The castle for the western defense of the Hojo Clan
Location and History
Western Defense for Hojo Clan
Yamanaka Castle was located on the west of Hakone Barrier, the western gateway of Kanto Region, now in the eastern part of Shizuoka Prefecture. The castle was first built in the middle 16th Century during the Sengoku Period by the Hojo Clan, who owned Kanto Region. The clan aimed to protect their home base, Odawara Castle on the eastern side of Hakone Barrier, by building Yamanaka Castle. This castle was also improved before the ruler, Hideyoshi Toyotomi, attacked the Hojo Clan in 1590.
The location of the castle
Yamanaka Castle was built surrounding the Tokaido Road, one of the major roads in Japan. During that time, if someone walked up the slope on the road from the west, it would require passing through the castle. The road was actually on the Third Enclosures of the castle, and beside the Main Enclosure. The Third Enclosure also had water moats on the west to prevent enemies’ attacks and was for the water reservoir. On the south of the Third Enclosure, a long defense strongpoint called “Taizaki-demaru” spread with the road parallelly. On the west of the Third Enclosure, the Second Enclosure, the West Enclosure, and the West Turret were added towards that direction. These enclosures were able to work closely to prevent attacks from enemy forces.
The location map of the ruins of Yamanaka Castle (from the signboard at the site)
Hojo’s Unique Methods for building Castle
The techniques used in the castle were unique to the Hojo Clan. All the enclosures were made of earthworks, using natural terrain such as ridges and valleys. They were mainly connected by wooden bridges which could fall down when a battle happened. They were also divided by deep dry moats whose bottoms were left parallel or as latticed ridges. The method for building the moats is called “Une-bori” for the parallel ridges and “Shoji-bori” for the latticed ridges. These dry moat building methods are considered features of the Hojo’s castles. Once soldiers fell into the moat, they couldn’t move from there at all. The area of the castle reached about 200,000 square meters. Hojo thought the castle could make Hideyoshi stuck for a while.
“Une-bori” for the parallel ridges“Shoji-bori” for the latticed ridges
Fall in Battle of Yamanaka Castle
However, the castle was captured by Hideyoshi in just half a day. In the early morning, March 29, 1590, nearly 70,000 soldiers of Hideyoshi’s troop started to attack the castle, while the number of the defenders was only about 4,000. The attackers first charged both the West Turret and the Taizaki-Demaru defense strongpoint, but they suffered a significant number of casualties by the counterattack of Hojo’s guns. If it was a local battle, the attacker might have paused the charge to prevent more damages. However, the commanders forcibly continued to charge, otherwise, they might have been fired by the ruler. That resulted in the success of capturing the castle for Hideyoshi in exchange for a lot of dead soldiers including one of the Hideyoshi’s commander, Naosue Hitotsuyanagi.
The Portrait of Hideyoshi Toyotomi, attributed to Mitsunobu Kano, ownd by Kodaiji Temple (licensed under Public Domain via Wikimedia Commons)
This battle lasted for a few hours. It is said that another reason for the short battle was that Hojo’s soldiers were confused because their head, Ujikatsu Hojo, escaped from the castle. Others point out that the Taizaki-Demaru defense strongpoint was unfinished in construction before Hideyoshi’s attack. Anyway, even such a strong castle couldn’t survive without enough soldiers and the right instructions.
名胡桃事件で有名な城
The castle famous for the Nagurumi Incident
立地と歴史～Location and History
沼田城への橋頭保～Foothold for Numata Castle
名胡桃城は上野国（現在の群馬県）北部にありました。この城は戦国時代の１６世紀後半に大河である利根川西岸の崖の上に築かれました。川を渡った反対側には沼田城があり、そこは関東地方の戦国大名にとっては非常に戦略的な拠点でした。武田氏の配下であった真田氏が沼田城を確保するための橋頭保として1579年に名胡桃城を築き、1580年には実際に沼田城を手に入れました。 Nagurumi Castle was located in the north part of Kozuke Province (what is now Gunma Prefecture). It was built in the late 16th Century during the Sengoku Period, on a cliff near the west bank of a large river called Tone-gawa. At the opposite side across the river, there was Numata Castle which was a very strategic spot for warlords in Kanto Region. The Sanada Clan under the Takeda Clan built Nagurumi Castle in 1579 as a foothold for capturing Numata Castle which actually belonged to Sanada in 1580.
