Shinpu Castle was located in what is now Nirasaki City, the northwest part of Yamanashi Prefecture which was called Kai Province. The province was owned by the Takeda Clan for a long time until the late 16th Century and their home base had been located in the Takeda Clan Hall in Kofu, the center of the province. Katsuyori Takeda, the last lord of the clan decided to move his home base to Shinpu Castle in 1581. He moved to the castle within the year.
The location of the castle
The Portrait of Katsuyori Takeda, ownd by Koyasan Jimyoin (licensed under Public Domain via Wikimedia Commons)The ruins of Takeda Clan Hall
The move was done for several reasons. First, Takeda’s territory expanded to the west such as Shinano Province (now Nagano Pref.), in order to make Shinpu Castle the center of their territory. Secondly, the large territory made Takeda’s vassals so many that the Takeda Clan Hall and Kofu were too narrow and small for them. Lastly, Katsuyori was threatened by Nobunaga Oda and Ieyasu Tokugawa from the west, after several defeated battles with them such as those of Nagashino Castle and Takatenjin Castle. Katsuyori needed to prepare a stronger castle for a possible invasion from them.
The location of Shinpu Castle and the range of Shinano Provence (on the left) and Kai Province (on the right)
The ruins of Nagashino Castle
Final version of Takeda Clan’s Method for building Castles
Shinpu Castle was built on a mountain on a long cliff wall called Shichiri-Iwa, which means about 28km long rock, along the Kamanashigawa River on the westerly direction. The eastern side of the castle was also a steep cliff of the mountain. The southern part of the castle had the Main Gate with the large Umadashi which was Takeda’s characteristic defense system. The northern part had this castle’s unique defense system called Degamae with water moats. The back entrance had doubled gates with a square space inside called Masugata. The Main Enclosure, the Second Enclosure, and the Third Enclosure were placed on several tiers to protect the castle. Katsuyori’s Main Hall was built in the Main Enclosure on the top. Overall, the castle could be very defensive even though it was all made of soil.
The relief map around the castle
The imaginary drawing of Shinpu Castle (from the signboard at the site)
However, Katsuyori burned the castle by himself and escaped from it in Mar 1582 after only his three-month stay, when he had heard of Takato Castle, located in the west of Shinpu Castle, being captured by Nobunaga’s invasion. Moreover, Katsuyori was defeated by his retainer’s betrayal just after eight days from the escape. So, why did Katsuyori withdraw from the castle?
The positional relation between Shinpu Castle and Takato Castle
The ruins of Takato Castle
Why did Katsuyori throw Castle away?
The reason which had been often said was that the castle was still unfinished. For example, the Main Gate was found to have no buildings through excavation. Others point out that Katsyori had only hundreds of his troops including women and children when they escaped because most of his vassals left him. Some remaining senior vassals recommended that he should be accommodated to another castle. For example, Masayuki Sanada offered Sanada’s Iwabitsu Castle in Kozuke Province (now Gunma Pref.). Katsuyori finally took another suggestion from the retainer who would deceive him. Another historian even says Sinpu Castle maybe did not deserve a castle, but a large hall would have been more suitable. This is because it needed more moats for a castle. Only Katsuyori knew the answer.
The portlait of Masayuki Sanada, privately owned licensed under Public Domain, via Wikimedia Commons)The ruins of Iwabitsu Castle
After Nobunaga was also killed in the Honnoji Incident in June 1582, Ieyasu used Sinpu Castle again for his stronghold to get Kai Province. He succeeded in getting it, used Takeda Clan Hall to govern it, and built Kofu Castle as its new home base before Shinpu Castle was eventually abandoned.
The Portrait of Ieyasu Tokugawa, attributed to Tanyu Kano, ownd by Osaka Castle Museum (licensed under Public Domain via Wikimedia Commons)The ruins of Kofu 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.
沼田城は真田がこだわり続け、しかし最後には失った城です。 Numata Castle is the one that Sanada stuck to strongly, but lost in the end.
沼田城西櫓跡（The ruins of Nishi-Yagura of Numata Castle）
Location and History
群馬県の北部に位置する沼田市は、全国的に河岸段丘の地形で有名です。その高さは、ＪＲ沼田駅近くの利根川から７０メートル以上になります。市街地はその段丘の上にあり、「天空の城下町」と呼ばれています。 Numata City, in the northern part of Gunma pref., is famous around the whole country for its terrain with river terraces. The height is over 70m higher than Tone River near the JR Numata Station. The urban area of the city is on the top of the terraces and now called “Castle Town in the Sky”.
沼田市の河岸段丘、左側が段状になっている（The river terraces in Numata City, they are on the left side）taken by igamania from photo AC
この辺り一帯が最初に注目されたのは恐らく、戦国時代の１６世紀頃、関東地方の支配権を巡って戦った上杉、北条、武田、織田、徳川などの有力戦国大名たちによってだと思われます。沼田地域は、関東地方の北の入り口にあたり、東の東北地方から西の信濃国（現在の長野県）に抜けていく主要街道が通っていました。 The area was probably first focused on in the Warring States Period in the 16th century by major warlords such as the Uesugi, Hojo, Takeda, Oda and Tokugawa clans who battled over the right to rule of the Kanto region . The Numata area was the northern entrance of Kanto and had a main road passing through from the east for Tohoku region to the west for Shinano Province (now Nagano pref.).
