The Siege of Nanao Castle occurred from the eleventh month of Tenshō 4 (1576) to the ninth month of Tenshō 5 (1577).  The conflict was waged between the army of Uesugi Kenshin of Echigo Province and Chō Tsugutsura, a senior retainer of the Noto-Hatakeyama clan at Nanao Castle in the Kashima District of Noto Province.  Victory by the Uesugi resulted in their control of the province.

Relationship between the Oda and Uesugi clans

In 1572, owing to a campaign known as the Encirclement of Nobunaga orchestrated behind the scenes by Ashikaga Yoshiaki, Nobunaga struggled against the forces opposed to him.  To counter Takeda Shingen, the sengoku daimyō of Kai Province, applying pressure from the east in an expedition known as the Western Campaign, Nobunaga entered into an alliance with Uesugi Kenshin of Echigo Province who was similarly opposed to Shingen.  Nobunaga and Kenshin also held a shared interest in confronting the Ikkō-ikki forces in Ise and Etchū provinces.

On 4/12 of Genki 4 (1573), after Shingen died of illness during the Western Campaign, the situation dramatically changed.  Two years earlier, Hōjō Ujiyasu died.  The elimination of these two arch enemies reduced the need to focus on the Kantō.  Instead, with a continuation of uprisings in Etchū and Kaga provinces, the members of the Ikkō sect became the chief enemy.  Consequently, in 1574, after deploying to the Kantō and fighting against Hōjō Ujimasa, Uesugi Kenshin delegated the Kantō to Hōjō Takahiro and Hōjō Kagehiro (father and son) based at Mayabashi Castle in Kōzuke Province.  Thereafter, he aimed to expand his influence in the Hokuriku.

In the fifth month of 1575, Nobunaga defeated Takeda Katsuyori at the Battle of Nagashino and, in the eighth month, ordered Shibata Katsuie to invade Echizen Province.  At the time, the province was controlled by the Ishiyama-Hongan Temple.  Nonbunaga had their commander in chief in Echizen, Shimotsuma Raishō, and 12,000 followers executed.  As a result, the Ishiyama-Hongan Temple confronted a crises so, in the sixth month of 1574, requested the support of Kenshin.  In the ninth month, remaining forces of the Ikkō-ikki appealed for support from Kawada Nagachika of Toyama Castle in Etchū.  In addition to these demands, owing to a clash between his interests and the real crisis caused by the expansion of influence by Nobunaga in the Hokuriku, in the second month of 1576, Kenshin broke his alliance with Nobunaga.  In the fifth month, through the mediation of Ashikaga Yoshiaki, he reconciled with Kennyo, formed an alliance, and became a member of the power opposed to Nobunaga.

Course of events

Internal conflict in the Noto-Hatakeyama clan

In the ninth month of 1576, Kenshin led 20,000 troops to invade neighboring Etchū Province.  Originally, the Noto-Hatakeyama family of Kawachi served as the military governors of Etchū, but, in the Sengoku period, deputy military governors such as the Jinbō and Shiina clans acquired power and competed among themselves for dominance.  In 1566, Hatakeyama Yoshitsuna was ousted by his band of retainers.  In the second month of 1574, Hatakeyama Yoshinori (who was backed as the successor to Yoshitsuna) met an untimely death.  Based on one theory, he was assassinated by retainers including Yusa Tsugumitsu and Nukui Kagetaka.  Yoshinori was, in turn, succeeded by his younger brother, Hatakeyama Yoshitaka, who died in 1576.  In the end, Yoshitaka’s young son, Hatakeyama Haruōmaru, was backed as his successor, but the real authority was held by a senior retainer, Chō Tsugutsura. In order to promote stability in Noto, Jōjō Masashige was backed as the next head of the Hatakeyama clan who had earlier been tendered by the Hatakeyama as hostage.

First Siege of Nanao Castle

これに対して能登畠山家中は謙信の介入を嫌い、対決する姿勢を鮮明にした。七尾城内では老臣筆頭の長続連以下兵2000での籠城戦と決定する。続連が七尾城の大手口、温井景隆が古府谷、遊佐続光が蹴落口をそれぞれ守備することを決めた。さらに続連は謙信の背後を撹乱するために、笠師村や土川村、長浦村などの領民に対して一揆を起こすように扇動したのである。ところが、謙信もかつて一向一揆に悩まされた経験から一揆に関する情報網があり、これらを全て鎮圧した上で七尾城を囲んだ。しかし、七尾城は畠山義総によって築かれた難攻不落さで縄張りも広く、春日山城にも匹敵する堅城だったためさすがの謙信も攻めあぐねていた。そこで七尾城を孤立させるためにその支城群に矛先を転じた。鹿島郡中島町谷内にある熊木城、珠洲市正院町川尻の黒滝城をはじめ、羽咋郡富来町八幡の富来城、羽咋郡富来町の城ヶ根山城、羽咋市柳田町にある粟生七郎の粟生城、鳳至郡柳田村国光にある牧野上総介の米山城などが、あっという間に落城し七尾城は孤立した。しかしそれでも、堅城を頼む七尾城の続連らは降伏しなかった。

