Lake Biwa

▶Japan's Largest "Lake"
Lake Biwa has an area of approximately 670 km². The length of the shoreline is about 235 km. However, if you travel along the roads, it would take around 200 km, and one can cycle around it in roughly two days. The deepest point in Lake Biwa reaches about 104 m. The lake stretches about 60 km from north to south and has a maximum width of about 20 km from east to west.
The volume of water in Lake Biwa is roughly 27.5 billion tons, which is equivalent to about 11 years' worth of water consumption for the 14.5 million people living in the Yodo River basin that utilizes the lake's water.

▶A Rare "Ancient Lake" in the World
Lake Biwa is one of the oldest lakes in the world. It originated around 4 million years ago as a shallow and narrow lake near present-day Iga City in Mie Prefecture (Lake Oyamada). Over time, it has changed shape and moved due to tectonic activity and the filling of depressions with sediment, eventually becoming the lake we know today. Lake Biwa has remained in its current location for at least 400,000 years.
Typically, lakes disappear due to sedimentation in about 10,000 years, making lakes like Biwa, with a history of over 100,000 years, extremely rare. There are only about 20 ancient lakes in the world with a history of over 100,000 years and endemic species, and Lake Biwa is the only one in Japan.

▶A "Treasure Trove" of Life
Over the long span of about 4 million years since the original ancient Lake Biwa and around 400,000 years since the current lake took shape, some of its organisms have undergone unique evolution, resulting in species that exist only in Lake Biwa. It has been reported that over 1,700 species of aquatic plants and animals inhabit Lake Biwa, with more than 60 of these being endemic species.

▶A Lake for Swimming and Play
Lake Biwa is a popular destination for water sports such as sailing and canoeing, with approximately 700,000 visitors each year to its beaches and marinas. The shoreline has many flat paths, making it suitable for cycling and walking. The "Biwaichi" allows you to experience the vastness of Lake Biwa by cycling around it.