Kiyosu Castle

The Starting Point Toward Rule of the Realm—Kiyosu Castle and Oda Nobunaga

Kiyosu Castle (Kiyosujō) is a castle located in Kiyosu City (Kiyosushi), Aichi Prefecture. As the place where Oda Nobunaga, who raised the banner of “tenka fubu,” unified Owari and took his first steps toward the unification of the realm, it counts as one of the most dramatic castles in Japanese history. The present keep is a reinforced-concrete mock keep built in Heisei 1 (1989) on a site adjacent to the ruins of Kiyosu Castle, but the keep crowned with golden shachihoko and the vermilion-lacquered Ōte Bridge reflect beautifully on the flow of the Gojō River, forming a distinctive landscape.

The history of Kiyosu Castle dates back to Ōei 12 (1405), and it is said to have been built in the Muromachi period as a base of the Shiba clan (Shibashi). Afterward it became the residence of the deputy constable (shugo-dai) Oda Yamato-no-kami family, functioning as the political center of Owari Province during the Sengoku period. Nobunaga succeeded his father Nobuhide around Tenbun 20 (1551), and the young Nobunaga, who moved from Nagoya (Nagono) Castle to Kiyosu Castle in Kōji 1 (1555), fought his battles to unify Owari from here as his base.

The Eve of Okehazama—From Kiyosu Castle to the Imagawa Army

Kiyosu Castle became the stage of its most glorious historical moment on the 19th day of the 5th month of Eiroku 3 (1560)—the morning of the Battle of Okehazama. A great army, said to number as many as 25,000, led by Imagawa Yoshimoto, had invaded Owari and was attacking the Oda-side Washizu Fort and Marune Fort. Receiving this news at Kiyosu Castle, Nobunaga sallied out of the castle at the head of a force said to be only 2,000, or even 3,000.

Amid an overwhelming disparity in forces, Nobunaga danced the dance of Atsumori and set out to battle. This “departure from Kiyosu Castle” is one of the most famous departure scenes in Japanese history, and it has been passed down as a crystallization of Nobunaga’s boldness, decisiveness, and willingness to face even death. Kiyosu Castle is etched forever into Japanese history as the stage of this historic moment.

Nobunaga, who succeeded in killing Imagawa Yoshimoto in the surprise attack at Okehazama, used Kiyosu Castle as a foothold to complete the unification of Owari. In Eiroku 6 (1563) he moved his base to Komakiyama Castle, and further in Eiroku 10 (1567) he captured Inabayama Castle (later Gifu Castle) and moved to Gifu. Kiyosu Castle continued to play an important role as the center of Owari, functioning as a rear-support base for Nobunaga’s strategy for unifying the realm.

The Kiyosu Conference—One Night That Decided the Fate of the Realm

Kiyosu Castle returned to center stage of history in the 6th month of Tenshō 10 (1582). Over the succession to Nobunaga’s household—Nobunaga having been killed by Akechi Mitsuhide in the Honnōji Incident on the 2nd day of the 6th month—the four senior retainers (jūshin) Hashiba Hideyoshi, Shibata Katsuie, Niwa Nagahide, and Ikeda Tsuneoki gathered at Kiyosu Castle to deliberate. This “Kiyosu Conference (Kiyosu kaigi)” is one of the most important political conferences in Japanese history, and its conclusion led directly to the establishment of the later Toyotomi regime.

Hideyoshi insisted on installing Sanbōshi (later Oda Hidenobu), the heir of Nobutada, Nobunaga’s eldest son, while Katsuie backed Nobutaka, the third son. In the end Hideyoshi’s position prevailed, and Sanbōshi came to inherit the Oda household headship. Hideyoshi, who emerged as the victor of this conference, went on to defeat Katsuie in the subsequent power struggle (Battle of Shizugatake, Tenshō 11), and began his path toward the unification of the realm. Kiyosu Castle is remembered as the stage of this historical turning point, an indispensable place in the history of the Sengoku period.

Kiyosu and Nagoya Castle—The Tragedy of Castle Dismantling

Kiyosu Castle was effectively abandoned in Keichō 15 (1610) through the “Kiyosu-goshi (Kiyosu relocation)” carried out at the command of Tokugawa Ieyasu. The Kiyosu relocation was a massive construction project that moved the castle and the castle town of Kiyosu, in their entirety, to the site of the Nagoya Castle then being newly built; Kiyosu’s buildings, stone, and residents all moved to Nagoya en masse. As a result of this thorough relocation work, almost no keep or stone walls remained at the former site of Kiyosu Castle, and the surviving remains today are limited.

The history of this “Kiyosu-goshi” vividly shows that a castle is not merely a building but a living community united with the residents of its castle town. When the castle moved, the people moved with it, and culture and economy moved too—the Kiyosu relocation was a historical event that most dramatically demonstrated this dynamism. The present mock keep of Kiyosu Castle stands within Kiyosu Regional Culture Plaza, adjacent to the former castle site, and only part of an earthen rampart remains in one corner of the old site as a relic of the past.

Oda Family Swords—Nobunaga’s Beloved Blades and Sword Culture

Kiyosu Castle, as the base of Oda Nobunaga, is deeply connected with the sword culture of the blades Nobunaga possessed. Nobunaga was a Sengoku daimyō who actively used Japanese swords not only as weapons but also as political and artistic symbols, and his sword collection was regarded as an important proof of the qualities of a ruler of the realm.

Among Nobunaga’s beloved swords, the most famous is the “Yoshimoto Samonji (Yoshimoto Samonji).” It is a famous blade said to have been taken from Imagawa Yoshimoto, whom he slew at the Battle of Okehazama. Samonji is said to be the work of Chikushū Sa (Samonji), a master smith active in Chikuzen Province (present-day Fukuoka Prefecture) in the Nanboku-chō period. Nobunaga had this blade shortened (suriage) and had a gold-inlaid inscription placed on the tang (nakago) recording that he had slain Yoshimoto. This sword is said to have passed from Nobunaga to Hideyoshi and then to the Tokugawa family; it is now held by Kenkun Shrine (Kita Ward, Kyoto City) and is on deposit at the Kyoto National Museum.

Nobunaga also possessed the famous tantō “Yagen Tōshirō (Yagen Tōshirō),” a celebrated short sword by Awataguchi Yoshimitsu. This short sword, presented to Nobunaga by Matsunaga Hisahide in Genki 2 (1571), is said to have been lost in the fire of the Honnōji Incident. As the castle that was the starting point of these tales of Nobunaga’s swords, Kiyosu Castle is also a pilgrimage site of special significance for sword enthusiasts.

Kiyosu Castle and TOUKENZA

Date Masamune of Sendai, where TOUKENZA is based, was a warlord of a generation about 30 years after Nobunaga of the Kiyosu Castle era.

When Nobunaga set out from Kiyosu Castle toward Okehazama with a sword at his waist, that blade must have been a masterpiece by the hand of a master craftsman. Masamune, too, as a warlord who lived in the same era as Nobunaga, belongs to a spiritual lineage that cherished fine swords, fine armor, and fine works of art. Kiyosu Castle, at the center of the Sengoku period when Japanese swords shone as crystallizations of authority and aesthetics, is one of the places that embodies the historical layering of Japanese sword culture conveyed by TOUKENZA.