Sekigahara and the Osaka Campaign: Swords in the Age of Unification

The Final Great Battle and the Sword

On September 15, Keichō 5 (1600), at Sekigahara in Mino Province (present-day Sekigahara Town, Gifu Prefecture), the Eastern Army led by Tokugawa Ieyasu and the Western Army led by Ishida Mitsunari clashed. This battle, decided in a single day, determined the end of the Sengoku era and the opening of the Edo period. Furthermore, through the Winter and Summer Sieges of Osaka from Keichō 19 (1614) to Keichō 20 (1615), the Toyotomi clan was destroyed, and the complete national unification by the Tokugawa shogunate was accomplished.

These fifteen years (1600–1615) represent an extremely critical transition period in sword history. While the practical demand for swords in Sengoku warfare rapidly disappeared, a sword culture of a peaceful era was about to flourish. It was an age of "the dawn of new swords" when craftsmen began to seek new aesthetics while the techniques of ancient swords were continuously inherited.

Swords of Sekigahara — Swords Used in the Final Great Battle

The swords carried by the daimyo who participated in the Battle of Sekigahara were also the culmination of renowned and practical swords that had been tested through long years of the Sengoku period. Each daimyo supplied and presented swords to their retainers, and diverse swords made by swordsmiths from all regions of the country gathered on the Sekigahara battlefield.

Date Masamune participated in the Battle of Sekigahara as part of the Eastern Army and subsequently prospered the Sendai domain while maintaining relations with the Tokugawa shogunate. Masamune was known as an enthusiast of swords, and many of his collections and gifts have been transmitted to the Sendai domain. Among the swords housed in the Sendai City Museum, which preserves works from the Date family, some are believed to have been acquired and possessed by Masamune around this period.

The Siege of Osaka (1614–1615) holds particular significance as the final great battle of the Sengoku era. Many renowned swords possessed by Toyotomi officers were confiscated after the war and became treasures of the Tokugawa family or various domains. Swords, as "relics" of Sengoku warlords, subsequently acquired special value and narrative significance in sword appreciation culture.

The Great Migration of Swordsmiths — The Geography of Shintō Created by the Postwar Period

With the end of warfare, swordsmiths throughout the nation experienced a significant movement. Swordsmiths who had served various daimyo throughout the Sengoku period moved in search of new patrons in the postwar new order. This "great migration of swordsmiths" determined the geographic distribution of sword-producing areas in the Shintō era.

The most symbolic development was the activity of Horikawa Kunihiro, the greatest master of the Shintō period. Kunihiro was from Obi in Hyūga Province (present-day Miyazaki Prefecture), survived the Sengoku period, and opened a workshop in Kyoto's Horikawa district during the Keichō era. From Kunihiro's school emerged many renowned craftsmen, including Izumi no Kami Kunitoki, Kawachi no Kami Kunisuke, and Dewa no Daijō Kuniji, forming the genealogy of Keichō Shintō.

In Echizen Province (present-day Fukui Prefecture), Yasushige, a native of Shimo-Osaka near Ōmi who was relocated to Echizen by Ieyasu's orders, established his position as "Echizen Yasushige." Yasushige's swords, known by the signature "Aoi Shimo-Osaka," were valued as official swords of the Tokugawa house, elevating Echizen's status as a sword-producing area.

The Date Family and Swords — The Establishment of Sendai Domain's Sword Culture

Throughout and around the Battles of Sekigahara and Osaka, Date Masamune demonstrated deep involvement in sword culture. Masamune was known as a connoisseur of swords, commissioning works from renowned swordsmiths and acquiring swords previously owned by Sengoku warlords. In the Sendai domain, the possession of swords was obligatory from daimyo to upper and lower samurai, and the quality control and distribution of swords formed an important part of domain governance.

Some of the swords commissioned and collected by Masamune are now preserved in the Sendai City Museum, serving as valuable witnesses to the sword culture of this era. The sword culture of the Sendai domain during the Keichō and Genna eras (1596–1624) vividly depicts the history of swords in the northeast during the transition from Sengoku tension to peace.

The Dawn of the Shintō Era — The Pursuit of Aesthetic Value

After the Summer Siege of Osaka (1615), permanent peace came to Japan. When the practical demand for warfare disappeared, the criterion for evaluating swords fundamentally shifted from "performance on the battlefield" to "value as artwork." This marked the beginning of the era known as Keichō Shintō.

Swordsmiths of the Shintō period inherited the techniques of ancient swords while pursuing brighter, more elegant hamon and lustrous jigane. This direction remained consistent throughout the Edo period, and the genealogy of Shintō to Shinshintō opened a new chapter in Japanese sword aesthetics. Sekigahara and the Siege of Osaka were the final great historical occasions for the Japanese sword's complete transformation from "an instrument of war" to "the crystallization of the samurai spirit and beauty."