16.Minowa Castle Part1

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 City
The 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 Folklore
Norizane Obata drawn in the “Battle of Nagashino” folding screens, exhibited by Kanra Town Museum of History and Folklore
The 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 wood
The 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 Castle
The ruins of Numata Castle
The 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 Enclosure
The restored Kaku-umadashi Western Entrance Gate
The stone walls of the Third Enclosure Gate Ruins

To be continued in “Minowa Castle Part2”

117.岩櫃城(Iwabitsu Castle)

岩櫃城は、防りが固そうに見えますが、実は攻撃のための城なのです。
Iwabitsu Castle looks like defensive, but actually aggressive.

岩櫃山と潜龍院跡(Mt. Iwabitsu and the ruins of Senryuin)

Location and History

過去において信濃国(現在の長野県)と上野国(群馬県)の間を結ぶ街道がいくつかありました。最も有名なのは中山道ですが、その他の一つとして信州街道があり、信濃の上田と上野の沼田をつないでいました(現在の国道145号線に相当します)。戦国時代の後半に武田氏配下であった真田氏は、この信州街道に沿って信濃から上野に向けて攻撃を仕掛けました。岩櫃城はこの途上にあり、真田氏が改修を行い、上野攻略のための重要拠点としました。
There were several roads between Shinano Proivnce (now called Nagano Prefecture) and Kozuke Province (Gunma Prefecture) in the past. The most famous one was Nakasendo, and one of the others was Shinshu-Kaido connecting Ueda in Shinano and Numata in Koduke (equivalent to current the National Route 145). In the late Warring States Period, the Sanada clan under the Takeda clan attacked from Shinano to Koduke along this Shinshu-Kaido. Iwabitsu Castle was on the way, renovated by the Sanada clan to be an important site for the capture of Koduke.


国道145号線の周辺地図と岩櫃城の位置(The map around National Route 145 and the location of Iwabitsu Castle)

この城は岩櫃山にありましたが、山頂ではありませんでした。そこは岩山で危険であったからです(現在でも登頂には登山の装備が必要です)。それで城の中心は、山の中腹にありました。つまり、城の背後は自然の要害である岩山により守られていたということです。また、もう一つの障壁として吾妻川にも守られていました。
The castle was located on Mt.Iwabitsu, but not on the top, because the spot is too rocky and dangerous to stay (Even now, climbing to the top requires a modern climbing equipment). So the center of the castle was halfway up the mountain. This means that the behind the castle was protected by rock as a natural hazard. The castle also had another hazard, the Agatsuma River.

現地案内所にある城のミニチュアモデル(The miniature model of the castle at the information center at the site)

この城は最初は南北朝時代に土豪により作られたと言われています。その後真田幸隆が大変な苦労をしてこの城を手に入れました。そして彼の息子である真田昌幸が改修したのです。
It is said the castle was first built in the North-South Court Period by a local clan. After that, Yukitaka Sanada got it with great difficulty. His son, Masayuki Sanada renovated it.

真田昌幸像、個人蔵(The portlait of Masayuki Sanada, privately owned)licensed under Public Domain, via Wikimedia Commons

1582年3月、真田の主君である武田勝頼は織田信長の侵攻により滅亡の危機を迎えていました。昌幸は、勝頼をこの城に迎え入れ、支えていくことを考えました。彼はまた、勝頼のために山の麓に館を作りました(現在の潜龍院跡)。しかしながら、勝頼がすぐに死んでしまったため、計画は実現しませんでした。
Sanada’s master, Katsuyori Takeda faced the crisis of destruction due to Nobunaga Oda’s invasion in March 1582. Masayuki thought about accommodating and supporting the master in this castle. He built the hall for Katsuyori at the foot of the mountain as well(What is now called “the ruins of Senryuin”).However, it didn’t happen as Katsuyori died shortly.

潜龍院跡(The ruins of Senryuin)

一方、真田は何とかこの城を維持することができましたが、戦国時代が終わったとき、この城は必要がなくなったため、1614年に昌幸の息子、真田信之により廃城とされました。
On the other hand, Sanada somehow manage to keep this castle. When the Warring States Period ended, the castle was not needed, and was abandoned by Masayuki’s son, Nobuyuki Sanada in 1614.

真田信之像、個人蔵(The portlait of Nobuyuki Sanada, privately owned)licensed under Public Domain, via Wikimedia Commons

Features

岩櫃山は南に向かって岩の頂が際立っていますが、城跡は北西の方向に向いており、山の背後に残されています。城跡は、山の尾根の上にあり、そこから「本丸」「二の丸」「中城」といった曲輪が広がっており、それらもまた自然の障壁に守られていました。
Mt.Iwabitsu has a great rocky looking part facing the south, but the castle ruins remain at back of the mountain facing the north east direction. They are on a ridge of the mountain spreading down several enclosures called “Honmaru”, “Ninomaru” and “Nakashiro” surrounded by natural hazards.

岩櫃山の正面(The front of Mt. Iwabitsu)

城跡の麓にたどり着くには、たった一本の細く曲がりくねった道しかありません。その入り口はまた「柳沢城」という支城によっても守られていました。
There is only one narrow and winding road to reach the foot of the ruins. The entrance was also protected by the branch castle called “Yanagisawa Castle”.

