Lake Biwa

Lake Biwa fills the basin of Omi in central Japan. Its waters drain south through the Seta River toward Kyoto and the Yodo system, while roads along both shores connect the Japan Sea provinces with the capital. Fishing, reed gathering and cultivation supported lakeside settlement; boats carried rice, timber, salt and other bulky goods more cheaply than carts, giving the lake a place in the provisioning of Kyoto.

Buddhist foundations and warrior houses competed for its ports and revenues. In 1576 Oda Nobunaga began Azuchi Castle on the eastern shore, using the lake route and Omi's roads to control movement toward Kyoto. After his fall Toyotomi Hideyoshi reorganised the crossing and in 1587 established the Otsu hundred-boat group to regulate shipping. Castle towns and post stations grew where land routes met the water.

Under the Tokugawa shogunate, Lake Biwa remained a commercial artery. Rice from northern provinces, fish from lakeside villages and goods bound for Osaka moved through Otsu and Hikone. Omi merchants extended family trading networks across Japan, joining local fisheries and farms to national politics, religion and commerce.