城の位置～The location of the castle
城周辺の起伏地図～The relief map around the castle
名胡桃事件の発生～Nagurumi Incident happens
真田氏はしばらく沼田城を維持していましたが、1589年7月の天下人豊臣秀吉の裁定により、北条氏に引き渡されてしまいます。一方真田氏は、名胡桃城はまだ領土の一部としていました。この裁定は北条が秀吉の臣下になるという条件の下に行われました。1589年11月、豊臣秀吉の命令に逆らい、北条は名胡桃城を占領しました。この事件は名胡桃事件と呼ばれています。真田氏は秀吉に事件のことを訴え、秀吉は激怒し北条を成敗することを決定しました。北条氏は当時最も有力な戦国大名の一つでしたが、この事件は1590年の小田原征伐での滅亡につながります。定説によれば、北条は世の中の流れを見誤ったとされています。 The Sanada Clan held Numata Castle for a while, but the castle was handed over to the Hojo Clan under the decision by the ruler Hideyoshi Toyotomi in July 1589, while Sanada still kept Nagurumi Castle in their territory. The decision was made on condition that Hojo would become a vassal of Hideyoshi. In November 1589, against the instructions of Hideyoshi Toyotomi, the Hojo Clan seized Nagurumi Castle. The incident at the castle is called the Nagurumi Incident. The Sanada Clan appealed it to Hideyoshi who was very angry about it and decided to defeat Hojo instead. The Hojo Clan was one of the greatest warlords at that time, but this incident led to their fall in the Siege of Odawara Castle in 1590. The established theory says Hojo misjudged the current tide.
豊臣秀吉肖像画、加納光信筆、高台寺蔵～The Portrait of Hideyoshi Toyotomi, attributed to Mitsunobu Kano, ownd by Kodaiji Temple（licensed under Public Domain via Wikimedia Commons）
秀吉と真田の陰謀か～Trick by Hideyoshi and Sanada?
しなしながら、歴史家の森田喜明は、この事件は秀吉と真田による謀略であったと反論しています。秀吉が残した手紙によると、彼は既に遅くとも1589年の10月には北条を成敗することを決めていたと言います。秀吉が1589年12月にこの事件のことを北条に問いただした時、北条は平然と、名胡桃城もまた真田から北条に引き渡されたものであり、秀吉に会うための準備を引き続き進めていると答えています。実は、秀吉が名胡桃城を真田側に留めるという裁定内容は、彼から北条への手紙に初めて出てくるのです。更には、発掘調査によれば、名胡桃城跡では戦いや火災があった跡は発見されていません。この新説は実に興味深いものです。 However, a historian Yoshiaki Morita argues that this incident was a trick made by Hideyoshi and Sanada. He says that Hideyoshi had already decided to defeat Hojo at latest in October 1589 according to Hideyoshi’s letters. When Hideyoshi asked Hojo about the incident in December 1589, Hojo answered Hideyoshi calmly that Nagurumi Castle had also been handed over to Hojo by Sanada and they still continued to prepare the meeting with Hideyoshi. In fact, the decision by Hideyoshi to keep Nagurumi Castle on Sanada’s side was shown in his letter to Hojo for the first time. In addition, there is no evidence of a battle or fire in the ruin of Nagurumi Castle according to the excavation team. This new theory is very intriguing.