城跡への道(The road to the ruins)

ここまで聞くと、この城は守りがとても固いと思われるでしょうが、この城には別の側面もあるのです。まず、尾根の上の曲輪は空堀や溝により区切られていますが、まるでネットワークのようです。これらは敵を防ぐためだけではなく、連絡のためにも使われたようです。
You may feel the castle was very defensive, however it had a different perspective. First, enclosures on the ridge are separated by dry moats or ditches like network. The network seemed to be used not only for preventing enemies, but also for connection.

空堀、兼通路(Dry moats or passages)

この城にはまた、山麓に天狗丸と呼ばれる曲輪と城下町があり、多くの兵士や住民を収容できました。
The castle also had an enclosure called Tengu-Maru and the castle town at the foot that could accommodate a large numbers of soldiers or residents.

天狗丸跡(The ruins of Tengu-Maru)

更には、尾根の上の本丸はそれ程大きくなく、指令所として使われたのではないでしょうか。
In addition, Honmaru on the ridge is not so large that might be used for the headquarter.

本丸跡(The ruins of Honmaru)

つまるところ、この城は真田の攻撃拠点として使われたと思うのです。郷土史家の山崎一は、このような城のレイアウト(縄張り)を「陽の縄」と言っています。
Overall, I think the castle was used for Sanada’s base to attack. Hajime Yamazaki, a local historian says that such a layout is called a bright layout “You-no-Nawa”.

二の丸から本丸を見上げる(Lookimg up Honmaru from Ninomaru)

Later Life

この城の立地のこともあり、廃城後の岩櫃城の遺跡は長い間そのまま放置されてきました。山崎氏が最初に城跡を調査したのは、1970年代のことでした。彼は調査の結果を公表し、それがきっかけで城跡は1972年に町の史跡に指定されました。そしてつい最近の2019年10月に国の史跡にも指定されました。これからこの城跡がどうのように整備されるのかとても楽しみです。
Because of its location, the ruins of Iwabitsu Castle had been left as they were for a long time after being abandoned. Yamazaki first investigated the ruins in the 1970s. He published his achievement, then the ruins were designated as a local historic site in 1972. They also became a national historic site just recently in October 2019. I’m looking forward to seeing how they are developed in the future.

本丸にある岩櫃城の標柱(The signpost of Iwabitsu Castle at Honmaru)

My Impression

歴史に「もしも」はないと言われますが、多くの歴史ファンはもし勝頼が岩櫃城に来ていたらどうなっていただろうと空想を逞しくしています。私ももしそうであれば、武田と織田の戦いは長引いたと思うのです。この城であれば大軍を前にしばらくは持ちこたえられるからです。そうしたら、歴史は史実と変わっていたでしょう。なぜなら信長の予想外の大勝利は彼を自己満足や自信過剰に陥らせたからです。それが、この勝利からわずか3ヶ月後の本能寺の変での彼の死につながったのです。
It is said that there is no “if” in history. But many history fans enjoy speculating what would happen if Katsuyori came to Iwabitsu Castle. I imagine the battle between Takeda and Oda would be longer as the castle could hold out against large troops for a while. Then, history might change from that fact, because Nobunaga’s unexpected great victory made him complacent and overconfident. That led to his death in the Honnoji Incident in June 1582, just three months after the victory.

岩櫃山の麓にある潜龍院跡(The ruins of Senryuin on the foot of Mt. Iwabitsu)

How to get There

岩櫃城跡へは:車の場合は、平沢登山口に駐車してください。電車の場合はJR吾妻線群馬原町駅から駐車場まで歩いて約40分です。駐車場から本丸までは更に歩いて約20分です。
To the ruins of Iwabitsu Castle: When using car, park at the Hirasawa starting point for a climb. When using train, it takes about 40 minutes on foot from the Gunma-Haramachi station on JR Agatsuma line to the parking lot. it takes another about 20 minutes on foot from the parking lot to Honmaru.

潜龍院跡へは:車の場合は、古谷登山口に駐車してください。電車の場合はJR吾妻線郷原駅から駐車場まで歩いて約20分です。駐車場から潜龍院跡までは更に歩いて約15分です。
To the ruins of Senryuin: When using car, park at the Furuya starting point for a climb. When using train, it takes about 20 minutes on foot from the Gobara station on JR Agatsuma line to the parking lot. it takes another about 15 minutes on foot from the parking lot to the ruins.

東京駅から群馬原町駅または郷原駅まで:上越新幹線に乗り、高崎駅で吾妻線に乗り換えてください。
From Tokyo to Gunma-Haramachi or Gobara station: Take the J0etsu Shinkansen super express to Takasaki station, and transffer to Agatsuma local line.

Links and References

岩櫃なび(Iwabitsu Navi, only Japanese?)
・「群馬の古城 北毛編/山崎一」あかぎ出版(Japanese Book)
・「真田太平記 1岩櫃の城/池波正太郎」朝日新聞社(Japanese Book)