Guida
Chatsubomi Moss Park is located in the mountains of Nakajo Town, Gunma Prefecture, and serves as the largest breeding ground in Japan for the Chatsubomi moss. This location provides the perfect environment for this specific species, which thrives under highly acidic conditions. In 2017, the area was designated as a National Natural Monument, specifically recognized as the 'Rogo Chatsubomi Moss Biological Community and Iron Ore Formation Site.' The park is a fascinating site where the remnants of a former mine blend seamlessly with extraordinary natural formations.
The site is the former location of the 'Gunma Iron Mountain.' Development began around 1943 to secure metal resources, with large-scale mining operations taking place to address resource shortages during the war era. Historically, iron ore was transported using railways and ropeways (aerial tramways). Although mining ceased in 1965 due to the depletion of resources, the site has been preserved and developed into a park that highlights its unique topography. From a geological perspective, the landscape is a striking result of volcanic activity, which created the acidic environment and iron-rich components that define this area.
Within the park, you can observe the Chatsubomi moss, a plant uniquely adapted to highly acidic environments. This moss grows through a process involving the formation of limonite (iron ore) driven by biological activity in an iron-rich environment. The sight of the vivid green moss integrated with the surrounding rocks and terrain is a spectacle found nowhere else. Additionally, the physical remains of the former mining site serve as a powerful testament to the area's industrial history.
The best time to visit is between June and August, when the Chatsubomi moss is most active. During these summer months, you can witness the most vibrant colors of the plants and feel the intense vitality of nature. The park is open from 8:45 AM to 3:00 PM, and we highly recommend visiting during the bright daylight hours to fully appreciate the colors.
The primary activity is nature observation. You can walk through the area to observe the rare Chatsubomi moss and its unique habitat up close. The quiet environment allows for a peaceful experience of both the natural formations and the historical mining topography. No specialized botanical knowledge is required to enjoy the visual splendor of this unique ecosystem.
The area around Nakajo Town is dotted with hot spring resorts (onsen) and other natural scenic spots. The region is characterized by the flow of the Agatsuma River and landscapes shaped by volcanic activity, making it an excellent destination for travelers interested in exploring unique geological and geographical features.
As this is a protected natural park, visitors must show respect for the plants and the environment. Because the terrain can be uneven, we strongly recommend wearing comfortable walking shoes or hiking shoes. Please ensure you complete your visit within the park's operating hours. We ask all visitors to follow local rules to help preserve this precious natural environment.