Biwako [Lake Biwa], located in the center of Shiga Prefecture, is the largest freshwater lake in Japan occupying about one-sixth of the land area of the prefecture. Surrounded by lush green mountains and rural scenery to immerse with the water and lush nature. Lake Biwa is said to have four million years of history and is one of the 20 ancient lakes in the world. As the home of over 1,700 species of aquatic plants and creatures, including over 60 endemic species, Lake Biwa is an invaluable natural environment. The lake is also a critical source of water used for daily life and industry not only by residents of Shiga Prefecture, but also by many people living in Osaka, Kyoto, and other parts of the Kansai Region. The tranquil scenery comprised of the lake and the environments let visitors enjoy every moment of each brilliant season.

Biwako [Lake Biwa], the largest lake in Japan, has an area of approximately 670k㎡ and shoreline extending around 235km, maximum depth approximately 104m, and a water storage capacity of 27.5 billion ㎡. Fault activities caused a shallow and narrow lake formed near Iga City, Mie Prefecture called Lake Oyamada to gradually changed shapes and moved up north and became Biwako [Lake Biwa]. While lakes usually tend to disappear in about 10,000 years due to sedimentation, Biwako [Lake Biwa] has been maintained in current position for about 400,000 years, although being constantly moved for a long period of time. Being only one in Japan of the 20 ancient lakes in the world, and existing for more than four million years makes a global value for Biwako [Lake Biwa].

Down through the ages, some organisms have evolved in their own unique ways, giving rise to many endemic species unique to Biwako [Lake Biwa]. Currently, Biwako [Lake Biwa] is home to more than 1,700 species of aquatic plants, of which more than 60 are endemic, including early endemics such as the "Biwa-Higai" [Sarcocheilichthys variegatus microoculus] and "Sugomoroko" [Squalidus chankaensis biwae], a minnow, as well as relict endemics such as the Biwako giant catfish [Silurus biwaensis] and "Gengorobuna" [Japanese crucian carp]. At the Lake Biwa Museum in Kusatsu City, families enjoy learning about the origins of Biwako [Lake Biwa] and the relationship between people and the inhabitants of the lake.

Especially on weekends and holidays, many visitors from nearby areas gather to Biwako [Lake Biwa] and enjoy camping, BBQ, and other recreational activities. Lake sports, like yachting and canoing, beaches for swimming and marinas are popular and attract about 700,0000 people each year. Biwako [Lake Biwa] is about 235 Km in circumference and is able to be traveled around by bicycle in two days, and the act of cycling or walking around the lake is known as "Biwaichi" (One lap around Biwako [Lake Biwa]). A trip around Biwako [Lake Biwa] is bound for a sense of the size of the lake.