Biei Blue Pond

The pond was not designed. After the 1988 eruption of Tokachidake, works were built along the Biei River to hold back future mudflows, and water collected behind one of the dams in 1989, drowning a stand of larch that is still standing dead in the water. The colour is the reason people come: aluminium hydroxide carried down from the Shirogane hot springs stays suspended in the water and scatters light so that the pond reads as a flat opaque turquoise, changing with the light and the angle. It is small - a walk around the accessible side takes fifteen minutes - and became internationally known after one photograph of it was distributed as a desktop wallpaper. In winter the pond freezes and is lit at night. The colour is genuinely unnatural-looking and also genuinely there.

What you'll find

• An accidental pond - water collected behind a 1989 mudflow control dam.
• Dead larch - the drowned stand still standing in the water.
• The turquoise - aluminium hydroxide in suspension scattering the light.
• Winter lighting - the frozen pond illuminated after dark in the cold months.

When to go

June to October for the colour; winter for the illumination. An hour.

Good to know

It is small and the visit is short - fifteen minutes covers it. Crowds and coach parties are heavy through summer. The colour flattens in dull weather and after heavy rain. There is little else at the site beyond a car park and a kiosk.

Nearby

Shirahige Falls is up the road at Shirogane; Biei's hills are north.

Key facts