The siege of Nanao was one of many sieges undertaken by Uesugi Kenshin, an Uesugi clan daimyà  of Japan's Sengoku period. The castle of Nanao, which was under possession by Hatakeyama Haruà Âmaru.
In 1574, Hatakeyama Yoshinori met an untimely death. he was assassinated by retainers Yusa Tsugumitsu and Nukui Kagetaka. Later, Yoshinori was succeeded by his younger brother, Hatakeyama Yoshitaka, but died in 1576. In the end, Yoshitaka's young son, Hatakeyama Haruà Âmaru, was backed as his successor, but the real authority was held by a senior retainer, Chà  Tsugutsura. In order to promote stability in Noto, Kenshin appoint Jà Âjà  Masashige as the next head of the Hatakeyama clan who had earlier been tendered by the Hatakeyama as hostage. The members of the Noto-Hatakeyama clan resented Kenshin intervention in their affairs by making clear an intention for a showdown against Uesugi.
In 1576, Uesugi Kenshin led 20,000 troops to invade Etchu and to capture Nanao Castle. Chà  Tsugutsura, the head of retainers at Nanao Castle, with 2,000 soldiers, committed to defend the castle. But Kenshin did not attack the Nanao castle, but turned his attack toward outlying castles that served as its support to isolate the castle. Nevertheless, Tsugutsura refused to surrender from the stronghold.
In 1577, after Kenshin reduced the outlying fortresses that supported the castle of Nanao, he beginning a second siege. At this time, Tsugutsura called upon all of the residents to engage in a war of resistance. As results, nearly 15,000 soldiers and civilians amassed at the castle.
The castle held out until autumn, by which time Tsugutsura had sent a message to Oda Nobunaga in order to seek his assistance. Before Nobunaga had time to respond, however, the castle fell. This was caused partly by disease among the garrison, which ended up claiming the life of even Hatakeyama Haruà Âmaru himself. Yusa Tsugumitsu killed Chà  Tsugutsura and opened the Castle gates for Kenshin, also contributing heavily to the castle's fall. and resulted in the Hatakeyama of Noto switching allegiance to the Uesugi clan.