Post by washi on Apr 17, 2015 4:55:18 GMT
This post is about the efforts of my friend, Mr. Toshiyuki Yoneda, and his colleague, Mr. Hisashi Okuda, to locate the outer boundaries of Takayasu Castle, a fortification constructed in 667 A.D. on Mt. Takayasu. Mt. Takayasu is a mountain that forms part of the boundary between modern Osaka Prefecture and Nara Prefecture. Using the traditional place names, the mountain was bounded by Kawachi on the west and Yamato on the east. Prior to their investigation, most of the published literature had located the castle entirely on the eastern (Nara / Yamato) slope. Their investigation establishes a likely western boundary well over the ridge line and into the Osaka / Kawachi area.
The great age of Japanese castle building was in the Civil War Era in the 16th century. Most of the elaborate and majestic structures that we see today are preserved (or much more likely, reconstructed) from that time period or from the later Edo Period, when they were used to enforce the ShÅgun's rule but were little used in actual combat. Few traces of the castles built in the 7th century remain, and for the most part, only their general locations are known. Being merely fortified mountain tops, they are thought to have been much different from the castles built in later times. Although the term "Korean Style Mountain Castles" has fallen out of favor in recent scholarship, the term continues to be used to describe the castles built in Japan in the late 7th century. It is not entirely inappropriate. Prior to that time, there was little need for (and therefore little expertise in) building fortifications, and the Japanese almost certainly relied heavily on the experience of the numerous refugees they were hosting. Indeed, much of the scholarship surrounding castles built at this time is centered on the study of fortifications built at the time on the continent.
Mr. Yoneda and Mr. Okuda published a short book about the undertaking in 2000, and Mr. Yoneda also wrote a magazine article in 1999. The Japanese portion of this file is taken from that article. The English portion is a text translated by him, but expanded by myself, because I have assumed that many of the historical details mentioned will not be familiar to English readers. For my own benefit, as well as for other English readers who may also be unfamiliar with 7th century Japanese history, I have likewise located in the attached .kmz file the important places referred to in this text.
Background of the Construction of the Castle
The following facts are recorded in the Japanese historical chronicles, and are accepted without dispute by most historians: In the year 660 A.D., Kudara (the Japanese name; in English Baekje) was conquered by Shiragi (in English, Silla) and its Tang Chinese ally. Kudara had traditionally enjoyed closer ties with the Yamato court than the other two Korean kingdoms. In 663, the crown prince sent a large force to Korea to restore the kingdom of Kudara. This prince ascended the throne as the Emperor Tenji just a few days after the armada of 800 ships and 42,000 men departed from what is now the city of Osaka. This force was completely destroyed by the Shiragi and Chinese forces in a naval battle at Hakusui no E, said by some to be the greatest defeat of any Japanese force prior to the 20th century. Fearing a counter invasion, the Japanese erected a series of defensive fortifications throughout western Japan, and the imperial seat was moved first to Kyushu and then back to central Japan to a naturally protected site on the shore of Lake Biwa in the present city of Ōtsu, called Ōmi no Miya.
In 666 Nagato Castle was constructed in present-day Yamaguchi Prefecture, Åno Castle in Fukuoka Prefecture, and Kii Castle in Saga Prefecture. In 667 Takayasu Castle was built in Osaka Prefecture, Yashima Castle in Kagawa Prefecture, and Kaneda Castle in Tsushima in Nagasaki Prefecture. Prior to the defeat a Hakusui Bay, there was apparently little or no threat of foreign invasion, which is thought to be the reason for the lack of fortifications prior to this time. Even before the ill-fated Korean invasion, the Korean presence in Japan was important. The Soga clan, for example, that dominated the imperial household in the early part of the 7th century, is known to have been of Korean origin, and after the defeat of Kudara (Paekche / Baekje) its royal family and much of the nobility took refuge in Japan. The Koreans, who had long since been Japan's mentors in continental culture, are thought by most scholars to have shared at this time their fortification technology. These 6 castles listed in the ancient chronicles, along with a few others constructed in the following century, are called Chōsen Shiki Yamajiro, 朝鮮式山城, "Korean Style Mountain Castles". (The Wikipedia articles linked to are the best discussion of them I've been able to locate.)