北条氏政肖像画、当時の北条氏当主、小田原城天守閣蔵～The portrait of Ujimasa Hojo, the head of the Hojo clan at that time, owned by Odawara Castle (licensed under Public Domain via Wikimedia Commons)
いずれにしろ、北条氏が滅んだ後、沼田・名胡桃両城は真田氏のものとなりました。名胡桃城はその後すぐに廃城となります。真田による沼田城の支配が安定し、その役割が既に終わったからです。城の生涯は１０年あまりでした。 Anyway, the fact is that the Sanada Clan owned both Numata and Nagurumi Castles again after the Hojo Clan was defeated. Nagurumi Castle was abandoned soon after that because its role had already ended when Sanada’s governance of Numata Castle became stable. The castle survived for more than ten years.
城の想像図～The imaginary drawing of the castle (現地説明板より～from the signboard at the site)
特徴～Features
自然の地形を生かして築城～Built using Natural terrain
現在、名胡桃城跡は行政によりよく整備されていますが、規模は大きくありません。それは、沼田城を手に入れるための橋頭保という、この城の目的が特定且つ一時的なものだからです。しかしながら、この城が崖から突き出た岬のような自然の地形を生かして作られているのが今でもよくわかります。この地形は、空堀によって三つの主要な郭～主郭、二郭、三郭、に先から元に向かって分かれています。その先には更に２つの郭～ささ郭と物見郭が見張りのために加えられていました。 Now, the ruins of Nagurumi Castle are well developed by officials, but their scale is small. This is because the purpose of the castle, the foothold for capturing Numata Castle, was specific and temporally. However, you can even now see the castle is built using the natural terrain of a shape like a cape sticking out of the cliff. The terrain is divided by dry moats into the three major enclosures – the Main Enclosure, the Second Enclosure, and the Third Enclosure from the top to the bottom. Over the top, two more small enclosures – Sasa-Kuruwa and Monomi-Kuruwa were added to look out.
城周辺の航空写真～The aerial photo around the castle
根元の方には「馬出し」と呼ばれる丸い形で突き出ている防御システムが加えられ、現在でもその形をなぞった線によりわかるようになっています。 At the bottom, a sticking out round shaped defensive position called “Umadashi” was added, the tracing line for the Umadashi shows it now.
馬出しの跡を示す線～The tracing line for the Umadashi system馬出しの想像図～The imaginary drawing of the Umadashi system (現地説明板より～from the signboard at the site)馬出しと三郭～The Umadashi system and the Third Enclosure
主要部分の構造～Structures of Main Portion
これらの郭の間をつなぐ木橋と接続部分が復元されています。それぞれの郭は簡単な櫓とともに高い土塁と今よりずっと深い空堀によって囲まれていました。二郭は大きな郭でいくつかの建物がありました。主郭には城の記念碑が設置されています。ささ郭まで行くことができ、利根川と沼田市域の景色を眺めることができます。 Wooden bridges and zigzagged connecting points have been restored between these enclosures. Each enclosure was surrounded by high earthen walls with simple turrets and much deeper dry moats in the past. The Second Enclosure is the large one where several buildings stood. The monument of the castle is placed on the First Enclosure. You can go as far as the Sasa-Kuruwa Enclosure to have a view of Tone-gawa River and Numata City area.
三郭と二郭の接続部分～The connecting point between the Third Enclosure and the Second Enclosure三郭と二郭の間の空堀～The dry moat between the Third Enclosure and the Second Enclosure接続部分の想像図～The imaginary drawing of the connecting point (現地説明板より～from the signboard at the site)二郭～The Second Enclosure二郭の想像図～The imaginary drawing of the Second Enclosure (現地説明板より～from the signboard at the site)二郭と主郭の接続部分～The connecting point between the Second Enclosure and the Main Enclosure主郭～The Main Enclosureささ郭へ～Going to the Sasa-Kuruwa Enclosureささ郭の想像図～The imaginary drawing of the Sasa-Kuruwa Enclosure (現地説明板より～from the signboard at the site)ささ郭～The Sasa-Kuruwa Enclosureささ郭からの眺め～A view from the Sasa-Kuruwa Enclosure
その他の見所～Other Attractions
城で最も大きな郭は般若郭で、他の郭とは別の並びの所にあります。この郭は、多くの兵士を駐屯されるために使われたと考えられています。現在は、ここに車を駐車できます。 The largest enclosure in the castle called Hannya-Kuruwa is in a different line from the other enclosures. It is thought that this enclosure was used to station a lot of soldiers. You can now park your car at this enclosure.
