Lake Shinji

Lake Shinji lay within the waterways of Izumo, connected eastward through the Ohashi River and Nakaumi to the Sea of Japan. Its western shore changed greatly during the early Tokugawa period. Floods in 1635 sent the Hii River into the lake; after further breaches in 1639 its main current flowed eastward permanently. A river once associated with an outlet toward Taisha Bay now brought water and sediment into the lake basin.

This transformation created both danger and opportunity. Matsue and the lakeshore suffered repeated floods, including the disastrous inundation of 1674 and another great breach in 1702. At the western end, embankments and deliberate changes of the Hii's channel helped reclaim new rice land. The Matsue domain's works fixed the river's eastward course, while successive generations extended cultivation over deposited sediment. Waterways such as the Takase and Hirata Funakawa supported transport through this altered landscape. Lake Shinji's early modern shoreline was therefore continually remade by floods, river engineering and agricultural settlement, as communities sought productive land beside waters that could also sweep their homes away.