119.Sugiyama Castle Part1

A castle which has both an advanced defense system and a mysterious history

Location and History

Simple but Popular Castle

Sugiyama Castle was located in Hiki District, what is now in the western part of Saitama Prefecture. The ruins of the castle recently became popular among history fans in Japan. The ruins are not so large and have no buildings and no stone walls. The ruins are all made of soil. In addition, it is also uncertain when and who built and used the castle. There are no clear records about the castle at all. So, what did the castle become famous for? The answer is that the castle had a surprisingly artful defense system for such a small local castle.

MarkerMarker
Sugiyama Castle
Leaflet, © OpenStreetMap contributors
The location of the castle

“Sugiyama Castle Problem”

Historians have tried for a long time to find out when and who built Sugiyama Castle. However, their conclusions became more complicated. When the excavation team researched the castle ruins, they thought the castle was built and used around early 16th Century based on the unearthed relics. The Uesugi Clan, which governed the Kanto Region, had internal conflicts in the area around the castle at that time. The team speculates the clan built the castle. On the other hand, the researchers who study the layout of castles argue that the complex defense systems like Sugiyama Castle should have appeared later, such as in the late 16th Century. They think the Hojo Clan, which governed the Kanto Region after the Uesugi Clan, must have built such an advanced defense system. People call this discussion “Sugiyama Castle Problem”. The problem might even make the castle more popular.

The family crest of the Uesugi Clan called the Uesugi Bamboo Grass (licensed by Mukai via Wikimedia Commons)
The portrait of Ujityasu Hojo, the lord of the clan in the 16th Century, owned by Odawara Castle (licensed under Public Domain via Wikimedia Commons)

“Textbook for Building Castles”

Sugiyama Castle was built on a hill. The hill measured 42m high from the base. The castle had 10 enclosures, including one in the center of the castle. The enclosures spread into three directions in the south, north and east. These enclosures were built to protect the center of the castle called the Main Enclosure. The west of the castle was a steep cliff with a river flowing below, which was a natural hazard. All the enclosures were surrounded by earthen walls and dry moats and connected by earthen or wooden bridges. The most important feature of its defense system was that all the entrances of the enclosures were protected by the frank attacks or Yokoya. Protection was provided by the clever layout of the L-shaped earthen walls and the route to the enclosures. The design of the castle was highly sophisticated, so it is now often called “a textbook for building castles”.

The miniature model of the castle ruins, exhibited in the Ranzan Town Office

Castle may be Temporary

The excavation found that Sugiyama Castle didn’t have permanent buildings such as halls, turrets, and gates. It probably only had temporary buildings like huts and fences. It was also found that the castle was used for a short time because it was not modified before it was destroyed by fire. This means that the castle could have been built for a single purpose or battle. There were many other castles around Sugiyama Castle, which were also built probably for a single purpose. Many of these castles, such as Ogura Castle, had distinct features. Many battles happened around this area in the 16th Century during the Sengoku Period. It is thought that the warlords in this area built residential castles as well as single-use castles to survive. Even though Sugiyama Castle may have been one of the latter, it had a surprisingly technical defense system.

The whole view of Sugiyama Castle Ruins, from the signboard at the Ranzan Town Office
The ruins of Ogura Castle, this castle has stone walls which were rare in the Kanto Region when it was built

To be continued in “Sugiyama Castle Part2”

119.杉山城 その1

先進的防御システムをもった謎の城

立地と歴史

地味なのに有名な城

杉山城は、現在の埼玉県西部にあたる比企郡に築かれた城でした。この城の城跡は、日本の歴史ファンの間で最近有名になっています。この城跡は、それほど大きくもなければ、建物も石垣もありません。基礎は全て土造りです。更には、いつ誰がこの城を築き使ったのかもわかっていません。この城に関する明確な記録がないのです。それでは、なぜこの城は有名になったのでしょうか。それは、この城が地方の小さな城としては、驚くほど巧みな防御システムを持っていたからなのです。

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杉山城
Leaflet, © OpenStreetMap contributors
城の位置

「杉山城問題」

歴史家は長い間、杉山城がいつ誰によって築かれたのか解明しようとしてきました。ところが、その結論は、ますます複雑化してしまっています。城跡で発掘調査が行われたのですが、発掘された遺物から多くの研究者は、この城は16世紀初頭に築かれ、そして使われたと考えました。その当時この城の周辺地域では、関東地方を支配していた上杉氏が内紛を起こしていました(山内上杉氏と扇谷上杉氏との間で起こった長享の乱など)。上杉氏がこの城を築いたとしたのです。一方、縄張り研究者たちは、杉山城に見られる複雑な防御システムは、16世紀後半くらいの、もっと後の時代に見られるものだと反論しました。こちらは、上杉氏の後に関東地方を支配した北条氏が、このような先進的な防御システムを築いたに違いないとしたのです。この議論は「杉山城問題」と言われています。この問題が、この城をより一層有名にしたのかもしれません。

上杉家の家紋、上杉笹 (licensed by Mukai via Wikimedia Commons)
16世紀後半の北条氏当主、北条氏康肖像画、小田原城所蔵  (licensed under Public Domain via Wikimedia Commons)

