Lake Biwa is a lake in Shiga Prefecture that has the largest area and water storage capacity in Japan. It’s one of the world’s ancient lakes that has existed for over 100,000 years. The lake is a Ramsar registered wetland. Under the River Law, it’s designated as a first-class river belonging to the first-class Yodo River Water System, and the law refers to it as first-class river Lake Biwa. This is more than a technicality – the water of the lake has a significant north to south current in some places.
Lake Biwa occupies one-sixth the area of Shiga Prefecture, and the waters flowing through the system have various names including the Seta River, Uji River, and Yodo River, before they reach Osaka Bay on the Seto Inland Sea. The lake water is used as the water supply for communities in the Yodo River basin, and Kyoto city draws water from Lake Biwa through a canal.
The body of water to the north side of Lake Biwa Bridge across the narrowest part is called the North Lake, and the southern part is called the South Lake. The North Lake has an area of 623 km2 and an average water depth of 41 m. The South Lake has an area of 58 km2 and average depth of 4 m. The deepest water is slightly north of the centre of the North Lake, south of Chikubu Island at 104 m. The bottom of Lake Biwa is sinking at a rate of 1 m in 1,000 years.
In addition to supplying water to the Kinki region, it has also been used as a water transportation route since ancient times, for moving goods from Kyōto and Ōsaka to eastern Japan and the Hokuriku region until railways were developed in the Meiji period.
Lake Biwa is the fourth oldest lake in the world. It’s home to more than fifty endemic species such as fish and bottom-living animals. From the Meiji to the early Showa period, there were about forty large and small subsidiary lakes around Lake Biwa, providing an ecosystem for many creatures. Water control projects since then brought changes to the shape of the lake which proved to be less than desirable. These changes are gradually being reversed to restore ecosystems and improve water quality.
Lake Biwa was formed about 4 to 6 million years ago. It was a tectonic lake formed by crustal movements. Its original location was in Mie Prefecture. The lake gradually moved to the north and reached its current position about one million to 400,000 years ago, stopped by the Hira mountain range. The current position of Lake Biwa was a mountain range, and the Suzuka Mountains had not yet risen. The rivers that now flow into southeastern Lake Biwa then flowed into Ise Bay. Lake Biwa is considered to be the oldest ancient lake after Lake Baikal and Tanganyika.
Lake Biwa has been used as a transportation route since the Jōmon period, and vessels such as dugout canoes have been excavated. In ancient times, it was given the name “freshwater sea near the capital”, and it was from this that the name of the region Ōmi arose. It was poetically referred to as the “sea of grebes”.
Lake Biwa forms a choke point between eastern and western Japan, and since early times, gates built on the roads around the top and either side of the lake controlled commerce and the movement of people. Castles were built around the lake using the subsidiary lakes as extensive moats.
Lake Biwa was used as a transportation route for annual tribute to China from Wakasa Bay on the Japan Sea Coast, and there are records of attacks by pirates on the lake. There were various transportation routes from Kyōto to the north using the roads around Lake Biwa’s shores. Cargo was also transported on the lake, and Ōtsu and Katata developed as port towns.
During the Warring States period, Toyotomi Hideyoshi provided a shipowner in Ōtsu with a large fleet of ships. He was placed under the authority of the Commissioner of Ships at Kanon-ji and was given privileges and protection. In the early Edo period, Ōtsu stood in opposition to other ports such as Matsubara, Maibara and Nagahama, which were protected by the Ii clan as the “three ports of Hikone”. Later in the period, the surveyor Inō Tadataka surveyed the shores of Lake Biwa from August to October 1805. The shape of the lake was seen to be similar to that of a type of lute called biwa, and the name Lake Biwa was established.
Goods were transported by water from Ōsaka Bay via the Yodo River and up to Wakasa Bay on the Sea of Japan, with stops at Ōsaka and Kyōto. This method of transport thrived into the early Meiji period, but with the development of land transport, it gradually declined. During the period of high economic growth after WWII, a canal was conceived linking Lake Biwa to the Sea of Japan, the Pacific Ocean, and the Seto Inland Sea. After much planning and coordination between the relevant Prefectures, the idea was finally dropped in 1970.
The ecosystem of Lake Biwa is diverse, with over 1,000 species of animals and plants. Due to its isolation over a long period of time, many endemic species have been identified that live only in Lake Biwa and its water system. It’s a large body of water and unique fisheries developed here.
Ferries ply back and forth between ports around the lake and its several islands. The ferry journeys, with views of surrounding mountains such as Mt. Ibuki, are as rewarding as the time spent on the islands.
Fishing, birdwatching, and photography are pastimes that are more than adequately catered to.
Lake Biwa presents a huge field for adventure activities. Boating, SUP, kayaking, windsurfing, and kite boarding can all be enjoyed on the lake. The roads around the lake are ideal for cycling, and riding around the whole lake in a day is a challenge for determined cyclists.