Kibikojima

…In the southern part of Okayama Prefecture, facing the Seto Inland Sea, this peninsula stretches from east to west, embracing Kojima Bay. As the name Kibi-kojima appears in the creation myth in the Kojiki, it was an island until the 16th and 17th centuries, but it became connected to the mainland due to sedimentation by the Takahashi River and Asahi River, and reclamation of the shallow sea. After it became a peninsula, the Seto Inland Sea route was shifted to the south shore, and Shimotsui and Hibi flourished as port towns. …

*Some of the terminology that refers to "Kibigojima" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…岡山県南部，瀬戸内海に面し，児島湾を抱いて東西にのびる半島。《古事記》の国生み神話に〈吉備児島〉とあるように16～17世紀まで島であったが，高梁（たかはし）川，旭川などの堆積作用と，浅くなった海の干拓により本土と結びついた。半島になってからは瀬戸内海航路が南岸へ移り，下津井，日比（ひび）が港町として栄えた。…

※「吉備児島」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