Yataijin Numa (Gunma Prefecture) Complete Guide: A Valuable Artesian Spring and Natural Artesian Phenomenon Observation Spot in Ota City
Yataijin Numa (矢太神沼), located in the northwestern part of Ota City in Gunma Prefecture, is a precious tourist destination known for its abundant spring water and unique natural environment. This marsh, formed by clear water gushing forth from the Yataijin Water Source, is cherished by nature enthusiasts and environmental education visitors as an observation point for artesian phenomena and a habitat for rare organisms.
What is Yataijin Numa: Ota City’s Representative Artesian Spring Spot
Yataijin Numa is a natural marsh located in the northwestern part of Ota City, Gunma Prefecture, at the toe of the Omama alluvial fan. In this area centered around an elevation of approximately 60 meters, numerous springs are observed, and the Yataijin Water Source (矢太神水源) is known as the spring point with the most abundant water volume.
Currently, the area surrounding Yataijin Numa has been developed as “Hotaru no Sato Park,” serving as a place of rest where local residents and tourists can experience nature. There is a water source point on the northwest side of the park, and to its south spreads Yataijin Numa, measuring approximately 15 meters east to west and 80 meters north to south.
Historical Background of Yataijin Numa
The northwestern part of Ota City, where Yataijin Numa is located, has long been known as a region blessed with water resources. This area occupies an important position as part of the Nitta Manor archaeological site, and the Yataijin Water Source is a precious water source that has historically supported the region’s life.
Due to the geological characteristics of the Omama alluvial fan, a natural mechanism by which groundwater flowing from mountainous areas gushes forth at the toe of the fan has created this rich spring environment. The clear water that continues to flow unchanged through the ages is a precious natural heritage that conveys the region’s history and culture to the present day.
Characteristics of Yataijin Water Source: One of Gunma Prefecture’s Most Abundant Springs
Yataijin Water Source is one of the most noteworthy spring sites in Gunma Prefecture. It has been selected by the Ministry of the Environment as a “Representative Spring,” and its water quality and abundant water volume are highly evaluated.
Abundant Water Volume and Water Quality
The greatest characteristic of Yataijin Water Source is its abundant water volume. While multiple spring points exist in the northwestern part of Ota City, Yataijin Water Source has the highest water volume among them and maintains a stable discharge volume throughout the year.
The gushing water has high transparency, and the water temperature remains nearly constant throughout the year. This stable water environment enables the habitation of rare organisms, as described later.
Observation Point for Artesian Phenomena
One of the greatest attractions of visiting Yataijin Water Source is observing the artesian phenomenon. At the spring point, you can witness up close the spectacle of water gushing vigorously from underground and sending sand swirling upward.
This artesian phenomenon is a phenomenon in which groundwater pressure naturally pushes water to the surface, and it is also evidence of the existence of abundant groundwater veins. The sight of sand swirling is dynamically beautiful, as if the water were alive, captivating all who visit.
The time of day best suited for observation is from late morning to around noon, when sunlight falls on the water surface. Depending on the light conditions, the flow of gushing water and the swirling sand become more clearly observable.
Precious Ecosystem: Habitat of Nihon Kawamozuku
Yataijin Numa and its surrounding waters have a biologically very important environment. Of particular note is the habitation of “Nihon Kawamozuku” (日本川藻屑), a rare red alga.
What is Nihon Kawamozuku
Nihon Kawamozuku is a precious red alga species that inhabits only clean streams. It is extremely sensitive to water pollution and can only grow in clean water environments, so its very existence serves as an indicator of good water quality.
The waters surrounding Yataijin Numa maintain a precious environment where Nihon Kawamozuku can inhabit, making it an important location from an environmental conservation perspective. The conditions of stable water temperature, clean water quality, and appropriate water flow together enable the habitation of this rare species.
Other Biota
As the name “Hotaru no Sato Park” suggests, the area surrounding Yataijin Numa is also known as a habitat for fireflies. During early summer, Genji fireflies and Heike fireflies emit mystical light, allowing visitors to feel the mystery of nature.
The clear water environment also hosts numerous freshwater fish such as killifish and loaches, crustaceans such as freshwater crabs, and aquatic insects such as dragonflies. Water-side plants are also abundant, allowing for enjoyable nature observation throughout the four seasons.
Hotaru no Sato Park: Development Status Around Yataijin Numa
“Hotaru no Sato Park,” developed around Yataijin Numa, is a park designed with consideration for preserving the natural environment while enabling visitors to comfortably experience nature.
Park Facilities and Equipment
Walking trails are installed throughout the park, allowing visitors to enjoy a stroll while visiting Yataijin Numa and the spring point. Wooden decks and observation areas are also provided, creating an environment well-suited for observing artesian phenomena and aquatic organisms.
The park is fully equipped with parking, making access by car convenient. However, due to natural environment protection, care must be taken regarding eating, drinking, and bringing in garbage within the park. When visiting, please follow the rules and manners for protecting nature.
Seasonal Charm
The area surrounding Yataijin Numa reveals different charms with each season.
