[Akita] Water depth 423.4m! Japan's deepest lake "Lake Tazawa"

NEFT Editorial Department
2016.09.12
Last updated: 2025.08.19

table of contents

1 Lake Tazawa, Japan's deepest lake
2 The indigo lake surface known as Lake Tazawa Blue
- 2.1 INFORMATION

Lake Tazawa, Japan's deepest lake

Lake Tazawa, located in Senboku City, Akita Prefecture, is the deepest lake in Japan. With an area of 25.8 square kilometers, it is the 19th largest lake in Japan, so it is not particularly impressive in terms of size. However, with a maximum depth of 423.4 meters, it is well known nationwide

It is so deep that if Japan's tallest structure, the Skytree, were submerged, it would even submerge the second observation deck. Unlike ordinary lakes, it does not freeze even in the middle of winter. It has been selected as one of Japan's 100 most scenic spots, and the entire lake is included in a prefectural natural park. The lake's name comes from Tazawako Town, which existed from 1956 to 2005

The indigo lake surface known as Lake Tazawa Blue

The beautiful blue color, like flowing blue ink, is called Lake Tazawa Blue, and is vivid yet transparent. The depth varies depending on the location, and the angle of the sunlight shining in also changes, resulting in colors ranging from jade green to deep indigo

The water used to be clearer than it is today, but as oxidation progressed, several species of living creatures became extinct. Measures were taken to neutralize the water, such as releasing lime and Japanese dace into the lake, but these measures were not very effective. The kunimasu and kokanee salmon that lived there until 1940 are no longer around, but a survey in 1948 revealed that new fish such as Japanese dace and white-spotted char had begun to inhabit the lake. The water quality has not changed since then, so visitors to Lake Tazawa in the future will be able to observe Japanese dace and white-spotted char swimming leisurely by simply peering into the lake's surface

One of the legends surrounding Lake Tazawa is the Legend of Tatsuko. Long ago, there was a girl named Tatsuko who, wanting to preserve her beauty forever, made 100 pilgrimages to the shrine. On the night of her 100th pilgrimage, a god appeared and told her to drink from the spring in the north. After drinking a large amount of the spring's water, Tatsuko turned into a dragon, and her rampage caused a mountain to collapse, creating Lake Tazawa. According to legend, the dragon eventually sank deep to the bottom of the lake and became the lord of Tazawagata. There are many facilities in the surrounding area related to this legend, which can be said to be the roots of Lake Tazawa. This is a tourist spot where you can easily see statues such as the Tatsuko Kannon statue and the Hime Kannon statue, which depict the childlike appearance of the young girl