Oshi Castle

Japanese: 忍城 - おしじょう

This medieval castle was located in Gyoda City, Saitama Prefecture, and was the headquarters of the Oshi clan during the Edo period. It is a designated historic site by the prefecture. It is one of the Seven Great Castles of Kanto. It is said that the castle was built around 1478 (Bunmei 10) by the local powerful Narita Masato and his son Akiyasu after they destroyed the Oshi clan, who belonged to the Ogigayatsu Uesugi clan, and it became the residence castle of the Narita clan. The castle was built on a flat land using a marshland, and there were islands of land scattered in the marsh nearby, and the castle was built to make use of these marshes. The lord of the castle, the Narita clan, rebelled against the influence of the Hojo clan of Odawara that extended into Musashi Province, and Hojo Ujiyasu attacked the castle in 1553 (Tenbun 22), but failed. The Narita clan followed Nagao Kagetora (later Uesugi Kenshin) of Echigo, who invaded Kanto in 1559 (Eiroku 2). However, after the siege of Odawara Castle in 1561 (Eiroku 4), at the inauguration ceremony of Uesugi Kenshin as Kanto Kanrei held at Tsurugaoka Hachimangu Shrine in Kamakura, the lord of the castle at the time, Narita Nagayasu, was reprimanded by Kenshin for his rudeness, and he defected from the Uesugi clan and joined the Hojo clan. During Toyotomi Hideyoshi's siege of the Hojo clan in 1590 (Tensho 18), the lord of the castle, Narita Ujinaga, barricaded himself in Odawara Castle (Odawara City, Kanagawa Prefecture), but his retainers and nearby farmers barricaded themselves in Oshi Castle and fought against the Toyotomi forces led by Ishida Mitsunari. Mitsunari built a 28km-long embankment and attempted to siege the castle with water, but failed to take it, and opened the castle after the fall of Odawara Castle. The castle is also known as Oshi's Floating Castle, which comes from this battle. When Tokugawa Ieyasu entered the Kanto region, his fourth son, Matsudaira Tadakichi, entered the castle, and it served as the headquarters of the Oshi clan until the abolition of the feudal domains and the establishment of prefectures in the Meiji period. Following the abolition of the feudal domains and the establishment of prefectures, the prefectural office of Oshi prefecture was established in the Ninomaru of the castle, but it was later abandoned and most of the structures within the castle were destroyed. Currently, the castle ruins are Oshi Park, and part of the earthworks surrounding the castle remain. After the war, Gyoda City Honmaru Baseball Stadium was built on the site of the main citadel, but the stadium has since been relocated and the Gyoda City Local History Museum stands on the site of the stadium. As one of the facilities of the museum, the Gosanga Yagura (three-story turret) from the Edo period (with an exhibition hall inside) was restored, but the location and shape of the turret differ from the historical facts. In addition, the former Kitayamon Gate was moved to Soganji Temple in Kazo City, Hyogo Prefecture, and still stands today. In addition, to the south of the local museum is the gate of the domain school, Shinshukan, and next to the parking lot of the museum is the castle gate, which was moved and remains to this day, although it is unclear where it was located. Take a bus from Gyoda Station, Fukiage Station, or Kumagaya Station on the JR Takasaki Line and get off at Oshi Castle. Or it is about a 15-minute walk from Gyoda City Station on the Chichibu Railway. ◇It is also called the floating castle of Oshi, or the turtle castle.

Source: Kodansha Encyclopedia of Japanese Castles Information

Japanese:

埼玉県行田市にあった中世の平城(ひらじろ)で、江戸時代には忍藩の藩庁が置かれた。同県指定旧跡。関東七名城の一つ。1478年（文明10）ごろに、地元の豪族の成田正等・顕泰父子が扇谷上杉氏に属していた忍一族を滅ぼして築城したとされる。以後、成田氏の居城となった。湿地帯を利用してつくられた平城で、付近は沼の中に島のような陸地が点在していたが、この沼をそのまま生かすかたちで城が築かれた。城主の成田氏は、小田原の北条氏の勢力が武蔵国に及んでくるとこれに反発し、北条氏康は1553年（天文22）に同城を攻めたが攻略に失敗している。成田氏は1559年（永禄2）に関東に遠征した越後の長尾景虎（のちの上杉謙信）に従った。しかし、1561年（永禄4）の小田原城攻めの後に鎌倉の鶴岡八幡宮で行われた上杉謙信の関東管領の就任式で、当時の城主の成田長泰が謙信から無礼を咎められたために上杉氏と離反し、北条氏に属した。1590年（天正18）の豊臣秀吉の北条氏攻め（小田原の役）の際、城主の成田氏長は小田原城（神奈川県小田原市）に篭城したが、家臣や付近の農民が忍城に立てこもり、石田三成を大将とする豊臣方と戦った。三成は同城の守りが固いことから、長さ28kmにおよぶ堤を建設して水攻めを行ったが落城せず、小田原城の落城後に開城した。同城には忍の浮き城という別称があるが、これはこの戦いを由来とする。徳川家康が関東に入部すると、同城には家康四男の松平忠吉が入城し、これ以降、明治の廃藩置県まで忍藩の藩庁となった。廃藩置県にともない、同城二の丸に忍県の県庁が置かれたが、その後、廃城となり、城内にあった構造物のほとんどは破壊された。現在、城跡は忍公園になっており、同城の周囲にあった土塁の一部が残っている。戦後、本丸跡に行田市本丸球場が建設されたが、現在は球場は移転し、球場跡には行田市郷土博物館が建っている。同博物館の施設の一つとして、江戸時代の御三階櫓(ごさんがいやぐら)（内部は展示館になっている）が復元されたが、位置や櫓の形状は史実と異なる。また、近郊の同県加須市の総願寺にかつての北谷門が移築され現存している。また、郷土博物館の南側に藩校進修館の門が、また同博物館の駐車場脇には、かつてどこにあった門かは明らかではないが同城の城門が移築され現存している。JR高崎線行田駅、吹上駅、熊谷駅からバスで忍城下車。または秩父鉄道行田市駅から徒歩約15分。◇忍の浮き城、亀城とも呼ばれる。

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