Kibi's Hole Sea

...A bay in the northern part of the Kojima Peninsula in southern Okayama Prefecture. In ancient times, the area between the mainland and the Kojima Peninsula, which was an island, was dotted with many islands and was called Kibi no Anaumi (Kibi Hole Sea). This was the main route for navigation on the Seto Inland Sea. In the early modern period, Kojima was connected to the mainland by the sedimentation of the Takahashi River, Sasagase River, Asahi River, and Yoshii River, and the west side became Achigata Lagoon, and the east side became Kojima Bay.

*Some of the terminology that refers to "Kibi no Anaumi" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…岡山県南部，児島半島北側の湾。古くは島であった児島半島と本土との間は，多数の島が散在し吉備の穴海（あなうみ）と呼ばれ，ここが瀬戸内海航路の主要ルートであった。高梁（たかはし）川，笹ヶ瀬川，旭川，吉井川の堆積作用で近世初頭には児島が陸繫され，西側は阿知潟，東側は児島湾となった。…

※「吉備の穴海」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