Lake Tazawa

Lake Tazawa, in Semboku, Akita, is the deepest lake in Japan. It has a depth of 423.4 meters.
Because of its depth, it does not freeze in the winter. It also drastically changes colors throughout the day, depending on how the sunlight hits the water.
The lake is where the famous legend of Tatsuko takes place. According to legend, Tatsuko, an exceptionally beautiful girl, prayed very hard to retain her beauty, but instead became a dragon and sunk to the bottom of the lake as a punishment of her greed. On the shore, there is a statue of Tatsuko.
By the lake, there are some hot springs ryokan and shops. If you wish, you could also go for an adventure to nearby Mount Akita-Komagatake.