Knowledge of Toyako Onsen

The third largest caldera lake in Japan

The beautiful Lake Toya is located in the center of Shikotsu-Toya National Park. It is Japan's third largest caldera lake, after Lake Kussharo and Lake Sikotsu, which are also Hokkaido.

Lake Toya was created approximately 110 thousand years ago, due to a giant volcanic eruption. It has a circumference of approximately 43 km (36 km by road) and is 84 km above sea level, with a surface area of 70.7k㎡. The lake is the northernmost lake in Japan that never freezes in the winter, although with the recent extreme cold temperatures, one area of the lake has started to freeze over.
The four islands (Oshima, Bentenjima, Kannonshima, and Manjujima) in the center of Lake Toya are said to be solidified lava domes created through volcanic eruptions that occurred at the bottom of the lake about 50 thousand years ago. Collectively, the islands are known as Nakajima.
Lake Toya is flanked on its northern side by the beautiful peak of Mt. Yotei, and on its southern side by the volcano Mt. Usu and volcanic lava dome Showa Shinzan. The lake offers a dynamic variety of scenery during each of the four seasons.

An onsen town close by Lake Toya that celebrated its 100 year anniversary as an onsen in 2010

The sources of Lake Toya Onsen and Sobetsu Onsen are closely connected to the activity of Mt. Usu. Their origins as natural springs is clear, which is something rather unusual for hot springs.

With the 1910 (Meiji 43) eruption of Mt. Yosomi, some parts of the neighboring lake rose in temperature to 24℃ as the ground lifted. Toya Onsen is said to have been born after the volcanic activity died down, when gushing hot springs of 42℃ were discovered in the lake waters at the northern foot of Mt. Nishimaru. In 2010, the onsen celebrated its 100-year anniversary by holding various events.

According to the histories of Abutacho, in 1917 (Taisho 6), seven years after the eruption of Mt. Yosomi, Lake Toya Onsen opened for business, as did other onsen accommodations in the area.

Knowledge of Toyako Onsen

Beautifying waters that make your skin silky smooth

Lake Toya Onsen has twelve source wells from which spring waters rise from a depth of 60–150 meters.

The waters include sodium and calcium hydrogen-carbonate springs, sulphate springs, and chloride springs and are reputed to be effective for treating neuralgia, muscle pain, joint pain, cold extremities, burns, scars, and so on.
In particular, the hydrogen-carbonate springs soften the surface of the skin
and emulsifies and washes away fat and secretions. These waters are known as "springs for beauiful women" or "springs for beautiful skin" due to their ability to make the skin soft and smooth.

Some theories suggest that the effects of the spring waters improved after the eruption of Mt. Usu in 2000.