In spring, fresh greenery is beautiful, and waterside plants bud. The sight of fresh green reflected on the clear water surface is exceptional.
Summer is firefly season. From June through July, you can enjoy the mystical light of fireflies from dusk into the evening. This season particularly attracts many tourists.
In autumn, surrounding trees change color, creating beautiful scenery through the contrast of fall foliage and clear streams.
Winter sees fewer visitors and is quiet, but it is the ideal season for observing spring water phenomena in clear air. Since the water temperature is constant, springs continue to flow even in winter without freezing.
Access to Yataijin Numa
We introduce methods for accessing Yataijin Numa (Hotaru no Sato Park).
Access by Car
Car access is most convenient.
- From Ota Kiryu IC on the Kita-Kanto Expressway: Approximately 15 minutes
- From Honjo Kodama IC on the Kan-etsu Expressway: Approximately 40 minutes
When using a car navigation system, search for “Hotaru no Sato Park” or “Yataijin Water Source.” The park is equipped with a free parking lot.
Access by Public Transportation
To access by public transportation:
- From Ota Station on the Tobu Isesaki Line: Approximately 20 minutes by taxi
- From Yabuzuka Station on the Tobu Kiryu Line: Approximately 15 minutes by taxi
Access by public transportation alone is somewhat inconvenient, so a rental car or taxi is recommended.
Address and Basic Information
- Location: Nitta Ichinoi-cho, Ota City, Gunma Prefecture
- Hours: Open 24 hours (please exercise caution regarding safety for nighttime visits)
- Admission: Free
- Parking: Free
- Inquiries: Ota City Board of Education Cultural Properties Section
Nearby Tourist Spots and Combination Plans
When visiting Yataijin Numa, it is also recommended to combine it with other tourist attractions in the surrounding Ota City area.
Nitta Manor Archaeological Site Group
The Yataijin Water Source is positioned as part of the Nitta Manor archaeological site. Nitta Manor is a medieval manor ruins designated as a national historic site, and is especially recommended for those interested in history.
By combining a historical tour visiting nearby historic sites such as Shina Shrine, Sorimachi Mansion Ruins, and Toshogu, you can enjoy more enriched sightseeing.
Japan Snake Center
Located approximately 20 minutes by car, the Japan Snake Center is a rare facility displaying snakes from around the world. You can learn about organisms from a different angle than through nature observation.
Ota City Museum of Art and Library
Located near Ota Station, the Ota City Museum of Art and Library is a cultural facility also noteworthy for its architectural design. Enjoying art and reading after nature walks is also recommended.
Michi no Eki Ota
Michi no Eki Ota, where you can purchase fresh local agricultural products and specialties, is also recommended as a stop-off point. You can fully experience the charm of Ota City.
Precautions and Etiquette When Visiting Yataijin Numa
Yataijin Numa is a place where precious natural environments are preserved. Please note the following when visiting.
Consideration for Environmental Protection
- Always take trash with you: Taking trash with you is essential for protecting the natural environment
- Do not collect organisms: Please do not injure or collect precious organisms such as Nihon Kawamozuku
- Do not pollute water quality: Please do not allow detergents or chemical substances to enter the water
- Do not damage plants: Avoid stepping off walking trails and be careful not to trample plants
Safety Precautions
- Pay attention to footing: Since waterside areas are slippery, wear appropriate footwear when visiting
- Do not take your eyes off children: If visiting with young children, please exercise full caution to prevent water-related accidents
- Nighttime visits: When visiting at night for firefly viewing, bring a flashlight and pay full attention to your footing
Observation Etiquette
- Observe quietly: Avoid making loud noises so as not to disturb the natural environment
- Refrain from flash photography: Consider the impact on organisms, and especially avoid flash photography during firefly season
- Be considerate of other visitors: Exercise a spirit of consideration when sharing observation spots
Environmental Conservation Activities at Yataijin Numa
The beautiful natural environment of Yataijin Numa is preserved through environmental conservation efforts by local residents and Ota City.
Water Quality Conservation Efforts
Ota City regularly conducts water quality surveys at spring sites including Yataijin Water Source. By continuously collecting water quality data, environmental changes are detected early, and appropriate conservation measures are implemented.
Additionally, development and land use in surrounding areas are carefully handled considering impacts on the spring environment.
Conservation Activities by Local Residents
Regular cleaning activities and environmental conservation efforts by local residents are also conducted. The cooperation of volunteer members in the community greatly contributes to the maintenance and management of Hotaru no Sato Park.
Fine-tuned conservation activities including firefly habitat protection, invasive species control, and waterside vegetation management are continuously carried out.
As a Place for Environmental Education
Yataijin Numa is also utilized as a site for environmental education at local elementary and middle schools. The opportunity for children to actually observe springs and aquatic organisms provides a precious opportunity to learn the importance of environmental conservation.
Such environmental education for future generations is an important effort for protecting the nature of Yataijin Numa in years to come.
