Battle of Sekigahara

The Battle of Sekigahara is called Japan's greatest field battle and the decisive contest for national supremacy. On September 15, Keicho 5 (October 21, 1600, in the Gregorian calendar), in Sekigahara, Fuhaku District, Mino Province (present-day Sekigahara Town, Gifu Prefecture), the Eastern Army led by Tokugawa Ieyasu clashed fiercely with the Western Army led by Ishida Mitsunari.

Background and Rising Tensions

In 1598 (Keicho 3), the supreme ruler Toyotomi Hideyoshi died of illness at the age of 62. His successor, Hideyori, was still a child, and state affairs were entrusted to a council of the Five Great Elders and Five Commissioners. However, Tokugawa Ieyasu, the foremost of the Five Great Elders, soon began to violate the order of the Toyotomi house. Unauthorized marriages between daimyo contrary to Hideyoshi's dying wishes and the poaching of retainers—Ieyasu's arbitrary actions were clear. Enraged by this, Ishida Mitsunari, the central figure among the Commissioners, raised the banner of Ieyasu's overthrow and formed the Western Army with Mōri Terumoto as supreme commander. For his part, Ieyasu also rallied the great lords of the eastern provinces, and warfare was joined.

Sword Culture Before the Battle and Its Significance

Swords of this era were not merely weapons but also symbols of military power and authority. One of the swords most cherished by Ieyasu was the "Sohayanotsurugi." This tachi, now housed at Kunozan Tōshōgū in Shizuoka, was Ieyasu's personal blade of defense that he never parted with in life and served as his spiritual support even on the battlefield. The sword deeply associated with Ishida Mitsunari's name is the "Ishida Masamune." After Sekigahara, this blade was presented by Mitsunari to Yuki Hideyas and descended to the Echizen Matsudaira and Tsuyama Matsudaira houses. It is also called the "Kirikomi Masamune" from the slash marks on its blade (now housed in the Tokyo National Museum).

Around the time of Sekigahara, swordsmiths throughout the land were inevitably swept up in the wave of the times. Mino (present-day Gifu Prefecture) was one of the foremost sword-forging centers of the era, with many swordsmiths continuing their craft at close proximity to Sekigahara itself. Mino-tradition swords were known for sturdy construction emphasizing practicality and were widely favored by commanders of both armies as real-combat blades suited to the chaotic age. The view persists that most swords used at Sekigahara were of Mino lineage.

The Course of Battle

In the early morning of September 15, both armies were deployed in the mist-shrouded basin of Sekigahara. The Western Army left their supreme commander Mōri Terumoto at Osaka Castle while Ukita Hideie, Ōtani Yoshitsugu, Shimazu Yoshihiro, and others took positions on the front line. The Eastern Army, centered on Ieyasu's main camp, was flanked by commanders such as Fukushima Masanori, Kuroda Nagamasa, and Hosokawa Tadaoki.

The battle began with fierce attacks by the Western Army, but in the afternoon, the tide turned. Kobayakawa Hideaki, anticipated as a major force for the Western Army, suddenly launched an attack on Ōtani Yoshitsugu's unit from Matsuo Hill. Whether this betrayal resulted from Ieyasu's prior stratagem or from Hideaki's own judgment is debated, but its effect was decisive. The Ōtani Yoshitsugu contingent, despite valiant fighting, was annihilated, and upon this signal, the Western Army's commanders defected one by one to the Eastern Army or withdrew from the field. The battle ended in little more than six hours, and the Western Army suffered a catastrophic defeat.

Swords Speak to the Aftermath

After the battle, Ieyasu distributed rewards to merit, granting the Eastern Army's commanders substantial increases in territory. In this process, numerous celebrated blades moved as gifts. The practice of presenting swords as rewards to the victors had continued throughout the Sengoku period, and Sekigahara became a large-scale occasion for the transfer of renowned swords.

Among the defeated, some left dramatic episodes concerning swords. Hosokawa Gracia, wife of Hosokawa Tadaoki who sided with the Eastern Army, lost her life amid the upheaval, and the "Kasen Kanesada" that Tadaoki possessed came to be remembered as a blade that witnessed that tragedy. Ishida Mitsunari, effective supreme commander of the Western Army, was captured and executed, and swords associated with Mitsunari were confiscated and distributed among Tokugawa and his vassals, treasured as "spoils of war" throughout the Edo period.

The Turning Point in the Contest for Supremacy and the Transformation of Sword Culture

The Battle of Sekigahara brought a major turning point to Japanese sword culture. Thereafter, as Tokugawa's stable and peaceful era continued, swords shifted in emphasis from practical weapons to art objects and spiritual symbols. The transition from the Sengoku era's "kazuuchi-mono" (mass-produced swords) to the Edo era's Shinto culture was accelerated precisely at the boundary of Sekigahara. From Keicho onward, swordsmiths, even as they lost opportunities for martial testing, developed new sword culture centered on polishing, finishing, and connoisseurship.

After achieving national unification, Tokugawa Ieyasu continued to take keen interest in sword management. The foundations of the connoisseurship culture that led to the compilation of the "Kyōho Meibotsu-chō" were nurtured in parallel with the establishment of order following Sekigahara. The sword arts that blossomed under the Bakufu's peace followed a uniquely Japanese cultural trajectory whereby blades from the battlefield were directly elevated to works of art.

Sekigahara remains today in Gifu Prefecture as a battlefield site where visitors can trace the positions of each commander's encampment. For sword enthusiasts, it is also a sacred site where one can sense the final great battle of the Sengoku period firsthand and contemplate the feelings of the commanders assembled there toward their swords.