Mount Kurobi, the highest peak of the Akagi complex, was formed from the remains of a dormant stratovolcano.
Akagi Shrine is traditionally associated with the legend of a dragon god inhabiting the depths of Lake Onuma.
The mountain was designated one of the '100 Famous Mountains of Japan' in the seminal work by Kyūya Fukada.
The area is famous for its 'Akagi Oroshi,' a dry, cold seasonal wind that descends from the mountains toward the Kanto Plain during winter.
During the winter months, Lake Onuma freezes over, allowing for ice-fishing for pond smelt.
Akagiyama is a collective name for a group of volcanoes located in central Gunma Prefecture, reaching its highest point at Mount Kurobi at 1,828 meters. The area centers around the caldera-forming Lake Onuma and the smaller Lake Konuma, which serve as focal points for hiking trails and recreational fishing. Akagi Shrine, situated on the shores of Lake Onuma, is a historic Shinto site dedicated to the deity of the mountain. The volcanic plateau features expansive alpine meadows such as Kakumanbuchi, providing habitats for diverse high-altitude flora. Recent observations confirm the area remains open to public hiking, though trails are subject to seasonal weather closures due to heavy snowfall. The caldera basin functions as a significant watershed and ecosystem preserved within the Akagi Prefectural Park.
The red bridge leading to Akagi Shrine with Lake Onuma and the volcanic peaks as the backdrop.
Check the official Gunma Prefecture disaster prevention website for current trail conditions and volcanic activity levels before heading out.
Bring specialized hiking footwear with good ankle support, as volcanic terrain can be uneven and rocky.
Carry layers for wind protection, as temperatures at the summit can be significantly lower than in the surrounding valleys.
Attempting to hike during the late autumn and winter transitions without proper mountaineering gear, as the mountain experiences sudden weather shifts.
Roads leading to the upper caldera are frequently closed or require snow tires from late autumn through mid-spring due to heavy snow accumulation.
Remain on marked trails to protect sensitive alpine vegetation and observe quiet behavior within the shrine grounds.
