Blue Pond

In a forest near Biei in central Hokkaido, dead larch and birch trunks stand upright in water of a milky, almost unreal turquoise. The Blue Pond — Aoi-ike, also known as the Shirogane Blue Pond — looks like a natural wonder, but it is an accident of flood engineering.

In December 1988, Mount Tokachi erupted, and to protect the town of Biei from volcanic mudflows, several barriers were built across the Biei River. One of them, a dam of concrete blocks, was begun by the Hokkaido Regional Development Bureau in June 1989 and completed by the end of that year. Because it extended into the woods on both banks, water collected behind its left-bank section and flooded the trees growing there, which died where they stood. Nobody planned a pond; it simply formed.

The colour is thought to come from fine white particles such as aluminium hydroxide carried by local spring water. When these mix with the river water they form a colloid that scatters sunlight, adding to the blue that water itself transmits. The shade shifts with weather and season, and after heavy rain from Typhoon Mindulle in August 2016 the pond briefly turned brown with mud and sand from the river. Local accounts credit the photographer Masumi Takahashi, of nearby Kamifurano, with finding it in 1997 and making it known through his photo book of 1998. In 2012 a photograph of the pond was chosen as one of the desktop wallpapers for Apple's OS X Mountain Lion, which brought it worldwide attention.

The pond lies at about 500 metres above sea level on the left bank of the Biei River, some 2.5 km northwest of Shirogane Onsen, a hot-spring village at the foot of the Tokachi volcanoes. Biei itself is a farming town known for its rolling, patchwork hills, set between Asahikawa and Furano.

Getting there

The pond is about 18 km from Biei Station on the JR Furano Line and about 2.5 km from Shirogane Onsen. The nearest airport is Asahikawa Airport (AKJ), about 24 km away.