清洲城

The Starting Point of a Hegemon: Kiyosu Castle and Oda Nobunaga

Kiyosu Castle in Kiyosu City, Aichi Prefecture, is one of Japan's most dramatic castle sites — the place from which Oda Nobunaga launched his campaigns to unify Owari province and, ultimately, to conquer all of Japan under his banner "Tenka Fubu" (Rule the Realm by Force of Arms). The current keep, rebuilt in 1989 at the foot of the Kiyosu Bridge, rises in cinnabar red above the Gojō River, creating a distinctive riverside silhouette.

The castle's history begins around 1457 (Chōroku 1), when it was built as a base for the Shiba clan. It later became the seat of the Oda Yamato-no-kami line, and served as the political center of Owari province through the Sengoku period. Nobunaga succeeded his father Nobuhide in 1551 and used Kiyosu as his base to fight for control of Owari, ultimately unifying the province.

The Eve of Okehazama: From Kiyosu to Victory Against Imagawa

Kiyosu Castle's most luminous historical moment came on the morning of May 19, 1560 — the dawn of the Battle of Okehazama. Imagawa Yoshimoto advanced on Owari with a force variously reported at 25,000 men, capturing the Zenshōji fort and threatening the Washizu and Marune strongpoints. Receiving the news at Kiyosu, Nobunaga rode out with a force of perhaps 2,000 to 3,000 men.

Against these impossible odds, Nobunaga performed the dance of "Atsumori" and led his men out. This "departure from Kiyosu Castle" is one of the most famous military sortie scenes in Japanese history — a crystallization of Nobunaga's decisiveness and his absolute contempt for death. Kiyosu Castle is forever inscribed in Japanese history as the stage of this moment. After his surprise attack killed Yoshimoto, Nobunaga completed Owari's unification and in 1567 moved his base from Kiyosu to Inabayama Castle (later Gifu Castle).

The Kiyosu Council: One Night That Decided the Realm

Kiyosu Castle returned to center stage in June 1582. After Nobunaga's assassination in the Honnōji Incident (June 2), the four major retainers — Hashiba Hideyoshi, Shibata Katsuie, Niwa Nagahide, and Ikeda Tsuneoki — convened at Kiyosu to decide the succession. This "Kiyosu Council" is one of the most important political conferences in Japanese history, and its outcome led directly to the establishment of the Toyotomi regime.

Hideyoshi argued for Nobunaga's infant grandson (the three-year-old Samboshi, later Oda Hidenobu); Katsuie backed Nobunaga's third son Nobutaka. Hideyoshi prevailed, and Samboshi was brought to Kiyosu Castle. Having won the council, Hideyoshi defeated Katsuie at the Battle of Shizugatake (1583) and began his own march toward national supremacy. Kiyosu Castle is indispensable in Japanese Sengoku history as the stage of this turning point.

The Kiyosu Transfer: A Castle's Dissolution

In 1610 (Keichō 15), Tokugawa Ieyasu ordered the "Kiyosu-goshi" (Kiyosu Transfer) — effectively ending the castle's life. The entire castle and castle town of Kiyosu were relocated wholesale to the newly built Nagoya Castle, with buildings, stones, and inhabitants all moved to Nagoya. The result was that almost nothing of the original Kiyosu Castle — no keep, no stone walls — survives today; only a small section of earthworks remains on the original site. The current reconstructed keep stands about 200 meters from the original location.

This history of the Kiyosu Transfer vividly demonstrates that a castle is not merely a building but a living community integrated with its townspeople. When the castle moves, people and culture move with it — the Kiyosu Transfer is the most dramatic historical demonstration of that truth.

The Oda Family's Swords: Nobunaga's Beloved Blades

Kiyosu Castle is deeply connected to Nobunaga's sword culture. Nobunaga actively used the Japanese sword as a political and artistic symbol as well as a weapon, and his sword collection was an important demonstration of his credentials as a ruler.

His most famous blade is "Yoshimoto Samonji" — a tachi said to have been taken from Imagawa Yoshimoto after Okehazama, attributed to the great Nanbokuchō-era smith Samonji of Chikuzen province. Nobunaga treasured it, gave it the name "Yoshimoto Samonji," and the blade passed through Hideyoshi to the Tokugawa family; it is now held by the Kobe City Museum.

Nobunaga also features in famous anecdotes involving the tantō "Yagen Tōshirō" (by Awataguchi Yoshimitsu), where he is said to have attempted (with varying results by different tellings) to use it for tameshigiri — stories that convey both his obsession with fine swords and his forceful personality. Kiyosu Castle, as the starting point of these sword stories, is a pilgrimage site for sword enthusiasts.

Kiyosu Castle and DATEKATANA

Date Masamune of Sendai — DATEKATANA's spiritual home — was a generation younger than Nobunaga's Kiyosu era. Masamune deeply admired Nobunaga; it is famously said he regretted all his life that he was born too late to serve under him. Kiyosu Castle, as the youthful base of the warrior Masamune most admired, carries special meaning for DATEKATANA.

The sword Nobunaga wore when he rode out from Kiyosu toward Okehazama was surely a masterwork by a great smith. Masamune, living within the same warrior tradition, occupied the same spiritual lineage of those who prized fine swords, fine armor, and fine art. Kiyosu Castle — at the center of the Sengoku age when swords shone as crystallizations of authority and aesthetics — is one of the places that embodies the historical depth of sword culture that DATEKATANA exists to convey.