Lake Tazawa is the deepest lake located in Senhoku, Akita Prefecture. It is the 19th largest lakes in Japan. It has a beautiful green water and chosen as 100 best Japanese views. It is about 6km long circle lake and the deepest point 423.4m that make it also 17th deepest lake in the world. The altitude of this lake is 249m from the sea level. Therefore, the deepest point is 174.4m below the sea level. Because of this depth, this lake never is frozen in the winter. Also, the color of the water will change from green to blue.

There is a legend of Tatsuko, the woman who became a dragon of this lake and married with Hachiro.