越年して天正5年(1577年)に入り、3月に北条氏政が北関東方面に出兵したため、謙信は本国の仕置を兼ねていったん越後に帰国した。このとき、謙信は熊木城に三宝寺平四郎と斉藤帯刀・内藤久弥・七杉小伝次を、黒滝城に長景連を、穴水城に長沢光国と白小田善兵衛を、甲山城に轡田肥後と平子和泉を、富来城に藍浦長門を、石動山に上条織部と畠山将監をそれぞれ配置した。

謙信が越後に帰国すると、七尾城にあった畠山軍は即座に反撃を開始した。熊木城は畠山の家臣・甲斐庄親家の謀略で誘いに乗った斉藤帯刀が裏切りを起こし落城、七杉小伝次は自害し、三宝寺平四郎と内藤久弥は討ち死にした。富来城にも畠山の家臣・杉原和泉を総大将とした軍が押し寄せ、藍浦長門は捕らえられて処刑された。また、続連自身も自らの居城であった穴水城を奪還すべく出陣するなど、畠山軍は上杉留守部隊に攻勢をかけた。

Second Siege of Nanao Castle

閏7月、北条軍の侵攻は大規模なものではなく、領国の仕置を済ませた謙信は再び能登に出陣した。驚いた続連は、慌てて奪い返した各地の城を放棄して全兵力を以って七尾城に籠もった。さらにこの時続連は領民に対して徹底抗戦を呼びかけ、半ば強制的に領民を七尾城に籠もらせたのである。このため、城内は兵士と領民合わせて1万5000人近くの大人数となった。ちなみに、このように七尾城で慌てて再び籠城戦の準備がなされていたとき、穴水城の長沢光国と甲山城の轡田肥後が七尾に攻め寄せたが、逆に敗退している。

続連は謙信の再出兵に危機感を強め、僧籍にあった息子の長連龍安土城の織田信長の許に使者として派遣し、援軍を要請した。信長は要請を了承し、8月8日に柴田勝家を総大将とした織田軍を能登に派遣した

謙信は8月9日に織田軍の越前出兵を知り、加賀の一向宗の総領である七里頼周に対して救援を求める書状を送って織田軍の進軍妨害を求め、また石動山に本陣を置いて七尾城攻略を急いだ。

七尾城は堅城であったが、籠城戦が続く中、城内で疫病が起こり、畠山軍の兵士たちは戦いではなく、疫病で死ぬ者が相次いだ。幼君の畠山春王丸も籠城中に疫病で死去してしまった。窮した続連は小伊勢村の八郎右衛門に上杉軍に対して一揆を起こすように扇動した。ところが一揆はまたもや謙信によって事前に封じ込まれ、七尾城は落城寸前となった。

このような中で、かねてから親謙信派であった遊佐続光は、かねてからの謙信の呼びかけに応じ、仲間の温井景隆や三宅長盛兄弟らと結託して内応しようとしていた。もともと彼らは、親信長派として実権を自分たちから奪った続連を快く思わず、しかもこのまま抗戦しても勝機が無いと踏んだからである。遊佐・温井らは9月13日付で謙信に対して内応了承の書状を送った。この日は中秋の名月の日で、本陣で月見の宴を催していた謙信は「霜満軍営秋気清(霜は軍営に満ちて秋気清し)。数行過雁月三更(数行の過雁月三更)。越山併得能州景(越山併せ得たり能州の景)。遮莫家郷憶遠征(さもあらばあれ家郷遠征を憶うは)」という七言絶句、いわゆる『十三夜の詩』を口にしたと伝わっている

9月15日、遊佐・温井・三宅らは十五夜の月の日に城内で反乱を起こし、城門を開けて上杉軍を招き入れた。この反乱によって続連とその子・長綱連、さらに綱連の弟・長則直や綱連の子・竹松丸と弥九郎ら長一族100余人はことごとく討たれてしまった。長一族で唯一生き残ったのは、信長のもとに援軍を要請に行った連龍と、綱連の末子である菊末丸のみであった。こうして七尾城は謙信の手に落ちた。能登も完全に謙信の支配下に入った。

Aftermath

Around this time, reinforcements led by Shibata Katsuie were delayed so the march did not make progress.  In Kaga, the army was also impeded by the Ikkō-ikki forces, but, on 8/17 of Tenshō 5 (1577), Matsunaga Hisahide and Matsunaga Hisamichi (father and son) of Yamato Province, who had been participating in the siege of the Ishiyama-Hongan Temple, left the front lines on their own accord and launched a rebellion from their base at Shigisan Castle.  As a result, Nobunaga led his main division with the intention of deploying to the Hokuriku region, but efforts to negotiate with Hisahide and ultimately attack him became urgent priorities, so the plans to advance to the Hokuriku were suspended.  Meanwhile, among the Oda army deployed to Kaga, conflict over issues relating to war strategy arose between Shibata Katsuie and Hashiba Hideyoshi.  Hideyoshi then returned to his home province with permission, depressing the morale of the Oda army.  After advancing into Kaga with the momentum of victory, on 9/23, the Uesugi Forces attacked and roundly defeated the Oda army at the Battle of Tedorigawa.

Afterwards, the influence of the Uesugi in Noto Province declined for a while, but, the death of Uesugi Kenshin in the third month of 1578 triggered a succession struggle within the Uesugi family known as the Otate Conflict.  The Uesugi were then confronted by opposition forces in Noto in addition to Oda forces invading Etchū via Hida Province.  As a result, control of Noto reverted to Nobunaga.