places in Japan where "the landforms created by volcanoes can be observed in real time."
Typically, landslides and debris flows are geological events that occur on a scale of tens of thousands to hundreds of thousands of years. Their "traces" can only be deciphered through boring surveys conducted by specialists.
However, the nagareyama of Nakase-numa has traces of an event that occurred just 137 years ago, right before our eyes. Without reading specialized books, one can understand with the naked eye, "Ah, that hill is the rock that flowed here." Such a friendly geological heritage is rare even globally.
Walking after knowing, Nakase-numa
Walking along the Nakase-numa exploration trail without knowing anything is a peaceful nature stroll. The fresh green mirror, the chirping of birds, and the occasional sound of water.
However, when you walk knowing that 'the hill in the middle of that swamp is a rock that flew in on July 15, 1888,' the scenery becomes completely different.
When we guide visitors at Nakase-numa, the moment we arrive at the observation deck, we tell them, 'That is Nagareyama.' It's a usual moment when they ask, 'What do you mean?' After that, for 20 minutes, while talking about the rock debris avalanche and Mount Bandai, when we look down at the swamp again, the expressions on our guests' faces completely change.
The surface of the swamp water becomes more than just a surface. The hill becomes more than just a hill. This is a place where the time of the Earth and the time of humans intersect at your feet──that moment of realization is here.
If you visit Nakase-numa
Nakase-numa is located in Kitashiobara Village, Yamagata Prefecture. It takes about 20 minutes from the Urabandai Site Station parking lot via the exploration trail. The trail is relatively flat, but there is a slope for a section leading to the observation deck. It's a course that is easy to walk even for those who are not very confident in their physical strength.
The season of fresh greenery (May to June) is the most beautiful
The biggest highlight of Nakase-numa is the view of Mount Bandai and Nagareyama from the observation deck. Right in front is the explosive crater of Mount Bandai. Below it spreads the scenery of Nakase-numa. You can encounter beautiful landscapes throughout the four seasons.
Places you want to visit together
- Goshikinuma Nature Exploration Trail ── A 'trail where you can see various shades of blue created by the same rock debris avalanche.' Combine it with Nakase-numa for a leisurely visit.
- Lake Hibara ── The largest lake in Urabandai, formed by a rock debris avalanche blocking a river. The village of Hibara sleeps beneath the lake.
- Bandai Mountain Geopark ── You can learn about the landforms created by volcanic eruptions from a geological perspective.
Would you like to join us on a journey to encounter stories?
At Tabinoito, guide Catherine, who has lived in Urabandai and Aizu for half a century, shares stories of the land that are not found in guidebooks, providing guidance limited to one group per day.
The 'Half-day course of geology and history' that visits the three points of Nakase-numa's Nagareyama, Goshikinuma's blue swamp, and the sunken village of Lake Hibara in one go can also be arranged upon consultation. You can leave all long-distance driving and arrangements to us.
If you want to "walk slowly in nature" or "take a stroll as a couple"—whatever your request, feel free to reach out. A consultation is fine, and we will not engage in any persistent solicitation.
👉 Free consultation via LINE:
https://page.line.me/tabinoito
👉 View travel plans for senior couples:
https://tabinoito.com/senior/
👉 View travel plans for filial piety:
https://tabinoito.com/oyakouko/
Related articles:
The village submerged at the bottom of the lake ── Memories of Hibara Village erased by the 1888 eruption of Mount Bandai
Reference materials
- Bandai Mountain Geopark - Goshiki-numa Lake Area
- 1888 Mount Bandai Eruption (Wikipedia)
- Bandai Asahi National Park (Ministry of the Environment)
- Urabandai Visitor Center Local Exhibits and Interviews
- On-site coverage (Visit and interviews by Tabinoito guide, Catherine)
About the author of this article
Catherine ── A guide who has lived in Fukushima Prefecture, Urabandai, and Aizu for half a century. Founder of the private tour company "Tabinoito." Deeply knowledgeable about local nature, history, and cultural beliefs. Offering guided tours of Urabandai and Aizu while sharing stories of the land that are not found in guidebooks, limited to one group per day.