「築城の教科書」

杉山城は、麓からの高さ42mの丘陵の上に築かれました。城には中心部のものを含め、10個の曲輪がありました。それらの曲輪は、南北と東の三方向に広がっていて、城の中心部の本郭を守るように作られていました。城の西側は急な崖となっていて、崖下に流れる川とともに天然の障壁となっていました。全ての曲輪は、土塁そして空堀に囲まれていて、土橋か木橋によって接続されていました。この城の防御システムの最も重要な特徴は、全ての曲輪の入口が横矢(側面攻撃)によって守られていることでしょう。この仕組みは、巧みな土塁の屈曲と曲輪への導線によって成り立っていました。この城の設計は高いレベルで洗練されていて、現在では度々「築城の教科書」とも呼ばれています。

杉山城跡の模型(嵐山町役場にて展示)

一時的な目的で築城か

発掘の結果によると、杉山城には、館、櫓、門といった常設の建物はありませんでした。恐らく、小屋や柵といった仮設の建物だけがあったと思われます。また、この城は短期間しか使われなかったことがわかっています。火をかけられて破壊されるまで、一度も改修されていないからです。これは、この城が単一の目的か戦いのために作られたからと考えられます。杉山城の周辺には、他にも多くの単一目的で作られたであろう城が存在しました。これらの城には、例えば小倉城のように、それぞれ明確な特徴があるのです。戦国時代の16世紀には、この地域には多くの戦いが起こりました。この地域の戦国大名は、自分たちが住むための城だけでなく、戦いに勝ち抜くために使い捨ての城も築きました。たとえ杉山城が後者のうちの一つであったとしても、驚くほど技巧的な防御システムを持った城であることには変わらないのです。

杉山城跡全景(嵐山町役場説明板より)
小倉城跡、その当時の関東地方の城としては珍しく石垣が築かれています

「杉山城その2」に続きます。

125.Kozukue Castle Part1

The castle in the center of the popular Kozukue Territory

Location and History

Castle along one of Kamakura Roads

Kozukue Castle was located in what is now the northern hilly area in Yokohama City, Kanagawa Prefecture. In the present Japan, Tokyo is the center of Japan including the Kanto Region. For that reason, many major roads gather in or spread from Tokyo. Some of them also go through the eastern seaside area of Yokohama City. However, before the Edo Period which started in the 17th Century, the center of the Kanto Region was Kamakura, called the Warriors’ Capital. Many major roads, called the Kamakura Roads, at that time also gathered in or spread from Kamakura. Kozukue Castle was near one of the Kamakura Roads and alongside Tsurumi-gawa River, which was an important spot for transportation.

MarkerMarkerMarkerMarker
Kozukue Castle
Leaflet, © OpenStreetMap contributors
The location of the castle

The present road network of the Kanto Region going to and from Tokyo (Source: Ministry of Land, Infrastructure and Transport)
The past road network of the Kanto Region going to and from Kamakura (Source: Tama City, adding the positions of Kozukue Castle and Kamakura)

“Kozukue Territory” and “Kozukue Group”

It is uncertain when Kozukue Castle was first built. The first appearance of the castle was after the Rebellion of Kageharu Nagao, who was against his master, the Uesugi Clan in 1478. The Toshima Clan who supported Kageharu used the castle, and Dokan Ota, a senior vassal of the Uesugi Clan beat them. After a while, the Hojo Clan, a great warlord used the castle again as a bridgehead for invading the Kanto Region in the 16th Century during the Sengoku Period. Even after the Hojo Clan was succeeded, they still considered the area around the castle as one of their important territories. They called the area “Kozukue Territory” like we call the area today, Yokohama City. They also called the group of the warriors who lived in the area “Kozukue Group”. Kozukue Castle was the center of the area and the group, and one of Hojo’s branch castles, which must have been more popular than we assume.

The portrait of Dokan Ota, owned by Daijiji Temple (licensed under Public Domain via Wikimedia Commons)
The portrait of Ujitsuna Hojo, the lord of the clan when they invaded the Kanto Region, owned by Odawara Castle (licensed under Public Domain via Wikimedia Commons)

Castle has Simple Layout

Kozukue Castle was built on the edge of a hill sticking out from the south towards Tsurumi-gawa River to the north. The layout of the castle was simple, having the large Western and Eastern Enclosures, divided by the slender Connecting Enclosure. They were all made of soil. However, these enclosures were surrounded by large deep dry moats. What kinds of buildings stood on the enclosures is still uncertain, but it is thought that some turrets were built on the earthen bases. In addition, some barbicans were built along the hill around the main portion.

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Kozukue Castle
Leaflet|国土地理院
The relief map around the castle

The imaginary drawing of Kozukue Castle (from the signboard at the site, adding comments)

Development and Abolition of Castle

In 1590, when the ruler, Hideyoshi Toyotomi invaded Hojo’s territory for his unification of Japan, Hojo ordered their branch castles to gather the warriors to their home base, Odawara Castle. That meant the branch castles including Kozukue Castle had to protect themselves with fewer defenders. The lord of Kozukue Castle decided to draft farmers to protect it. It is thought that the dry moats of the castle were also developed making them larger and deeper to protect the castle with fewer warriors and untrained defenders. This is what we can now see as the ruins of the castle. However, no battles happened then. The castle was open and finally abandoned after Hojo surrendered to Hideyoshi.

The Portrait of Hideyoshi Toyotomi, attributed to Mitsunobu Kano, owned by Kodaiji Temple (licensed under Public Domain via Wikimedia Commons)
The dry moat of Kozukue Castle

To be continued in “Kozukue Castle Part2”

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