Tokugawa Ieyasu ordered the construction of the castle

In order to advance into Owari Province, the military governor of Suruga Province, Imagawa Ujichika, built Yanagi-no-maru, a precursor castle at Nagoya, between 1521 and 1528 during the Taiei era for his son, Imagawa Ujitoyo. It was located near the site of the later Ninomaru residence. Oda Nobuhide seized it from Imagawa Ujitoyo in March 1532 (Kyōroku 5), residing there and changing the name to Nagoya Castle. His son, Oda Nobunaga, was supposedly born there in 1534 (Tenbun 3), although this is subject to debate. After he defeated Oda Nobutomo at Kiyosu Castle in April 1555 (Kōji 1), he established his residence there. Around 1582 (Tenshō 10), the castle at Nagoya was abandoned.

After various upheavals in Japan, Tokugawa Ieyasu emerged victorious and decided in November 1609 (Keichō 14) to rebuild the castle at Nagoya. Up until the Meiji Restoration, Nagoya Castle flourished as the castle where the Owari branch, the foremost of the three Tokugawa clan lineages, resided. Castle construction technology had been extensively developed and consolidated since the construction of Azuchi Castle in 1576 by Oda Nobunaga (1534–1582). One of the main architects who designed and directed the building of the castle was Nakai Masakiyo, who was previously involved in the construction of the Nijō, Fushimi, Edo, and Sunpu castles. He had gathered and refined existing castle and fortification construction technology and techniques and ultimately formulated the standards for the Tokugawa shogunate's castles, as exemplified by Nagoya Castle.

Early restoration and expansion

In January 1610 (Keichō 15), the site was roped off and work began. Tokugawa Ieyasu ordered various daimyō to help with the construction of what was to become the new capital of the existing Owari Province. Katō Kiyomasa, Fukushima Masanori, and Maeda Toshimitsu were among the 20 feudal lords from the northern and western part of Japan who were assigned to assist in the project. The inscriptions of feudal lords and their vassals, carved on the stones they carried, are still visible today. In August 1610 the stone foundation of the main keep (tenshu) was completed, and by December construction of the stone walls for the Honmaru, Ninomaru, Nishinomaru, and Ofukemaru buildings was almost finished. In June 1611 (Keichō 16) a canal that today is the Hori River was built. The source for much of the building material for the new castle was the smaller Kiyosu Castle, including its tenshu, which was rebuilt as the northwest turret. In mid-1612 (Keichō 17), the construction of Honmaru Palace began, and the main keep was completed in December of that year.

Artists including Kanō Sadanobu painted the walls, ceilings, and sliding doors of Honmaru Palace in 1614 (Keichō 19). Construction of the gates and the Sannomaru moat were completed in July, and in November of that year the Shōgun Tokugawa Hidetada came for an inspection. Honmaru Palace was finished in February 1615 (Keichō 20) and Ninomaru Palace in 1617 (Genna 3). The Tōshō-gū shrine was established in the Sannomaru enceinte in 1619 (Genna 5), and the northwest turret, the former Kiyosu Tower of the Ofukemaru, was completed. In 1620 (Genna 6), Tokugawa Yoshinao (1601–1650) moved into Ninomaru Palace, where in 1627 (Kan'ei 4), a sanctuary was also constructed.

Overall renovation began on Honmaru Palace in May 1633 (Kan'ei 10) in preparation of the upcoming visit of Shōgun Tokugawa Iemitsu on his way to the imperial capital at Kyoto. Additional chambers, bathrooms, and halls, such as Jorakuden and Oyudonoshoin, were constructed. Kanō Tan'yū and other artists painted the walls, ceilings, and sliding doors in the new extensions in 1634 (Kan'ei 11). Work was completed in June, just in time for the shōgun's visit in July of that year.

