If you stand on Shirogane Bridge, which runs across Biei River, in the middle of the Shirogane Hot Springs area, and look upstream, you will see a waterfall on the right side.

This waterfall is called Shirahige no taki, or 'White Beard Waterfall.'

Much of the water from Shirahige no taki waterfall flows from the nearby cliffside (see the upper left-hand side of the above photo).

The water flows out from the cavity between various layers of rock, the cavity being a throughway for subterranean water to reach the surface.

These rock formations, situated above the mouth of the waterfall, and known as 'columnar joints,' formed approximately 200,000 years ago, from the lava flowing out of the Mt. Tairagadake volcano (located 600m to the northeast of Mt. Tokachidake).

Columnar joints consist of many vertical columns of rock, formed by lava, when it cools and contracts.

Just below the mouth of Shirahige no taki, there is a rounded gravel formation.

This formation, formed from an accumulation of gravel, and other debris from Mt. Tokachidake and other nearby volcanoes, was formed long before the eruption of Mt. Tairagadake.

Additionally, notice that the water of the nearby Biei River is blue (see photo below)

The Shirinashizawa River and the Iouwagawa River, which flow out from Mt. Tokachidake, upstream from Shirahige no taki, merge into the Biei River.

Within this water, flowing from the volcano, are extremely small particles of aluminum silicate (approximately 1/10,000 to 1/1,000,000 of a millimeter). These particles absorb red light, and produce blue light, through a phenomenon known as 'scattering.' This blue light is what gives the Biei River its blue appearance.