般若郭～The Hannya Enclosure
城址案内所では城とその歴史のついてより学ぶことができます。もちろん、そこで説明されているのは、この城は決して北条に引き渡されていなかったという定説の方です。 You can learn more about the castle and its history at the information office. Of course, the explanation of the office is based on the established theory that the castle of never handed over to Hojo.
城址案内所～The information office
その後～Later History
名胡桃城は早くに廃城となりましたが、その名はとてもよく知られています。例えば、江戸時代後期の有名な日本の歴史書である「日本外史」には名胡桃事件のことが書かれています。1923年、地元の人々が城の保存会を立ち上げ、1927年には本郭に記念碑を建て、歴史公園として城跡を整備しました。更に最近では、みなかみ町が1992年から2006年までの間、城の発掘を行いました。2015年までに町は、詳細な発掘の成果に基づき土塁や木橋の一部の復元を行い、公園の整備を進めました。城跡は現在、群馬県の史跡に指定されています。 Nagurumi Castle was abandoned earlier, but its name is very well known. For example, a famous textbook for Japanese history in the late Edo Period, called “Nihon-Gaishi”, described the Nagurumi Incident. In 1923, the local people launched the preservation society for the castle and developed the ruins as a historical park building the monument at the Main Enclosure in 1927. In more recent years, Minakami Town excavated the castle between 1992 and 2006. By 2015, the town had developed the park more by restoring part of the earthen walls and wooden bridges according to the details of the achievements of the excavation. The ruins is now designated as a Prefectural Historic Site of Gunma.
本郭にある記念碑～The monument at the Main Enclosure
私の感想～My Impression
名胡桃城は広くもなく、石垣の上の天守のような大きな建物もありませんでした。しかし、戦国大名が築いた無数の城の一例なのです。ほとんどの城は特定の目的のみに作られ、その役目を終えれば廃城となりました。名胡桃城はそのような城だったのですが、有名になったがゆえによく整備された城跡として見ることができるのです。この城は地味ですが有益だと思います。そして実際の歴史を学ぶためによい教材だと思うのです。 Nagurumi Castle was not large and didn’t have large buildings like a Main Tower on stone walls. However, it was an example of an uncountable number of castles warlord built. Most of these castles were built just for their specific roles and abandoned after their roles ended. Nagurumi Castle was one such castle, but we can enjoy seeing its well-developed ruins because the castle has become famous. I think the castle is simple, but useful. It is a good teaching resource for people to learn real history.
城跡の入口～The entrance of the castle ruin
ここに行くには～How to get There
関越自動車道の月夜野ICから約１０分のところにあります。般若郭に駐車場があります。 公共交通機関を使う場合には、上越新幹線の上毛高原駅か、ＪＲ上越線の後閑駅からタクシーに乗ってください。 It takes about 10 minutes driving from Tsukiyouno IC on Kanetsu Expressway. The ruins offer a parking lot in Hannya-Kuruwa enclosure. If you want to go there by public transportation, take a taxi from Jomo-Kogen Station on Joetsu-Shinkansen Super express or from Gokan Station on JR Joetsu Line.
城跡は自然とともに残っています。
The castle ruins remain with nature.
本丸と中の丸をつなぐ曳橋～The movable bridge between Honmaru and Nakanomaru
立地と歴史～Location and History
滝山城は現在の八王子市の多摩川南岸の河岸段丘上にありました。この城の起源は、戦国時代のいずれかの時点で大石氏によると言われていますが、１５６０年の上杉謙信の関東侵攻をきっかけとして、北条氏照が拡張、完成させました。この城の使命は、小田原城の防御線になることと、小田原と北関東とのルートを確保することでした。 Takiyama Castle was located on the southern bank terrace of Tamagawa River in what is now Hachioji City, Tokyo. The origin of the castle is said to be by the Oishi clan sometime in “Sengoku” or the Warring States Period, but Ujiteru Hojo improved and completed the castle, inspired by the Kenshin Uesugi’s Kanto invasion in 1560. The mission of the castle was to be the defense line for Odawara Castle and to hold the route between Odawara and the northern Kanto region.
