An important and strong castle in the northern Kanto Region
Location and History
Yoshisada Nitta comes from Nitta Manor
Kanayama Castle was located on Kanayama Mountain in modern day Ota City, Gunma Prefecture. The area around the city was called Nitta Manor in the Middle Ages, where the Nitta Clan, a relative of the Minamoto Clan which originated from the Imperial Family, settled in. It was on Tozando Route, a major one in Kanto Region, and was sandwiched between Tone River and Watarase River, two major ones in the region as well. In the past, large rivers could provide rich farmland, water transportation, and even barriers when a battle happened. That’s why the area of Nitta Manor was considered important.
The range of Ota City and the location of the castle
Iezumi Iwamatsu builds Castle
Yoshisada Nitta is the most famous person of the clan, who attacked and defeated the Kamakura Shogunate in 1333. However, he was unfortunately defeated in 1338 by troops of the Ashikaga Shogunate which Takauji Ashikaga who was also a descendant of the Minamoto Clan established. After that, the Iwamatsu Clan, a branch of the Nitta but supporting the shogunate, followed the manor. The lord of the clan originally lived in the hall on a plain area, called the Iwamatsu Hall. However, it got too dangerous to continue to do so, because many battles happened all over the Kanto Region since the Kyotoku War started back in 1454. Therefore, the lord of the clan at that time, Iezumi Iwamatsu decided to build his new home base on Kanayama Mountain in the northern part of the manor, which would eventually be completed in 1469, and be called Kanayama Castle.
The portrait of Yoshisada Nitta, owned by Fujishima Shrine (licensed under Public Domain via Wikimedia Commons)The ruins of Iwamatsu Hall which has become Shorenji TempleA view of Kanayama Mountain seen from around Iwamatsu Hall Ruins
Yura Clan overthrows Iwamatsu Clan
In the Sengoku Period when the Kanayama Castle was active, a popular trend called Gekokujo or Overthrowing their lords was often seen. In the case of the Iwamatsu Clan, their senior vassal, the Yokose Clan overthrew the Iwamatsu Clan, by supporting a puppet lord and killing an unmanageable lord. For example, the lord, Naozumi Iwamatsu was forced to retire and devote all of himself to the field of linked poem called Renga. The Yokose Clan finally changed their family name to the Yura Clan, declaring they were actually another branch of the Nitta Clan, which also meant a descendant of the Minamoto Clan. They needed not only real power but also the authority the people could respect, to survive as a local warlord during the period.
The self-portrait of Naozumi Iwamatsu, owned by Shorenji Temple, one of the earliest self-portraits in Japan (licensed under Public Domain via Wikimedia Commons)The tomb of Naozumi Iwamatsu, located near Shorenji Temple
Hojo Clan takes over and completes Castle
In the late 16th Century, much larger warlords than the Yura Clan, such as the Hojo, Uesugi, and Takeda Clans, battled each other over the Kanto Region. The policy of the Yura Clan was to deal and follow the strongest warlord each time as other local lords did. The lord of the clan, Narishige Yura even mediated between the Hojo Clan and Uesugi Clan in 1569 to provide Kanayama Castle for their negotiation, but unfortunately, the alliance lasted only a short time. The clan following one great warlord meant that they could be attacked by other great warlords. Kanayama Castle was actually attacked several times by all the three warlords, the Hojo, Uesugi, and the Takeda, however, never failed. That’s why this castle was considered impregnable and called one of the Seven Great Castles in the Kanto Region. The Kanto Region eventually belonged to the Hojo Clan, which forced the Yura Clan to hand Kanayama Castle over to the Hojo Clan in 1585.
The tomb of Narishige Yura (in the center) at Kinryuji Temple near the castle ruinsThe portrait of Ujiyasu Hojo whom Naozumi suggested the alliance with the Uesugi Clan, owned by Odawara Castle (licensed under Public Domain via Wikimedia Commons)The portrait of Kenshin Uesugi whom Naozumi suggested the alliance with the Hojo Clan, owned by Uesugi Shrine (licensed under Public Domain via Wikimedia Commons)
The first stage of Kanayama Castle seemed to be built on around the top of the mountain and made of soil. As time passed by, the castle was developed and improved greatly. It is said that the Hojo Clan completed the final version of the castle. They expanded the range of the castle from the top to the western and southern ridges of the mountain. They also improved the main portion of the castle by building stone walls and even stone paving. The castle didn’t have the Main Tower which major castles in western Japan often had, but it is very rare case for those in eastern Japan to have full-scale stone walls at that time.
The restored Main Entrance of Kanayama CastleThe miniature model of the Main Entrance of Kanayama Castle, exhibited by Historic Site Kanayama Castle Guidance Facility
Abrupt ending of Castle
The main history of Kanayama Castle ended all too soon in 1590 when the ruler, Hideyoshi Toyotomi invaded the Hojo’s territory in order to unify Japan. Kanayama Castle was governed by the Hojo’s retainers, but many of them were ordered to gather in Odawara Castle, the Hojo’s home base, so only a few defenders remained in Kanayama Castle. That’s why they had to surrender and open it when they were attacked by the invasion troops led by Toshiie Maeda. After that, the castle was eventually abandoned.
