Lake Biwa is the largest in Japan. It is located in Shiga prefecture. Since there is always a large amount of water, Osaka City, which is located downstream of the river that flows out of Lake Biwa, never run out of water even when the sunshine continues in the summer.

Lake Biwa is so large that sandy beaches just like the seashore are developed. Therefore, coastal plants and insects are known to live there. The sea bindweed Calystegia soldanella is one of them ,which bloom in pink like a morning glory. But it is a mystery how the coastal species got to Lake Biwa from the coast.

In the bindweed colony, you can see pretty flowers from May to June.