滝山城の位置、赤い線は1560年の上杉謙信の侵攻概略ルート、青い線は1569年の武田信玄のもの～The location of Takiyama Castle, the red line shows the rough attack route of Kenshin Uesugi in 1560, the blue line is that of Shingen Takeda in 1569
この城の北側は多摩川に沿って急な崖となっていて、攻めるには困難でした。この城の３つの主な通路は、川の反対側にある滝山街道につながっていました。これらの通路は全て二の丸に集まっていました。二の丸は防衛の中心拠点であり、桝形という方形の入り口と、馬出と呼ばれる障壁となる関門が通路に向かって設置されていました。 The northern side of the castle was a steep cliff along Tamagawa River which is difficult to attack. The three main routes to the castle were connected from the Takiyama Road, the opposite side of the river. The routes all gathered the Ninomaru enclosure. The enclosure was the defensive center which had square entrances called Masugata and gateway barriers called Umadashi heading towards these routes.
城周辺の起伏地図～The relief map around the castle
二の丸の後ろには、中の丸と本丸がありました。双方が曳橋という可動橋によってつながっており、緊急時には容易に取り外しが可能でした。本丸は、中心でかつ最後の曲輪となりますが、比較的小さいように思えます。歴史家は、そこが土豪が作ったこの城の最初の場所だったのだろうと推測しています。 The back of Ninomaru are Nakanomaru and Honmaru enclosures. Both were tied by a movable bridge called Hikihashi that could be removed easily for in emergency. Honmaru was the main and last enclosure which looked relatively small. Some historians speculate it could be the origin of the castle for a local clan.
城周辺の地図～The map around the castle
１５６９年、甲斐（現在の山梨県）から武田信玄が北条の領地に侵入し、この城を攻撃しました。信玄は二の丸に迫りましたが、諦めて小田原の方に向かったと言われています。氏照は滝山城を守り切ったのです。 In 1569, Shingen Takeda from Kai Province (now Yamanashi Pref.) invaded Hojo’s territory and attacked the castle. It is said that Shingen approached Ninomaru, but gave up and transferred to Odawara. Ujiteru was successful in keeping Takiyama Castle.
武田信玄肖像画、高野山持明院蔵、１６世紀～The portrait of Shingen Takeda, owned by Jimyo-in, in the 16th century（licensed under Public Domain via Wikimedia Commons）
１５８４年前後、氏照は城下町ごと八王子城の方に移っていきました。この理由は歴史家によって分かれています。一つは、武田との戦いの結果から北条がより強い城を必要としたというものです。もう一つは、１５７８年に謙信が死に、１５８２年に武田が滅亡したので滝山城はもう必要なくなったというものです。 Around 1584, Ujiteru moved to Hachioji Castle with the castle town. Historians’ opinion about the reason remain divided. One is that Hojo needed a stronger castle than Takiyama because of the result of battle with Takeda. The other is that there would be no need for Takiyama Castle after Kenshin died in 1578, and Takeda was destructed in 1582.
二の丸周辺～Around Ninomaru
特徴～Features
城周辺の航空写真～The aerial photo of around the castle
現在、城跡は都立滝山公園という自然公園の一部になっています。木々、植物、そして花に囲まれたハイキングコースがあります。車かバスを使った場合には、三の丸と小宮曲輪に挟まれた通路から入っていきます。 Now, the ruins of the castle are inside of a nature park called Metropolitan Takiyama Park. There are hiking trails among trees, plants and flowers. When using cars or buses, you will enter one of the routes sandwiched Sannnomaru and Komiya enclosures.
駐車場かバス停からの通路～The route from the parking lot or the bus stop
このルートは狭く、美しい竹林の合間をまっすぐ登っていきます。 The route is narrow and straight up among a beautiful bamboo forest.
