（89）島根県の古曽志大谷1号墳（前方後方墳・破壊後に復元）と
姥ケ谷古墳群
(89) Kososhi-Otani No.1 Tumulus (Posterior frontal tomb, restored after destruction) and Ubagaya Tumulus Group in Shimane Prefecture
島根県の宍道湖北岸の丘陵地に「古墳の丘古曽志公園」がある。
古曽志寺廻田西古墳群・姥ヶ谷古墳群・古曽志廻田古墳群・古曽志大塚古墳群が史跡公園として保存・一部復元されている。
In the hills on the northern shore of Lake Shinji in Shimane Prefecture, there is the Kososhi Park of Kofun-no-oka.
The Kososhi Teramawata West Tumulus Group, the Ubagaya Tumulus Group, the Kososhi-Mawata Tumulus Group, and the Kososhi-Otsuka Tumulus Group have been preserved and partially restored as a historic site park.
その史跡公園の目玉が古曽志大谷１号墳。
The centerpiece of the park is the first Kososhi Otani tomb.
全長45.5ｍの前方後方墳で、築造はAC460-490年ごろ（５世紀後半）。
墳丘は,基本的に尾根頂上の地山を削り出し,
さらにその削った上を盛り上げることによって2段に築成された。
It is a 45.5 meter-long forward and backward mound, built around 460-490 AC (late 5th century).
The mound was basically constructed in two stages by carving out the ground at the top of the ridge and then raising the ground on top of the carving.
前方部から後方部を望む
急峻な45度の斜面
後方部の幅は、24-25ｍ・くびれ部で23m・高さ5ｍ以上、前方部は、長さ20.5m,くびれ部でおよそ21m前後で幅は30m前後と推定され,かなり前方部が発達した形態。
斜面は全体的に急竣で40～45°に達する部分もある
The width of the back part is 24-25m, 23m at the neck part, and more than 5m high, while the front part is estimated to be 20.5m long, 21m at the neck part, and 30m wide.
The slope is generally steep, reaching 40 to 45 degrees in some parts.
階段の手前が造り出し
人頭大の葺石をもち,墳頂や段の上,墳裾には円筒埴輪を廻らしていたと考えられる。
珍しいのは前方部から長さ5.5m,先端部幅9.5mの造り出しがあったことで、
埴輪列と須恵器や土師器片を確認。
It has a thatched stone the size of a human head, and it is thought that cylindrical terra-cotta clay wheels were placed on the top of the mound, on the top of the steps, and at the foot of the mound.
What is unusual is that there is a 5.5m long and 9.5m wide overhang from the front part of the mound, where rows of clay figurines, Sue ware and earthenware fragments were found.
埋葬施設は、後方部は流出したと考えられるが、
前方部墳頂には礫が敷かれており、その下から礫椰が発見された。
棺内からは鉄製大刀1,刀子2,鉄斧、棺外の礫の上から鉄鏃が約40本出土。
The back part of the burial facility is thought to have been washed out, but the top of the front part of the mound was covered with gravel, and gravel palms were found underneath.
Inside the coffin, an iron sword, two swords, an iron axe, and about 40 iron arrowheads were found on the gravel outside the coffin.
この貴重な古墳は、発見当初から学者や市民から保存運動等が起こされたが、団地造成が優先され破壊されてしまったが、のちに200ｍほど東に史跡公園として復元された。
From the time of its discovery, scholars and citizens campaigned for the preservation of this valuable burial mound, but it was destroyed in favor of the construction of a housing complex, but was later restored as a historical site park about 200 meters to the east.
方墳3基がある姥ケ谷古墳群
史跡公園駐車場から階段を上ると方墳3基がある姥ケ谷古墳群を経て
古曽志大谷四号墳の模型、そして古曽志大塚１号墳にたどり着く。
Ascending the stairs from the parking lot of the historic site park, you will pass the Ubagaya Tumulus Group, which has three square mounds, and reach the model of the fourth tomb of Kososhi Otani and the first tomb of Kososhi Otsuka.
眼前に宍道湖が広がる
古墳の頂上からは神が宿る山としてあがめられてきた「朝日山」、
南には「宍道湖」を見渡すことができる。
From the top of the burial mound, you can see Asahiyama, which was revered as a mountain where gods resided, and Lake Shinji to the south.
引用／古曽志遺跡群発掘調査報告書（全国遺跡報告総覧）・神々のふるさと山陰観光ポータルサイト
Reference: Kososhi Site Group Excavation Report (Nationwide Site Report), San'in Sightseeing Portal Site, Home of the Gods
Translation: DeepL Pro