Time Required: 2 h 48 min. Distance: 131.6 km
This course takes you on a drive around the park’s three renowned lakes—Lake Akan, a famous marimo (lake balls) habitat; Lake Mashu, which is often covered in mist; and Lake Kussharo, which has many lakeside rotenburo (outdoor baths). Set off from Lake Akan’s shore on the Akan-Mashu Odan Road. After stopping at the Sokodai Observatory, where you can look out at Mt. O-akan and the two lakes in the special protection zone (Lake Panketo and Lake Penketo), head over the pass to enter the Mashu area. From the town of Teshikaga, climb to the Mashu Caldera where you will find Lake Mashu, famed for the mist that floats over its waters. Gazing down from Lake Mashu Observatory 1 will allow you to look over the lake. Once you descend from Mashu Caldera, head toward Mt. Mokoto. After taking in the view of Lake Kussharo from Mt. Mokoto Observatory and Highland Koshimizu 725, enjoy Sunayu and Kotan Onsen, both of which are hot springs along Kussharo’s lakeside. Upon finishing the course at the Bihoro Pass Observatory, you will have experienced the national park’s three exemplary lakes.
Old Akan Lake was formed by volcanic activity 100,000 to 150,000 years ago, but afterwards between 6,000 and 10,000 years ago, volcanic activity from Mt. O-akan split the lake up into the present-day Lake Akan, Lake Panketo, and Lake Penketo. The hot spring resort on the shores of Lake Akan has been a lively area since long ago and continues to be so to this day. By taking a sightseeing cruise boat, you can visit scenic spots, such as Takiguchi or Chuurui Island, where you can see the marimo (lake balls). Lake Akan is the only place in the world where large-sized marimo can live and they are said to be the result of a series of coincidences involving the lake’s unique and complex geography, the spring water that stimulates their growth, and the wind and wave conditions.
Created by a powerful eruption around 7,000 years ago, the Mashu Caldera is home to Lake Mashu, which boasts the second clearest water in the world. Lake Mashu is known for the thick mist that often hangs over the water’s surface. Looking out, you can see Kamuinupuri (Mt. Mashu’s name in the Ainu language), while in the center of the lake sits Kamuishu (the Ainu name for Nakajima Island). An Ainu legend about the island tells of an old woman who got separated from her grandchild when fleeing violence between two kotan (Ainu villages). Looking for the child, she lost her way and became so heartbroken and weary that she could no longer move, eventually turning into Kamuishu (Nakajima Island).
Kussharo Caldera was shaped by a massive eruption that occurred around 100,00 to 130,000 years ago. Lake Kussharo, located at its center, is the largest caldera lake in Japan. Volcanic activity continues around the lake to this day, which is evident in spots like Sunayu, where hot water wells up if you dig in the sand, and at Oyakotsu Jigoku ("Oyakotsu Hell") on the Wakoto Peninsula. Although the lake freezes over completely in winter, geothermal heat melts the ice, so every year between 400 and 500 swans visit the area. Not only does Bihoro Pass have one of the greatest panoramic views in Japan, but at the rest house, you can also enjoy the pass’s delicious specialties such as the fried potatoes and soft-serve ice cream made with a type of bamboo grass.