Civil War - The Jinshin no Ran
The Emperor Tenji, who had named his brother as his heir, abruptly changed his decision in favor of a favorite son. The disinherited brother retired from the Åtsu capital, and the son soon succeeded his father on the throne. Tenji's choice was not universally approved by many of the clans, which still exercised considerable power, and the brother was able to raise an army from his base in Yoshino, a temple and shrine complex in the mountains south of the Nara Basin. In mostly July of 672, the brother led his army in a war of rebellion, with battles fought in modern Osaka, Nara, Mie, and Shiga Prefectures. After his victory, the brother burned the Åtsu capital, and, ascending the throne as the Emperor Tenmu, established his seat in the Asuka area in the south-east corner of the Nara Basin. Soldiers quartered at Takayasu Castle are recorded to have witnessed some of the conflicts. The chronicles record imperial visits to the castle by Tenmu, JitÅ, Monmu and Genmei. They also establish that the castle was abandoned in 701.
Discovery of the Takayasu Castle Remains
Although the existence of a 7th century castle on Mount Takayasu was a well-established historical fact, nothing was known about its actual location until late in the 20th century. In 1978 a citizens group from the City of Yao at the mountains western base made it their purpose to search for the castle's location and were able to locate the remains of 6 buildings in the area marked "S" of the overlay map. They conjectured that these buildings had been a supply depot for the Takayasu garrison. The site was named after a nearby place name, in Japanese "Kana ya zuka Soseki SÅko Gun" or in English something like "Metal and Mound Foundation Stone Warehouse Group".
The site marked "S" on the map was studied by a team from the Kashihara Archeological Research Institution in 1982. In their excavation, they found a number of ceramic objects under the foundation stones which had been used to support pillars. Some of these objects were dated from the Nara Period, that is, after the 701 date when Takayasu Castle is known to have been abandoned. It did not conclusively prove that this group of buildings was not part of the illusory castle, but it greatly weakened the conjecture that they were.
Mr. Yoneda's narrative begins: On March 18th of 1999, a colleague and I were investigating the lower of two large 6th century kofun built high on the slope of Mt. Takayasu. We casually looked up and saw a line on stones extending horizontally across the ridge above us. These building stones, over a meter on a side, were lined up with their flat surfaces facing outward. At first we thought that the stones had been arranged to provide a flat surface in front of the second kofun behind it. But when we followed the line of arranged stones, we found that it continued around the ridge line as it dipped into the canyon to the northeast. What, we wondered, was the significance of this line of stones. Could it, we wondered, be a trace of the Takayasu castle written about in the ancient chronicle?
Remains of an outer fence line of Takayasu Castle
This line of stones was found at an elevation of about 390 meters, as far as we could determine using a topographical map. We marked other ridge lines as they descended from the mountain at similar elevations, and determined we would explore these areas, the only way possible, on foot, which we did. The places where we found recognizable human-created changes in the topography like similarly shaped stone arrangements or flatten areas are labeled points A through F on the Osaka (Kawachi) side of the mountain, and point G on the Nara (Yamato) side.
The Document Record and The Outer Fence Line
In the literature up to this point, researchers have postulated that the outer boundaries of Takayasu Castle were located away from the mountain top on the Nara Prefecture (Yamato) side of the mountain, but we found problems with that supposition in the historical records. The first problem arises from a passage in the Nihon Shoki, the second historical chronicle compiled in 720 AD. There is an account in that book which says of the army of Sakamoto Omi Takara stationed at Takayasu Castle at the time of the Jinshin no Ran (the brief civil war mentioned above) which says, âWhen he looked down to the west early one morning, he saw armies coming both ways from Åtsu and Tajihi, and there were many soldiers. Their flags could be clearly seen." But neither the route from Åtsu nor the route from Tajihi can be seen from the top of the Takayasu ridgeline. To see either, one must stand on one of the ridges that extend westward from the mountain top.
Our second objection to the supposition that Takayasu castle was located entirely on the Nara (Yamato) slope of the mountain comes from a passage in the Shoku Nihongi, a chronicle compiled near the end of the 8th century. It says, "On August 26, 701, Takayasu Castle was demolished and the buildings and various stockpiles of supplies were moved to the two districts of Kawachi and Yamato."
It makes little sense, if the castle boundaries were entirely on the eastern slope of the mountain, as previous researchers have concluded, that some of the dismantled buildings and military supplies would have been carried up over the top of the mountain and down the Kawachi side. Such a course of action would make much more sense if the boundaries of the castle were those suggested by our findings: a rectangle like shape, approximately 1 kilometer east and west and 2 kilometers north and south, and including the crest of the Takayasu ridgeline within.
Because of these discoveries the above mentioned problems are resolved, and if the Point S buildings (the Kana ya Zuka Soseki SÅko Gun) are not from the Takayasu Castle era, it may be said that there is a strong possibility that they existed within the boundaries of the former castle.
Mr. Yoneda, who was trained as an archeologist, now does administrative work. In his spare time he (along with Mr. Okuda) is still pursuing his search for Takayasu Castle remains.