城周辺の地図及び起伏地図（A normal and relief map around Numata Castle）
沼田城は最初、土豪の沼田氏によって１５３２年に段丘の突端に築かれました。しかし、１５６０年の上杉氏の関東侵攻からは非常に重要な拠点として認識されました。結果的には、戦国時代の終わりにおいては武田氏配下の真田昌幸がこの城を保持していました。１５８２年には彼の主君である武田氏は滅びてしまうのですが、他の有力大名を差し置いて何とか城を守り抜きました。 Numata Castle was first built on the tip of the terrace in 1532 by the local clan Numata, but the castle became a very important site after the Uesugi’s Kanto invasion in 1560. Eventually, Masayuki Sanada under Takeda held the castle at the end of the Warring States Period. Though his master Takeda was beaten in 1582, he struggled against other major warlords to keep the castle.
真田昌幸像、個人蔵（The portlait of Masayuki Sanada, privately owned）licensed under Public Domain, via Wikimedia Commons
クライマックスは、１５８９年に天下人豊臣秀吉の裁断によって、この城が北条氏に引き渡されたときでした。何と真田は、１５９０年の秀吉の関東侵攻と、北条氏の滅亡により、城の奪還に成功します。この出来事は、北条が約束を破り、真田の名胡桃城を乗っ取ったからだと言われていますが、真相は謎のままです。死人に口なしだからです。 The climax was that the castle was turned over to Hojo in 1589 by the decision of the ruler, Hideyoshi Toyotomi. However, Sanada was successful to get it back after Toyotomi’s Kanto invasion and the fall of Hojo in 1590. It is said that the event was caused due to Hojo breaking the rule and taking Sanada’s Nagurumi Castle. The fact is mysterious because dead men tell no tales.
名胡桃城跡（The ruins of Nagurumi Castle）licensed by Qurren via Wikimedia Commons
その後、昌幸の息子、真田信之が徳川の下につき、この城を引き継ぎ１６００年前後に天守の建築を含め完成させました。この天守は、将軍がいる江戸城を除いては関東地方で唯一の５層の天守でした。 After that, Masayuki’s son Nobuyuki Sanada under Tokugawa inherited and completed the castle with building the castle Tenshu keep around 1600. The Tenshu was the only five-story one in Kanto region, excluding Edo Castle owned by the Shogun.
上野国沼田城絵図部分、江戸時代（Part of the illustration of Numata Castle in Kozuke Province in Edo Period）｜出典：国立公文書館
１６５８年に、真田一族の中でこの城の相続を巡ってお家騒動が起こりました。徳川幕府は、真田の分家である信利を沼田藩として、信濃国松代にあった真田本家より独立させる決定をしました。 There was internal trouble in the Sanada clan over the inheritance of the castle in 1658. The Tokugawa Shogunate decided to make the branch Sanada, Nobutoshi separate from the head Sanada in Matsushiro, Sinano Province as the Numata Domain.
真田信利肖像画、加納永泰筆、大法院蔵（The Portrait of Nobutoshi Sanada, attributed to Eitai Kano, ownd by Daihoin）licensed under Public Domain via Wikimedia Commons
信利は、幕府から困難な課役を引き受け、真田本家に対抗するため豪華な屋敷も造営しました。その結果沼田藩の領民は重い年貢に苦しみました。そして信利は、両国橋再建の資材調達に失敗したのと、農民の茂左衛門の幕府への直訴により、１６８１年に改易となってしまいました。ついには、真田があれほどまでこだわった沼田城は、１６８２年に幕府により完全に破壊されたのです。 Nobutoshi accepted hard tasks from Shogunate and built luxurious halls against the head Sanada. The result was that people in Numata Domain suffered from high taxes. Nobutoshi was fired in 1681 inspired by his failure of preparing materials for the Ryogoku Bridge rebuilding and the direct appeal to Shogunate by a farmer called Mozaemon. At last, Numata Castle that Sanada were so much devoted to, was completely destroyed by Shogunate in 1682.
天守があったと思われる場所（The place where there seemed be Tenshu）
Features
現在沼田城の城跡は、沼田公園として使われています。そこには美しい花々や木々による庭園があるのですが、西櫓の石垣が掘り出されたのと、復元された時計台が残っているのみです。 Now, the ruins of Numata castle have been turned into a park called the Numata Park. Though it has a beautiful flowers and trees garden, only unearthed stone walls of the west turret and the restored clock tower remain.
沼田公園（Numata Park）掘り出された西櫓石垣（The unearthen stone walls of the west turret）復元された時計台（The restored clock tower）
Later Life
真田の城が撤去された後、土岐氏などの大名が江戸時代の間この地域を支配しましたが、藩庁のための建物が設置されたのみでした。明治維新後その建物も撤去され、堀は埋められました。幸いだったのは元藩士の久米民之助が城跡を買い上げ、市に公園として寄付したことでした。 After Sanada’s castle was demolished, some lords like the Toki clan governed the area in the Edo Period. They just had a few office halls to govern. After the Meiji Restoration, the buildings of the castle were removed, and moats were filled. The good thing was that a former warrior Taminosuke Kume bought the ruins and donated them to the city for a park.
