Kiyosu Castle was initially constructed around 1405 by Shiba Yoshishige, the Governor of Owari, serving as a major strategic defense and later as the seat of power for the Owari region (now Aichi Prefecture). One branch of the Oda clan, administrators of Owari, took control of southern Owari and Kiyosu Castle from 1476, while the other branch was based in Iwakura Castle, overseeing northern Owari.
Kiyosu Castle was the launch point for many significant samurai battles during the turbulent Sengoku, or Warring States Period (1450-1615), including the battles of Okehazama (1560), Anegawa (1570), Nagashino (1575), and Sekigahara (1600).
In 1555, after the death of his father, Oda Nobunaga enlisted the help of his uncle, Oda Nobumitsu, to attack and kill Oda Nobutomo, the clan leader at Kiyosu Castle. Nobunaga subsequently relocated from Nagoya Castle to Kiyosu. Two years later, he discovered a plot by his younger brother, Nobuyuki, to overthrow him. Feigning illness, Nobunaga drew Nobuyuki close and assassinated him within Kiyosu Castle, thereby eliminating opposition and ensuring clan stability.
Kiyosu remained Nobunaga’s base for many years, during which time the city flourished due to his economic reforms and enhanced security. The castle grounds once spanned 1.6 kilometers east-west and 2.8 kilometers north-south, featuring an outer, central, and inner moat system.
On July 16, 1582, just weeks after Nobunaga’s death at Honno-ji Temple in Kyoto, an important meeting regarding the Oda clan’s succession, known as the Kiyosu Conference, was held at Kiyosu Castle. Top Oda retainers, including Shibata Katsuie, Toyotomi Hideyoshi, Niwa Nagahide, and Ikeda Tsuneoki, gathered to decide on Nobunaga’s successor. With Nobunaga’s designated heir, Nobutada, having died at Nijo Castle, the succession was contested between Toyotomi Hideyoshi, who supported Oda Samboshi (Nobunaga’s infant grandson), and Shibata Katsuie, who backed Nobunaga’s third son, Nobutaka. The conference ended without resolution, leading to escalating tensions between Hideyoshi and Katsuie, culminating in the Battle of Shizugatake. Ultimately, Hideyoshi triumphed, leading to Katsuie’s defeat and suicide, and Hideyoshi's eventual domination of Japan.
Following the Battle of Sekigahara in 1600, Kiyosu Castle saw various masters. It was reconstructed in concrete in 1989 across a small river from its original location. The actual site of the keep now features the "Kiyosu Furusato no Yakata," a small rest area and souvenir stall. Surprisingly, the JR train lines and Bullet Train lines run directly through the old castle site. The southern half of Kiyosu Castle is now a park with statues of Oda Nobunaga in full armor and his wife, Princess No-Hime.
The current reconstructed Kiyosu Castle serves as a symbol of Kiyosu City and houses a well-planned museum featuring fascinating displays and artifacts related to the castle’s history and its role in the Period of Warring States.
See also
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Unknown 1585 Letter Reveals How Toyotomi Hideyoshi Gave Yamato to His Brother and Consolidated Power in Japan
A previously unknown letter from Toyotomi Hideyoshi, one of Japan's great unifiers, has been publicly displayed for the first time. Written in 1585, the document reveals how Hideyoshi granted Yamato Province to his younger brother, Hidenaga, and attempted to resolve complicated questions of loyalty among local samurai families.
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The 16-Year-Old Samurai Who Crossed the Pacific and Discovered America in 1860
A new historical exhibition in Japan tells the remarkable story of a teenage samurai who crossed the Pacific Ocean aboard the Kanrin Maru at just sixteen years old. His surviving travel writings offer a rare opportunity to experience America in 1860 through the eyes of a young Japanese traveler who witnessed one of the most important diplomatic journeys of his time.
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Arato Castle
Arato Castle was built in 1524 by the Yamada clan under the orders of their overlord, Murakami, as a small mountain fort. Over time, it gained strategic importance and became a focal point in the conflict between two famous daimyō of the Sengoku period — Takeda Shingen and Murakami Yoshikiyo. This conflict turned the castle into one of the key fortifications in the struggle for control over Shinano Province.
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Tatsuno Castle
Tatsuno Castle is not a single fortification but rather a complex consisting of two parts: a mountain fortress located at the summit of Mount Keirozan and a flatland-mountain castle situated at its base. The mountain stronghold was built around 1499 by Akamatsu Murahide. During the Muromachi period, the Akamatsu clan was an influential family that, at the height of its power, controlled the provinces of Settsu, Harima, Bizen, and Mimasaka. Murahide’s ancestors were directly involved in the events of the Genkō War in the 14th century and in the subsequent establishment of the Ashikaga shogunate. However, by the 15th century, due to the process of gekokujō, the clan began to lose its position under pressure from rising families, including their former vassals—the Urakami and Bessho clans. In addition, the Akamatsu faced constant pressure from the Amago clan of Izumo Province.
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Takamatsu Castle
Takamatsu Castle was founded by Ikoma Chikamasa (1526–1603), who was appointed ruler of Takamatsu by Toyotomi Hideyoshi in 1587. The following year, Chikamasa began construction of the castle on the coast of the Inland Sea (Setonaikai), completing it by 1590.
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Sawayama Castle
During the Kamakura period, Sabo Tokitsuna, the sixth son of Sasaki Sadatsuna, built a fort on Mount Sawayama. This fort occupied a strategically important position because it allowed control over traffic along the important Tōsandō route, which was later known as Nakasendō. This road connected the capital, Kyoto, with the eastern regions of the country. Due to its location, the fortification held great military importance, and during periods of civil war it repeatedly became the site of fierce battles.
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Nadzima Castle
It is believed that the first structures on this site were built by Tachibana Akitoshi (?-1568), head of the Tachibana clan, a branch family of the Ōtomo clan, as auxiliary fortifications for Tachibanayama Castle. In 1587, Toyotomi Hideyoshi established control over the island of Kyushu and granted Chikuzen Province to Kobayakawa Takakage, one of the leading vassals of the Mori clan. Takakage began construction of a new castle on the site of the existing fortifications in 1588. The exact date of completion is unknown, but by the time the invasion of Korea began in 1592, the castle had already been finished, as records note that Toyotomi Hideyoshi stayed there overnight on his way to Hizen Nagoya Castle, which served as the headquarters of the invasion forces.
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Kubota Castle
The founder of the castle is considered to be Satake Yoshinobu (1570–1633). Yoshinobu was one of the six great generals of Toyotomi Hideyoshi. During the Odawara Campaign of 1590, he took part in the siege of Oshi Castle under the command of Ishida Mitsunari, with whom Yoshinobu developed a good relationship.
