Minamiaiki Village is a quiet mountain community in Minamisaku District, Nagano Prefecture. Stretching from east to west, the village is surrounded by mountains and wilderness, with roughly 80 percent of its total area covered by forests and open mountainous land. Ten settlements are scattered along the Minamiaiki River, preserving the peaceful scenery and traditional atmosphere of a Japanese mountain village.
While surrounded by pristine nature, the people of Minamiaiki have carefully maintained their traditional way of life and local landscape. For visitors, the village offers a chance to slow down and experience the tranquility of rural Japan.
One of the most distinctive attractions in Minamiaiki Village is Minamiaiki Dam. Built by TEPCO Renewable Power for a pumped-storage hydroelectric power project, the dam stands at an elevation of approximately 1,532 meters, making it one of the highest dams in Japan.
The dam is a 136-meter-high rockfill dam built on the upper reaches of the Minamiaiki River, part of the Shinano River system. It serves as the upper reservoir for the Kannagawa Power Station. Water is circulated between Minamiaiki Dam and Ueno Dam in Ueno Village, Gunma Prefecture, which serves as the lower reservoir, supporting a large-scale power generation project with a maximum planned output of 2.82 million kilowatts.
The artificial lake created by Minamiaiki Dam is known as Oku-Mikawa Lake. Set high in the mountains, the lake offers magnificent scenery, and on clear days visitors can enjoy views toward the majestic Yatsugatake mountain range.
The appearance of the lake changes beautifully with the seasons. Surrounded by mountains and forests, it is an especially peaceful place to appreciate the relationship between modern infrastructure and the natural landscape.
Parks have been developed both upstream and downstream of Minamiaiki Dam, and the area has become one of the village’s distinctive tourism resources.
Particularly notable is Uzumaku Hiroba, a plaza on the downstream side. Its artistic design expresses three concepts—“spiral,” “flow,” and “helix”—through limestone, water, and concrete walls. The unusual design has been recognized for its aesthetic and creative value, earning a Good Design Award in fiscal 2006.
The plaza can also be reached by car, making it an accessible destination for families and visitors exploring the mountain landscape.
The construction of Minamiaiki Dam also brought significant economic benefits to the village. Increased property tax revenue contributed to more stable local finances, and from fiscal 2006 onward Minamiaiki became a municipality that did not receive ordinary local allocation tax grants.
The village’s experience demonstrates how a small mountain community can make use of its natural environment and infrastructure while continuing to pursue sustainable local development. Minamiaiki offers an interesting example of the coexistence of traditional rural life, dramatic mountain scenery, and advanced energy infrastructure.
Minamiaiki Village can be reached by turning off National Route 141 toward the village. Because the area is mountainous and private cars are the principal means of transportation, driving is generally the most convenient way to explore the region.
However, the high elevation brings heavy snowfall during winter. Roads may be closed from around mid-November through late April, so visitors should check the latest road conditions before setting out.
Ueno Dam in Gunma Prefecture is the lower reservoir of the Kannagawa Power Station. The shortest route from Minamiaiki requires descending from the village, passing through neighboring Kitasaki Village, and crossing Budo Pass on Prefectural Route 124.
A tunnel beneath Mount Osutaka also connects the Minamiaiki Dam area with the Gunma side, but as of 2024 it remains closed by gates and cannot be used by ordinary vehicles. Travelers should therefore plan their route carefully.
Minamiaiki Village is a distinctive destination where pristine mountain scenery coexists with one of Japan’s most remarkable hydroelectric facilities. The spectacular views around Minamiaiki Dam and Oku-Mikawa Lake, the artistic Uzu-maku Hiroba, and the parks surrounding the dam provide visitors with a fascinating combination of nature, engineering, and local community life.
With its changing scenery throughout the year and its quiet mountain atmosphere, Minamiaiki is an ideal place to step away from busy urban life and reconnect with nature. A visit here offers a peaceful glimpse into a different side of rural Japan, where the landscape and the lives of its people continue to exist in close harmony.