Lake Kuttara

Lake Kuttara is a caldera or crater lake, that is said to be the roundest in Japan. Its surroundings measure approximately 8 kilometers. It is located in Hokkaido and boasts crystal clear water, just like the famous Lake Mashu which renowned for having the clearest water in Japan. The name "Kuttara" is thought to have come from "Kuttarushi," meaning "a place where many Itadori gathers" in the Ainu language. Itadori is a plant of the knotweed family.
Originally there were few living things in the lake, but as a result of the Kokanee salmon eggs being brought in for breeding from Lake Towada and Lake Shikotsu in 1910, the fish can now breed naturally. There is someone that needs to be mentioned when talking about the Kokanee salmon. Her name is Tome Nakao and she moved from Sapporo to the unexplored Kuttara lake area in order to take over the aquaculture business her husband started. Even after shuttering the business, she continued living by the lake, supporting herself by working in forestry and selling charcoal until she died at the age of 63. Tome read English-language books, wore Western clothes popular during the Taisho period and straddled the saddle of a horse when she rode. She is known as "the wife of the swamp,” and her story is now legendary.