竹林に囲まれた通路～The route surrounded by the bamboo forest
城跡の入り口は折れ曲がっていて、かつては城全体を囲んでいた長い空堀が目に入ってきます。 The entrance of ruins is zigzagged and you can see a long dry moat that surrounded the whole castle area in the past.
城跡の入り口～The entrance of the castle ruins城跡を囲む空堀～The dry moat surrounding the castle ruins
敵は、周りの曲輪による両側からの反撃を受けることになります。１５６９年の武田の攻撃によりこの辺りは占領されてしまったと言われています。 Enemies had to break counterattacks from both sides of the enclosures around. It is said that Takeda’s attack in 1569 was able to capture this area.
三の丸を見上げる～Looking up Sannomaru enclosure
道は左手に深い谷を見ながら進み、千畳敷と呼ばれる広場を過ぎ、防御の中心拠点二の丸に至ります。ここには馬出しと桝形の遺構があります。 The route goes on next to a deep valley on your left. Then, passing a wide area called Senjojiki, you will reach the defense center Ninomaru. There are the ruins of Umadashi and Masugata.
左手は深い谷です～The deep valley on the left千畳敷～The area called Senjojiki馬出し跡、正面～The ruins of Umadashi, the front side馬出し跡、背面～The ruins of Umadashi, the back side二の丸の中心地～The center of Ninomaru
その後、中の丸と本丸の間にかかった曳橋が見えてきます。 After that, you can see the restored movable bridge between Nakanomaru and Honmaru.
曳橋～The movable bridge中の丸から見た橋～The bridge from Nakanomaru
中の丸からは多摩川周辺の風景を眺めることができます。 You can also see a view of around Tamagawa River from Nakanomaru.
中の丸～Nakanomaru enclosure中の丸からの眺め～A view from Nakanomaru
最近の発掘により、本丸には桝形があり、その床には自然石が敷き詰めてあり、排水の仕組みもあったとのことです。 The recent excavation found that Honmaru had a Masugata gate on the floor covered with natural river stones, and a draining system.
本丸の桝形跡～The ruins of Honmaru Masugata gate本丸の内部～The inside of Honmaru
その後～Later History
この城は、戦国時代のうちに放棄されました。そのため、当時の城の構造がよい状態で自然とともに残っているのです。城跡は、１９５１年に国の史跡にも指定されました。 The castle was abandoned during the Warring States Period. That’s why the structure of a castle at that time remains well with nature. The ruins were designated as a National Historic Site in 1951 as well.
曳橋からの風景～A view from the movable bridge
私の感想～My Impression
城跡となっている場所は、主に自然公園として使われています。小道を歩き回っている観光客の人たちがたくさんいます。歴史ファンというよりは自然愛好家という感じです。これも史跡を活用する一つのやり方と思います。また、この城が自然の地形をうまく活用して作られたとも言えるでしょう。 The site of the castle ruins is mainly used as a natural park. You can see many tourists walking around the trails. They look like nature lovers rather than history fans. I think this is one of the ways to use historical sites. It also proves the castle was built using natural terrain very well.
小宮曲輪から通路を見下ろす～Looking down the route from Komiya enclosure
ここに行くには～How to get There
車で行く場合：中央自動車道の八王子ＩＣから約１５分かかります。国道411号（滝山街道）沿いに観光駐車場があります。 ＪＲ八王子駅または京王八王子駅からバスで行く場合：戸吹、秋川駅、または戸吹スポーツ公園入口行きバスに乗り、滝山城址下バス停で降りてください。 If you want to go there by car: It takes about 15 minutes from the Hachioji IC on Chuo Expressway. There is the parking lot for tourists along Route 411 (Takiyama Road). If you want to go there by bus from JR Hachioji station or Keio-Hachioji station: Take the bus for Tobuki, Akikawa-eki or Tobuki-sports-koen-iriguchi and take off at the Takiyama-joshi-shita bus stop.
