The pond's entire volume is estimated to be replaced by fresh spring water roughly once every 24 hours.
It is designated as a protected site within the Echigo Tsumari region, famous for the collaborative Triennale art festival.
The water is considered 'soft' and is frequently collected by locals for drinking and brewing tea due to its mineral profile.
The name 'Ryugakubo' translates to 'Dragon's Cave,' stemming from regional folklore about a dragon living in the spring.
The surrounding forest consists of old-growth Japanese cedars that create a unique microclimate cooler than the surrounding village.
Ryugakubo is a natural spring located in Tsunan, Niigata, recognized as one of the 100 Remarkable Waters of Japan by the Ministry of the Environment. It produces approximately 43,000 tons of spring water daily, maintaining a constant temperature of roughly 8 degrees Celsius year-round. The water source is a pond surrounded by dense Japanese cedar forests and indigenous vegetation. The site is associated with a local Ryujin (dragon god) legend, reflected in the presence of a nearby shrine. The water is used for local agriculture, specifically feeding the high-quality rice paddies in the surrounding valley. The area features maintained walking paths through the woods leading to the edge of the pond. Visitors can access the water directly at designated points near the spring's output. The site remains a significant geological feature within the Tsunan Geopark area.
The wooden viewing platform on the northern edge of the pond, which offers a clear reflection of the surrounding cedar trees.
Bring a clean, empty container if you wish to collect and taste the natural spring water directly.
Wear comfortable, closed-toe walking shoes as the woodland paths can be damp or muddy after rainfall.
Carry insect repellent during the summer months, as the dense forest environment near the pond attracts mosquitoes.
Do not attempt to swim or wade into the pond, as it is a protected water source for the local community and strictly prohibited.
Access may be limited or difficult during deep winter months due to heavy snowfall in the Niigata region.
Maintain a quiet volume to respect the local shrine grounds; do not wash feet or equipment directly in the pond to protect water quality.