Photography Spots and Best Seasons at Yataijin Numa
Yataijin Numa is also well-suited for photography. For those wishing to capture the beauty of nature in photographs, we introduce recommended photography points and best seasons.
Recommended Photography Points
Artesian phenomenon at the water source: To capture the sight of sand swirling upward, shooting from directly above the water source point is recommended. Morning light is particularly beautiful for photography.
Full view of Yataijin Numa: From the south side of the marsh looking northward, you can capture the entire marsh and surrounding greenery.
Waterside plants and reflection on water surface: Photography utilizing the reflection of sky and trees on the water surface is also appealing. A calm, windless day is best.
Seasonal Photography Tips
Spring (March–May): The contrast between the beauty of fresh greenery and clear water is appealing. Budding waterside plants also become subjects for photography.
Summer (June–August): Long exposure photography of firefly light trails is possible. You can capture mystical photographs using extended exposure, and a tripod is essential.
Autumn (September–November): The combination of fall foliage and water surface is beautiful. Leaves floating on the water surface also have charm.
Winter (December–February): You may be able to photograph steam rising from the water source in clear air. Early morning is especially recommended.
Ota City’s Spring Water Culture and the Position of Yataijin Numa
To understand Yataijin Numa, it is also important to know the spring water culture of Ota City as a whole.
Geological Features of the Omama Alluvial Fan
The northwestern part of Ota City is located at the toe of the Omama alluvial fan. An alluvial fan is a fan-shaped landform formed by rivers that have emerged from mountainous areas depositing sediment into plains.
In the upper part of alluvial fans, river water easily infiltrates underground, and at the toe of the fan, groundwater easily gushes forth due to geological characteristics. Due to this natural mechanism, numerous spring points exist in the northwestern part of Ota City.
Springs Supporting Life
Historically, these springs played important roles as domestic water and agricultural water supporting the region’s life. Yataijin Water Source is no exception, with a history of being valued as a precious water source supporting the livelihood of local residents.
In modern times, tap water has been installed, reducing dependence on springs, but their environmental and cultural value remains highly appreciated.
Comparison with Springs in Gunma Prefecture
Many other spring sites exist throughout Gunma Prefecture. Spring groups at the foot of Mount Haruna, springs at the foot of Mount Akagi, and springs in the Agatsuma region all possess distinctive spring characteristics.
Among these, Yataijin Water Source is particularly noteworthy as one of the most remarkable springs in terms of abundant water volume, the ease of observing artesian phenomena, and the habitation of rare organisms.
Ways to Enjoy Visiting Yataijin Numa: Purpose-Based Guide
We propose ways to enjoy Yataijin Numa according to visitors’ purposes.
For Those Wanting to Enjoy Nature Observation
Starting with observation of the artesian phenomenon at the water source point and progressing to observation of aquatic organisms is recommended. Bringing binoculars or a magnifying glass allows for more detailed observation.
You can observe diverse biota including waterside plants, insects, and birds. Since different organisms can be seen depending on the season, there are new discoveries with each visit.
Keeping observation records in a notebook will lead to deeper understanding of nature.
For Those Wanting to Enjoy Photography
Based on the aforementioned photography points, visit by choosing appropriate times of day and seasons. Particularly if aiming for firefly photography, the period from mid-June to early July around the new moon is optimal.
Bringing a macro lens allows you to also enjoy close-up photography of aquatic organisms and waterside plants.
As Family Leisure
When visiting with young children, observing water creatures while exercising caution for safety is recommended. Organisms such as killifish and freshwater crabs, which easily capture children’s interest, are observable.
However, refrain from collecting organisms and maintain a “look only” observation approach. It also becomes a good opportunity for environmental education.
For Those Seeking Healing and Silence
Visiting during times when fewer visitors are present, such as weekday mornings, allows you to listen to natural sounds in a quiet environment.
The sound of gushing water, bird songs, and the sound of trees swaying in the wind allow you to be enveloped in nature’s music and refresh both body and mind.
Spending time slowly sitting on a bench is also recommended.
Conclusion: The Charm and Visiting Value of Yataijin Numa
Yataijin Numa is a precious natural spot that Gunma Prefecture’s Ota City is proud to offer. It possesses diverse charms including abundant spring water from the Yataijin Water Source, easily observable artesian phenomena, the habitation of rare Nihon Kawamozuku, and the mystical sight of fireflies dancing at night.
It is a natural blessing created by the geological characteristics of the Omama alluvial fan and a precious environment that conveys the region’s history and culture to the present day. The fact that it has been developed as Hotaru no Sato Park and can be easily visited by anyone is also a major attraction.
Each visitor can enjoy Yataijin Numa according to their own purpose, whether it be nature observation, photography, environmental education, or restorative time. When visiting Gunma Prefecture, Yataijin Numa is definitely a tourist spot worth a visit.
Why not experience the mystery and beauty of nature at Yataijin Numa, where clear water continues to spring forth? When visiting, remember to consider environmental conservation, and enjoy while upholding good manners as one who will help pass this precious nature on to the future.
