Okinoshima (Water Town) - Okinoshima

...The area stretches along the coasts of the Tone River, Yokotone River, Kitatone River, Lake Kasumigaura, Sotonasakaura, and Kitaura, and is designated as Suigo-Tsukuba Quasi-National Park. In ancient times, this flowing sea was called the Katori Sea, and in the Middle Ages, islands in the river such as Okinoshima were formed by sedimentation of the Tone River system. In the early modern period, after the Tone River was redirected, land was rapidly developed, and new rice fields such as Jyurokushima were developed. Jyurokushima, the center of the waterway, once had waterways called Enma dug in all directions, which were used for irrigation, drainage, and transportation.

*Some of the terminology that refers to "Okinoshima (Suigo)" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…利根本流，横利根川，北利根川，霞ヶ浦，外浪逆浦（そとなさかうら），北浦の沿岸に広がり，水郷筑波国定公園に指定されている。古代には香取海といわれた流海で，中世に利根川水系の堆積作用で沖之島などの川中島が形成され，近世初期の利根川の河道付け替え以後急速に陸化が進み，十六島（じゆうろくしま）などの新田開発が進展した。水郷の中心の十六島はかつてはエンマという水路が縦横に掘られ，灌漑，排水路として，また交通路として利用された。…

※「沖之島（水郷）」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報