The pond's water maintains a constant temperature of approximately 16 degrees Celsius throughout the year.
The water is sourced from an underground limestone aquifer, contributing to its high clarity.
The pond has been officially recognized as one of the '100 Famous Waters of the Heisei Era' in Japan.
Local belief associates the pond with Benzaiten, the Buddhist goddess of water and music, due to the nearby temple.
The pond is classified as a 'Fuki-dashi' type spring, where water emerges directly from rocky terrain.
Izuruhara Benten Pond is a natural spring-fed body of water in Sano, Tochigi, designated as a Prefectural Natural Monument. The pond is fed by a high-volume subterranean spring, resulting in water so clear that the bottom is visible through the surface. It is home to a large population of koi fish, including rare specimens, which are protected by the local community. The site is adjacent to the Isoyama Benten-do, a historic temple hall perched on a rocky cliff overlooking the water. The surrounding area is part of the designated karst topography of the region. The spring water is officially recognized as one of the 100 Remarkable Waters of the Heisei Period by the Ministry of the Environment. The water maintains a relatively constant temperature year-round due to its deep-earth origin.
From the wooden boardwalk viewing area, looking toward the red temple structures above the water.
Bring a polarized lens for your camera to eliminate water surface glare and capture the koi clearly.
Prepare for a short, slightly steep climb if you intend to visit the Isoyama Benten-do temple hall above the pond.
The site is compact; combine this visit with a meal of local Sano-style ramen in the nearby city center.
Do not attempt to enter the water or touch the fish, as the area is protected as a natural monument.
Do not feed the koi, as the water's ecosystem is strictly regulated.
