On hot summer mornings, the lake is calm, wrapped in a blanket of morning mist. It is a sign that another scorching day is beginning.
The hot days continue, with no signs of an evening shower yet.
During the day, fawns rest quietly in the shade, and wild birds gather at the water’s edge to cool off.
Ryugu Cave: Sacred Rain-Praying Site and Morning Light Beams
In the Jukai forest lies Ryugu Cave (Ryugu Doketsu). In olden times, people visited this sacred cave to pray for rain.
Rainfall from above ground slowly filters through the lava rock and keeps dripping into the cave. Because of the cool, moist air inside, the water never fully evaporates, keeping the cave perpetually damp.
During clear summer mornings, cool mist rises from the cave entrance. When the early sunlight hits the mist, it creates beautiful beams of light.
Ryugu Cave is a National Natural Monument. Entry inside the cave itself is restricted to protect the environment, but you can view the entrance and the small shrine from the designated path.
To catch the morning light beams in midsummer, the best time to visit is on a clear morning between 7:30 AM and 8:30 AM.
Since the first sightseeing bus arrives after 9:30 AM, taking a taxi or driving is recommended for this early hour. Limited parking is available near the trailhead.
Saiko Bat Cave: Geological Exploration Through the Forest Trail
From Ryugu Cave, a peaceful trail through the Jukai forest leads to the nearby Saiko Bat Cave (Saiko Komori Ana).
For a detailed route map of the Jukai forest, please refer to:
Here, you can observe a rich variety of volcanic formations, such as lava stalactites, lava domes, and ropey lava. Unlike the busier Wind and Ice Caves in the area, it offers a much quieter and more relaxed experience to explore at your own pace.
Saiko Bat Cave
Opening Hours: 9:00 AM – 3:45 PM (Closed from December to March for bat hibernation)
Admission: 350 yen