For the next hundred years there was ongoing maintenance and renovation of the existing structures. In 1669 (Kanbun 9), repairs were made to the main keep walls and roofs. In November 1685 (Jōkyō 2), repairs were again made to the main keep roof; in March 1709 (Hōei 6) to the first and second stories of the main keep; in August 1720 (Kyōhō 5) to the chidorihafu gables on the third and fourth levels of the main keep; and in December 1726 (Kyōhō 11) to the third-level roofs, karahafu gables, the fourth-level roofs, and the copper tiles of the fifth-level roofs of the main keep. Repairs were also made to the golden shachi of the main keep, replacing their wooden core. Further work was carried out in August 1728 (Kyōhō 13) on the shingled roof of Honmaru Palace, remodeling it into a lightweight, informal roof. Repairs were made to the second-, third-, and fourth-level roofs of the main keep.

In November 1730 (Kyōhō 15), the golden shachi were recast for the first time and covered in wire mesh. In 1752 (Hōreki 2), the large-scale "Restoration of Hōreki" corrected the tilt of the keep, caused by unequal subsidence of its stone wall, and the roofs from the second level upward were tiled with copper. By 1788 (Tenmei 8), the accumulated debt of the Owari branch since 1767 (Meiwa 4) amounted to 215,000 ryō. As a result, the golden shachi had to be melted down and recast with less gold in 1827 (Bunsei 10). A finer wire mesh covered the shachi to hide the fact that they were less golden. In 1846 (Kōka 3), they were again melted down and recast for a third time.

19th and 20th centuries  Ninomaru Palace with the main keep in the background, photograph taken in the 19th century

Law and order broke down as the Tokugawa Shogunate came to an end. The Aomatsuba Incident took place in February 1868 (Keiō 4) in the Ninomaru Palace, and a stone memorial stele was erected in the 1926. After the end of the Shogunate, the Owari branch decided to submit to the emperor. In 1870 (Meiji 3), Tokugawa Yoshikatsu had parts of the castle demolished and donated the golden shachi to the Imperial Household Department. They were removed from the main keep in April 1871 (Meiji 4), transported by steamship from Atsuta port to Tokyo, and were taken to numerous locations in Japan as a traveling exhibition. The male shachi was displayed at the Yushima Seido Exposition in 1872[1] and the female at the 1873 Vienna World Exposition.

 The two main keeps of the castle and surrounding Honmaru Palace structures, in a photograph taken c. 1880

In May 1872 the 3rd Division of the Tokyo Garrison was stationed at the castle and the Nagoya Detached Garrison and barracks were installed on the castle grounds.[2] The demolition of the castle was put on hold after the German minister to Japan, Max von Brandt, spoke out against it. In December 1879 (Meiji 12), the imperial war minister Yamagata Aritomo decided to have the castle preserved on the advice of Colonel Nakamura Shigeto.

 The southwestern turret and connecting gallery to the main keep before the 1891 earthquake

The 1891 Mino–Owari earthquake in October 1891 (Meiji 24) seriously damaged the southwest and Tamon turrets and other structures. Reconstruction and repair work followed, but not everything was rebuilt. In 1893 (Meiji 26), the castle was transferred to the Imperial Household Ministry and in June its name was changed to "Nagoya Detached Palace" or "Nagoya Imperial Villa" (名古屋離宮, Nagoya Rikyū) when the castle was designated as a formal imperial residence.[3] On May 20, 1906 (Meiji 39), the grounds were opened to the public for one day for the National Railroad Five Thousand Miles Celebration. In March 1910 (Meiji 43), bronze shachi brought from Edo Castle were added to the roofs of the small keep and corner turrets. In February 1911 (Meiji 44), the former Hasuike Gate of Edo Castle was transported and reconstructed on the remains of the Nishinomaru-Enoki Gate, which today is used as the main visitors gate. In 1923 (Taishō 12), the southwest turret was repaired.

