Bisan Islands

A group of islands scattered in the Bisan Seto Strait between Okayama and Kagawa prefectures in the center of the Seto Inland Sea. It consists of 165 islands, including Shodo Island, the second largest island in the Seto Inland Sea from the east, Toyo Island, Ogi Island, Megi Island, Ozuchi Island, Mutsukuchi Island, the Naoshima Islands (Naoshima, Mukae Island, Iejima, Ushigakubi Island, etc.), the Shiwaku Islands (Honjima, Ushijima, Hiroshima, Teshima, Hitsuishi Island, Yojima, Takami Island, etc.), and the Kasaoka Islands (Kitagi Island, Shiroishi Island, Manabe Island, etc.). Most of the islands belong to Kagawa prefecture, except for the Kasaoka Islands and Mutsukuchi Island, which belong to Okayama prefecture. The prefectural border between Kagawa and Okayama originates from the border determined by the shogunate in the Edo period when the people of Shimotsui and Shiwaku Islands fought over fishing grounds. Maritime traffic has been active in the Bisan Seto Strait since ancient times, and many of the islands prospered as ports of call for sailing ships. The Shiwaku Islands in particular were famous for their navy, and the islands were granted autonomy under the ninmyo system, granted by Toyotomi Hideyoshi and Tokugawa Ieyasu, and were active on the Kitamae route, with Ushijima owning sailing ships totaling 50,000 koku in the early Edo period. Fishing and field farming have been practiced here, but many of the islands are included in the Seto Inland Sea National Park, and Hitoshi, Iwakuro, and Yoshima in the Shiwaku Islands are located on the Kojima-Sakaiide route (Seto Ohashi Bridge) of the Honshu-Shikoku Bridge, and tourism development is also progressing.

[Yoshiaki Sakaguchi]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

瀬戸内海の中央部、岡山・香川両県間の備讃瀬戸に点在する島嶼(とうしょ)群。東から瀬戸内海第二の島小豆(しょうど)島をはじめ、豊(て)島、男木(おぎ)島、女木(めぎ)島、大槌(おおづち)島、六口(むくち)島、直島(なおしま)諸島（直島、向(むかえ)島、家(え)島、牛ヶ首島など）、塩飽(しわく)諸島（本島、牛島、広島、手島、櫃石(ひついし)島、与(よ)島、高見島など）、笠岡(かさおか)諸島（北木(きたぎ)島、白石(しらいし)島、真鍋(まなべ)島など）など165の島々からなり、岡山県に属す笠岡諸島、六口島などを除いて、大部分の島が香川県に属す。香川と岡山の県境は、江戸時代、下津井(しもつい)と塩飽島民の漁場争いでの幕府裁定の境界線に由来している。備讃瀬戸は古くから海上交通が盛んで、帆船の寄港地として繁栄した島々も多い。とくに塩飽諸島は水軍で名高く、豊臣秀吉(とよとみひでよし)、徳川家康(とくがわいえやす)から朱印状を得て、人名(にんみょう)制という自治が許された島々で、北前航路でも活躍、江戸時代前期、牛島は計5万石の帆船を所有していた。漁業、畑作農業が営まれてきたが、瀬戸内海国立公園に含まれる島々も多く、塩飽諸島の櫃石、岩黒(いわくろ)、与島などは本州四国連絡橋児島(こじま)―坂出(さかいで)ルート（瀬戸大橋）にあたり、観光開発も進んでいる。

［坂口良昭］

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