Lake Biwa is the largest lake
in Japan, and is at the center of Shiga Prefecture.
It is called "Biwako" in Japanese.
It is a fresh-water lake, and has an area of about 670 square
The lenght from north to south is about 80 km, and the length at the widest part from east to west is about 25 km.
The altitude of the surface of the lake is about 84 meters, and the depth is about 103 meters.
It is the largest lake in Japan, but it is one of small lakes
in the world.
However, Lake Biwa is one of only about 20 "ancient lakes" in the world.
Lake Biwa was formed about 4-6 million years ago, and is the third oldest ancient lake, after Lake Baikal (25-30 million years ago) and Lake Tanganyika (20 million years ago).
Therefore, this lake has about 50 kinds of endemic fishes and water
It was designated as a UNESCO Ramsar Wetland in accordance with the Ramsar Convention.
But the recent years has seen a rapid increase in the number of
non-native fish in this lake.
Endemic species are on the decline as they fall prey to non-native Black Bass and Bluegills.
As a result, the lake's ecosystem has drastically changed.
More than 120 rivers flow into this lake, but the river flowing out
from this lake is only Seta River.
It flows out at the southernmost point of the lake, flows through Uji city (The name changes to Uji River there.), flows through Osaka city (The name changes again to Yodo River.), and flows into Osaka Bay.
And Lake Biwa Canal was constructed in 1890 and 1912, and it has sent
the water of Lake Biwa to Kyoto city.
We can see a part of the construction of the canal in the site of Nanzenji temple in Kyoto.
There are only five islands in Lake Biwa.
The most popular island of them is Chikubushima island.
To tour around Lake Biwa, some cruise ships are operated.
Otsu Port is near central Otsu city, and the ships cruising around the
south part of Lake Biwa leave from here.
We can enjoy the cruising for 60 or 90 minutes.
And the cruising to Chikubushima and Nagahama in the northern part is operated between May and November. It takes half a day one way, and a day there and back.
And, to tour Chikubushima, the ships are operated from Hikone, Nagahama
It takes about 30-40 minutes one way.
It is a small uninhabited island about 2 km in circle, and is located
about 2 km from the northern coast of the lake.
It is steep and is covered with forest. There is the deepest point of lake Biwa on the west side of the island.
And many ancient earthenwares were found in the bottom of the lake on the west side of the island, and it is unknown why such ancient ruin is there.
On the island, there are Tsukubusuma Shrine (or Chikubushima Shrine)
founded in 420 and Hogonji temple founded in 724.
Main shrine of Tsukubusuma Shrine and Karamon gate of Hogonji are designated as national treasures.
Most buildings of Hokoji are also designated as national important cultural properties.