On December 11, 1930 (Shōwa 5), ownership of the castle was transferred from the Imperial Household Ministry to the City of Nagoya, thus abolishing its status as an imperial villa. In the same month, 24 structures on the castle grounds were designated as national treasures. On February 11, 1931 (Shōwa 6), the grounds were opened to the general public. The next decade saw conservation and archaeological activities and the castle was scientifically documented. In May 1932 (Shōwa 7), a field survey and measurement of the castle were carried out. In July of that year, the old Kayanoki (Japanese nutmeg) tree in the Nishinomaru was designated as a national monument. In December the castle was designated a historical site. In 1936 (Shōwa 11), the Sarumen Tea House (猿面) in the Ninomaru was designated as a national treasure. In June 1942 (Shōwa 17), some of the Honmaru Palace paintings were designated as national treasures. Most of the sliding doors and paintings were put into storage as the Pacific War threatened the Japanese mainland.

 Pacific War bombing by the U.S. Army Air Forces destroyed Nagoya Castle in 1945

During the Pacific War the castle was used as the Tokai district army headquarters and the administration office of the Nagoya POW camp.[4] The aerial bombardments of Nagoya by the United States Army Air Forces as part of the air raids on Japan brought the most destruction to the castle in its entire history. In January 1945 (Shōwa 20), the Sarumen Tea House was destroyed in air raids. On May 14, the main keep, small keep, golden shachi, Honmaru Palace, northeast turret, and other buildings were completely destroyed in air raids. In June of that year, some of the paintings saved from Honmaru Palace were moved for safekeeping to the Haiho Shrine, Toyota-shi. They returned in May 1946 (Shōwa 21).

The castle's surviving former national treasures, which included the southwest, southeast, and northwest turrets, the Omote-Ninomon Gate, and some of the Honmaru Palace paintings were redesignated as Important Cultural Assets by the national government. In 1953 the southeast turret was dismantled for repairs. The Ninomaru Garden was designated a place of scenic beauty. In June 1955 (Shōwa 30), most of the Honmaru Palace paintings—and exactly a year later, the ceiling panel paintings—were designated national important culture assets. In 1957 (Shōwa 32), reconstruction of the castle keeps was started. Second-generation golden shachi were cast in the Osaka Mint and transported to the castle. On October 3, 1959, reconstruction of the two keeps was completed, and the buildings were opened to the public. The next few decades saw further renovation work. In March 1964 (Shōwa 39), the northwest turret was dismantled for repairs. In 1967 (Shōwa 42), the Ninomon of the western iron gate was dismantled for repairs. In 1972 (Shōwa 47), the stone walls at the west side of the East Iron Gate of the Ninomaru were dismantled. The wooden Ninomon was dismantled and later rebuilt at the east Ninomon Gate of the Honmaru.

 Restored Jōdan-no-ma (上段之間) in the Jōraku-den (上洛殿) of the Honmaru Palace (2018)21st century and future plans

In preparation for Expo 2005, English-language plaques were added to most displays, and a 3D movie showing the paintings in Honmaru Palace (本丸御殿, Honmaru Goten) was created for the anticipated large number of visitors. Reconstruction work of the destroyed Honmaru Palace began in 2009 and was completed by 2018.[5] Nagoya mayor Takashi Kawamura announced plans in 2009 to completely reconstruct in wood the main towers that were destroyed during the Pacific War, just as in the original structure. The budget to reconstruct the main towers was estimated at billions of yen.[6][7] After negotiations with the national authorities, the plan was approved and in July 2017 the city officially launched the fundraising campaign. The platform for international online donations opened in 2020.[8] The goal is to reconstruct the main tower by 2022.[9][10][11] Collection of necessary hinoki timber started in the forests of Gifu prefecture in 2019.[12]

The city has plans to further restore Honmaru and Ninomaru structures where photographic evidence and architectural drawings exist such as various turrets, gates and defensive walls. This would also entail moving out existing modern structures on the grounds.[13]