Because the water of the blue pond is blue, there is a water containing aluminum from “Whitebeard Falls” in the Shirokane Hot Spring area. (The waterfall is a submersible basin where groundwater flows up from the middle of the cliff.) When this waterfall mixes with the water of the Biei River, invisible colloidal particles are generated, which scatter the sunlight evenly. (From the bottom of the Biei River 滝 waterfall. Alias: also called Blue River.) Because the short wavelength blue light is easily scattered, it reaches the eye and looks blue. ※ Water looks blue when viewed from land, but no color is seen in the water itself. ※ Colloid refers to the state in which particles of one substance are dispersed in another substance. further! ! The platinum hot spring water suspended from the side of the waterfall seems to make the rocks and rocks of the bottom of the river whiter and further enhance the blueness of the water, as the sulfur and lime components help scatter the light.

Access: About 20 minutes by car from JR Biei Station. About 20 minutes by Dokita Bus.
Parking lot: Yes
Fee: Admission free