The Portrait of Hideyoshi Toyotomi, attributed to Mitsunobu Kano, owned by Kodaiji Temple (licensed under Public Domain via Wikimedia Commons)Odawara Castle
The castle of Narimasa Nagano, the strongest general
Location and History
Nagano Clan builds Castle in Sengoku Period
Minowa Castle was located on a hill at the foot of Mt, Haruna in Kozuke Province which is now Gunma Prefecture. The Nagano Clan first built this castle at the start of the 16th Century during the Sengoku Period. The clan was thought to originally be an official family of the local government in the ancient times, and eventually became a powerful local lord in the Middle Ages. They had lived near the Provincial Office on a plain land in the center of the province. However, it got dangerous to continue to do so, because many battles happened all over the Kanto Region since the late 15th Century. That’s why the clan built the castle beside the mountain area near western part of the province.
The location of the castle
Narimasa Nagano fights alone
The Nagano Clan worked under the Uesugi Clan, the governor of Kozuke Province. Norimasa Uesugi, the lord of the clan at that time, was defeated by the Hojo Clan from the south in the Battle of Kawagoe Castle in 1546. After that, he escaped from Kozuke Province to Echigo Provence in the north of the Kozuke Province. As a result, most of the local lords supported the Hojo Clan. However, Narimasa Nagano who was the lord of the clan, didn’t do so, showing his loyalty to the Uesugi Clan. He was considered as one of the strongest generals at that time, against large warlords such as the Hojo and Takeda Clans. He organized a group of local lords in the region, called the Minowa Group, to maintain their territories. He even accommodated some other generals who lost their territories due to defeats of battles, such as Yukitaka Sanada.
The wooden statue of Narimasa Nagano, owned by Chojunji Temple, quoted from the website of Takasaki CityThe portrait of Yukitaka Sanada, owned by Chokokuji Temple (licensed under Public Domain via Wikimedia Commons)
After some years of his binding time, Kenshin Uesugi, the successor of Norimasa, invaded the Kanto Region including Kozuke Province from Echigo Province in 1560. Narimasa became one of senior vassals of the Uesugi Clan again and succeeded to be the lord of the western Kozuke Province. However, when Kenshin returned to his home base, Kasugayama Castle in Echigo Province, the Hojo Clan started to get the territories back. In addition, Narimasa tried to subject the Obata Clan in Kunimine Castle to the southwest of Narimasa’s territory, but failed. This was because Nobuzane Obata, the lord of the clan, asked Shingen Takeda, one of the greatest warlords, for help and became his retainer. Yukitaka Sanada, who was saved by Narimasa, also became a senior vassal of Shingen after leaving Narimasa. Shingen was a lifetime competitor of Kenshin, so he started to invade the western Kozuke in 1561.
The portrait of Kenshin Uesugi, owned by the Uesugi Shrine (licensed under Public Domain via Wikimedia Commons)The imaginary drawing of Kunimine Castle, exhibited by Kanra Town Museum of History and FolkloreNorizane Obata drawn in the “Battle of Nagashino” folding screens, exhibited by Kanra Town Museum of History and FolkloreThe portrait of Shingen Takeda, owned by Jimyo-in Temple (licensed under Public Domain via Wikimedia Commons)
Castle falls with Destruction of Nagano Clan
Narimasa could somehow maintain Minowa Castle and the area around in his life, but died of illness in 1561. His son, Narimori Nagano followed his father’s way not to surrendering to their enemies. However, Shingen did a full-scale attack on Minowa Castle in 1566 before the castle fell. Narimori and his relatives fought to the end and finally killed themselves in the Gozen Enclosure of the castle. It is said that they threw the memorial tablets of their ancestors into the well in the enclosure before their deaths.
The family crest of the Nagano Clan, called Hiogi or A fan made of woodThe ruins of well in the Gozen Enclosure of Minowa Castle
After that, Nobuzane Obata changed their master to the Oda and Hojo Clans to maintain their territory after the destruction of the Takeda Clan. In 1590, when the ruler, Hideyoshi Toyotomi invaded Hojo’s Kanto Region, Obata’s own castle fell, then the clan loss their territory as well. On the other hand, the Sanada Clan struggled to be independently based in Ueda, Numata and Iwabitsu Castles. They finally succeeded to achieve this, however it was very hard to climb.
Ueda CastleThe ruins of Numata CastleThe miniature model of Iwabitsu Castle at the information center at the site
Naomasa Ii modernizes and abandons Castle
After Minowa Castle fell, the Takeda Clan owned the castle, followed by the Oda, Hojo and Tokugawa Clans. Naomasa Ii, the head of senior vassals of the Tokugawa Clan, was the last lord of the caste. He entered the castle when the Tokugawa Clan was moved to the Kanto Region in 1590. Minowa Castle was large, but originally had enclosures mainly made of soil, surrounded by dry moats. Naomasa improved and modernized the castle as much as he could. For example, he developed new enclosures such as the Inari Enclosure with a water moat to be more defensive. Stone walls were built alongside the Main Route to show the castle lord’s authority. Some turret gates were also built in the important positions of the castle, such as the Kaku-umadashi Western Entrance Gate. However, Naomasa finally moved to his new home base called Takasaki Castle on a plain land in 1598 before Minowa Castle was abandoned.
The portrait of Naomasa Ii, owned by Hikone Castle Museum (licensed under Public Domain via Wikimedia Commons)The Inari EnclosureThe restored Kaku-umadashi Western Entrance GateThe stone walls of the Third Enclosure Gate Ruins
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.