築城の背景
韓国の西にあった百済と呼ばれた国がの唐(中国)と韓国の東にあったもう一つ国である新羅の連合軍にAD660年に滅ぼされました。 天智2(AD663)年、大和朝廷が朝鮮半島に送った倭(日本)軍と百済復興軍が韓国にある白村江で、唐、新羅連合軍と戦い敗れました。それによって、大和朝廷は倭国防衛のために西日本各地に山城が築きました。 天智5(AD666)年には山口県に長門城、福岡県に大野城と佐賀県に基肄城、天智6(AD667)年には大阪府に高安城、香川県に屋島城、長崎県対馬に金田城が築城されています。 高安城では、皇位継承をめぐる内乱である壬申の乱(672年)の時に吉野軍と近江軍との間で攻防戦が行われました。 その後天武、持統、文武、元明といった歴代の天皇がここを訪れています。しかし大宝元(701)年に廃城となりました。
高安城の遺構の発見
高安城については長い間幻の城とされ、所在が不明でしたが昭和53(1978)年に八尾市の市民グループであった「高安城を探る会」によって6基の倉庫跡の礎石が発見されました。そこは金ヤ塚礎石倉庫群と呼ばれ、1982年に橿原考古学研究所によって発掘調査が行われ、その結果この建物の礎石の下より高安城の廃城後である奈良時代の土器が出土したことから、この倉庫群も高安城の遺構ではない可能性が強くなりました。 高安城は再び幻の城となってしまいました。
1999年3月18日に二人の研究者が高安山中腹に所在する古墳の調査をしていた時、巨大な横穴式石室を持つ古墳から何気なく山の上方を見上げると標高390m付近に大きな石が列をなして並んでいるのが見えました。石材は長径1m以上で、平坦な面を外側に向けられ、据えられています。当初この列石は上の古墳の墳丘の施設ではないかと思われました。
そこで列石をたどって行くとそれは古墳とは関係なく、尾根の東北側の谷へ向かって真直ぐ続いていることを確認しました。列石は面を外側に揃え、加工したような石材も使用されていました。
高安山中の巨大な列石は何を意味するのでしょうか?彼らはそれこそ日本書紀に記載された高安城の遺構ではないかと考えました。
そこで高安山の地形図を広げ、同じ標高380m~390m付近の等高線を注意深く見てみました。そうするといくつかの地点で人工的な地形を見つけだすことができました。
高安城の外郭線の遺構
彼らはそれらの地点に西側の北から順にアルファベットでA地点からF地点、さらに金ヤ塚倉庫群を挟んだ反対側である東側に所在する遺構をG地点と呼び、そして踏査することにしました。地形図に従って探査を行い人工的な地形を調べました。するとのその結果A~G地点で石垣や列石の存在や上面がフラットな台形状の地形を発見することができました。
文献記録と外郭線
従来の研究者は高安城の外郭線を山頂より奈良県側に想定していました。しかし、文献の記録からはいくつかの点で疑問がありました。まず第1点は日本書紀です。 その記事によると壬申の乱の時に高安城に進駐した坂本臣財の軍が「会明に、西の方を臨み見れば、大津・丹比、両の道より、軍衆多に至る。顕に旗旘見ゆ。」と記載されていますが高安山の山頂からは大津道も丹比道も見えません。そこを見ようとすれば高安山の西側に張り出した尾根の上に立つ必要があります。 第2点は続日本紀です。 続日本紀によると「大宝元年八月二十六日、高安城を廃止し、その建物や種々の貯蔵物を大和・河内の二国に移した。」 とあります。高安城の外郭線が奈良県側にあったとする従来の説では、河内(大阪府)に建物を移す必要はありません。 彼らが確認した地点から推定する高安城の範囲は大阪府(河内)と奈良県(大和)の境を跨ぐ東西1km、南北2Kmのほぼ長方形の範囲です。この発見によって上記の疑問が解決することと金ヤ塚礎石建物が高安城の時代のものでないとすれば、現在のところこの外郭線が高安城のものである可能性が最も高い遺構群であるといえます
参考文献
1983『夢ふくらむ幻の高安城』 第1集・第2集 高安城を探る会
1985 棚橋利光著『古代高安城論』 高安城を探る会
1998『高安城と古代山城』八尾市立歴史民俗資料館
1999「高安城の外郭線について」『古代学研究』第148号 古代学研究会
1999「築倭国高安城の発見」『大阪春秋』第90号 大阪春秋社
2000『高安城の外郭線 -探索一年を終えて―』奥田尚他
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