公園からの眺め（A view from the park）
現在、２０１６年に人気が出たＮＨＫ大河ドラマ「真田丸」が放送された後、沼田市には天守を復元できないか検討している人たちがいます。そのドラマは、真田氏、主には信之の弟、真田信繁の人生を描いたもので、信繁は大坂城で豊臣のために徳川と戦ったことで有名です。（真田氏は意図的に徳川方と豊臣方に分かれていました。）ドラマでは、沼田も取り上げられており、そのことが沼田市の観光振興にも寄与しました。 Now, some people in this city are considering how they could restore the Tenshu after a popular NHK drama called “Sanada-Maru” aired in Japan in 2016. The drama was about the lives of the Sanada clan, mainly about Nobushige Sanada, Nobuyuki’s little brother, famous for the fights with Tokugawa for Toyotomi in Osaka Castle. (Sanada clan were divided into Tokugawa and Toyotomi on purpose.) The drama which also featured Numata, led to an increase in tourism for the city.
現地案内板にある天守の想像図（The imaginary drawing of Tenshu on the sign board at the site）
市の人たちは、近い将来に人気が衰えてしまうのを心配しているようです。そして天守のような新しいシンボルを模索しており、白石城のような成功事例を視察したりしています。 People in the city seem worried about the decrease in the near future. They are searching for a new symbol like the Tenshu, and researching successful cases such as the Shiroishi Castle.
復元された白石城（The restored Shiroishi Castle）
しかしながら実現にはいくつもの大きな問題があります。まず、早々に城が破壊されたため天守の詳細が全くわかりません。現在のところ本丸石垣と、金箔瓦や什器などいくつかの品が発掘されたのみです。加えて文化庁が各地方自治体に明確な根拠なしに歴史的建造物を安易に復元しないよう指導している事情もあります。次として莫大な予算が必要です。もし天守を伝統的木造建築のスタイルで再建する場合、市の年間一般会計予算に匹敵する資金が必要となります。実に悩ましい問題です。 However, there will be big problems that come with it. At first, the details are not clear at all because of the castle being destroyed. Stone walls of Honmaru, and few items like roof tiles with gold leaf and utensils have been excavated so far. In addition, the Agency for Cultural Affairs instructs local governments not to restore historical buildings without clear evidence. Secondly it needs a large budget. If they ever decide to construct the Tenshu in a traditional wooden style, it will require a fund as much as their annual general budget. That is too controversial.
発掘された本丸石垣（The excavated stone walls of Honmaru）
市は、自らを「真田の里」として売り出しています。これからどんな展開になるか注目したいと思います。 The city is also trying to identify itself as “Sanada’s Hometown”. I will keep watching what they are doing now.
My Impression
人気を維持するためまず考えられるのは、大坂城、上田城、名胡桃城、岩櫃城など真田にまつわる城や城跡を持つ自治体と連携してイベントを開くことだと思います。 To keep the population, I think that a reasonable idea is holding events together with other municipalities having relative castles and ruins to Sanada such as Osaka, Ueda, Nagurumi and Iwabitsu.
大坂城（Osaka Castle）上田城（Ueda Castle）
そして、可能性がある方法としては、発掘の結果を基に門か櫓を再建することです。例えば、鉢形城などが類似のケースでしょう。 Then, one possible solution could be rebuilding a gate or a turret based on excavation. There are similar cases, for example in Hachigata.
鉢形城の再建された門（The rebuilt gate in Hachigata Castle）
もう一つの可能性として、大分府内城のようにＬＥＤを使って仮想天守の姿を創り出してはいかがでしょう。 For another possibility, how about creating the image of virtual Tenshu with LED like Oita-Funai.
大分府内城の仮想天守（The virtual Tenchu in Oita-Funai Castle）taken by ぴょんにゃん from photo AC
But if they actually want to construct a real Tenshu building, they might have to be prepared for using it as their office hall. でも、もし本当に本物の天守を作りたいのであれば、市役所の建物に使うくらいの覚悟が必要なのではないでしょうか。
How to get There
沼田城跡に行くには車が便利です。関越自動車道の沼田ＩＣから約１０分です。電車を使う場合は、ＪＲ沼田駅から歩いて約２０分かかります。河岸段丘の急坂を登っていく必要がありますが、それも面白いかもしれません。
東京から沼田駅まで：上越新幹線に乗って高崎まで行き、上越線に乗り換えてください。
It is useful to access Numata Castle Ruins by car. It takes about 10 minutes from Numata IC on Kan-Etsu Expressway. When using train, it takes about 20 minutes on foot from JR Numata Station. It needs to climb up a steep hill on the river terraces, but it may be interesting.
From Tokyo to Numata Station: Take the Jo-Etsu Shinkansen super express to Takasaki, then transfer to Jo-Etsu local line.
