Kogoishi - Kogoishi

An ancient stone-lined ruin. The name arose from the rectangular cut stone rows that surround about one-third of the mountain midway up Mount Kora in Kurume, Fukuoka Prefecture, and later came to refer to similar ruins as well. During the Meiji and Taisho periods, the area was also called "Kogoseki," and with the location of the Shikinaisha shrine Kora Taisha on the mountainside, there was a heated debate in academic circles between the theory that the rows of stones defined a sacred area, which claimed it was a sacred area, and the theory that it was an ancient fortress, but it is now considered a type of fortress. One theory also says that the shape of the rows of stones resembles a leather basket, and so they were likened to a sacred basket.

At Otsuboyama in Takeo City, Saga Prefecture, rows of closely packed cut stone are piled up in two or three tiers around the middle and base of a low hill (66 meters above sea level), with earthworks built on top. In front of these are rows of post holes and cornerstones spaced at roughly equal intervals. At the saddle of the hill, rows of stones are lined up on the inside and outside, and an earthwork made of tamped earth is built on top. At the mouth of the valley, rows of stone walls and a culvert sluice gate are built, and overall the structure resembles an ancient Korean-style mountain castle from the 7th or 8th century.

Currently, there are 13 known locations for Kogoishi, including the two mentioned above, Obukumayama in Saga Prefecture, Zoyama, Haki, Raizan, Goshogatani, and Kageno-ma in Fukuoka Prefecture, Iwakisan in Yamaguchi Prefecture, Einoyama in Ehime Prefecture, Kinojo and Omegurikomeguriyama in Okayama Prefecture, and Kiyama in Kagawa Prefecture, which has a similar structure. The purpose of their construction is not recorded in any written records, and the date is unclear. There are various theories, including that they were fortresses from the 6th century that preceded the ancient Korean-style mountain castles, and that they were fortresses from the 7th or 8th century, and there is still no consensus.

[Otomasu Shigetaka]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

古代の列石遺構。その名称は福岡県久留米(くるめ)市高良山(こうらさん)の中腹付近に、全山の約3分の1を取り巻くように長方形の切石(きりいし)列が巡ることからおこり、のち類似の遺構をも称することになった。明治・大正のころは「こうごせき」ともよばれ、山の中腹に式内社高良大社があることから、列石で神域を画定したとなす聖域説と、古代城塞(じょうさい)説とが対立し学界をにぎわせたが、いまでは城塞の一種とみられている。また一説では、列石の形が皮籠(かわご)に似ていることから、神籠に擬したともいう。

　佐賀県武雄(たけお)市おつぼ山(やま)では、低い丘（標高66メートル）の中腹や丘裾(すそ)を巡って、密に接した切石列石を2、3段に積み、その上部に土塁を築く。それらの前面にはほぼ等間隔に柱穴列や礎石列の並ぶものがある。丘の鞍部(あんぶ)には内側と外側に列石を並べ、上部には版築(はんちく)による土塁を築く。谷口には石垣列と暗渠(あんきょ)水門を設け、全体に7～8世紀の朝鮮式古代山城(やまじろ)に似る。

　神籠石は、現在、前記2か所をはじめ、佐賀県帯隈山(おぶくまやま)、福岡県の女山(ぞやま)、把木(はき)、雷山(らいざん)、御所ヶ谷(ごしょがたに)、鹿毛馬(かげのま)、山口県石城山(いわきさん)、愛媛県永尾山(えいのおやま)、岡山県の鬼城(きのじょう)、大廻小廻山(おおめぐりこめぐりやま)のほかに、類似した構造をもつ香川県城山(きやま)を含めると13か所が知られている。これらの築造目的は文献記録にもなく年代も明らかでない。一説には朝鮮式古代山城に先行する6世紀代の城塞説や、7世紀または8世紀の城塞説などまちまちで、いまだに定説をみない。

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