Battle of Ino

The Battle of Ino and Its Meaning — Nobunaga's "First Victory"

On August 24 of Kōji 2 (1556), in Ino, Owari Province (present-day Nishi Ward, Nagoya, Aichi Prefecture), Oda Nobunaga clashed with the forces of his brother Nobuyuki (also known as Nobusuke). This Battle of Ino stands in history as the engagement in which Oda Nobunaga, who would later walk the path to unification of the realm, first demonstrated his true ability as a field commander. The forces were said to number approximately 700 strong under Nobunaga, while the allied army of Nobuyuki, Shibata Katsuie, and Hayashi Michikatsu numbered some 2,000, giving Nobunaga a decisive numerical disadvantage. Yet Nobunaga's martial conduct in repelling this adversity would become the starting point for his later dominion.

The Background of the Conflict — The Struggle for Power in Owari after Father Hideaki's Death

The Battle of Ino arose from the sudden death of Nobunaga's father, Hideaki, in Tenbun 21 (1552). Oda Hideaki was a powerful warlord of Owari, commanding influence centered on the region around Kiyosu Castle. With his death, his eldest son Nobunaga inherited the headship of the clan. However, Nobunaga was known for the eccentric conduct of "the great fool of Owari," and many retainers favored his younger brother Nobuyuki, who was known to be courteous and had received proper education (also called Nobusuke).

Hayashi Hideo served as Nobuyuki's guardian, and veteran general Shibata Katsuie also joined the Nobuyuki faction. Hideo was a senior retainer who had served Hideaki for many years as a member of the council of administrators; by backing Nobuyuki, he sought to preserve his own influence. Thus a factional conflict between the "Nobunaga faction" and the "Nobuyuki faction" deepened within Owari Province.

In Kōji 2 (1556), the conflict between Nobunaga, now lord of Kiyosu Castle, and Nobuyuki, lord of Suemori Castle, finally escalated to armed confrontation. The allied forces of Nobuyuki, Katsuie, and Michikatsu mobilized some 2,000 strong and made a show of attacking Nobunaga's base. In response, Nobunaga chose active engagement, leading approximately 700 cavalry in a counterattack.

The Battle of Ino and the Practical Use of Japanese Swords — The Form of Warfare in Early Sengoku

The year of the Battle of Ino, Kōji 2 (1556), was thirteen years after firearms arrived in Japan (Tenbun 12, 1543). At this point, however, firearms were still in early stages of adoption, and in small-scale engagements such as Ino, the primary weapons remained the bow, spear, and long sword.

During this era, the Mino smiths of the Owari-Mino region were extremely active. The region now called Seki in Gifu Prefecture, known as "Mino Seki," flourished from the late Muromachi period through the Sengoku era as "a great center of practical combat sword production." The characteristic of Mino-tradition blades lay in swords forged by smiths such as Kanemoto (Magoroku), Kanesada (Sasanosuke), and Kanemichi — blades that combined keen cutting ability with durability. Production ranged from mass-market "numerical-quantity" utilitarian swords to special-order blades commissioned by great lords, and these adorned the waists of Sengoku warriors far and wide.

Concerning Nobunaga's own celebrated blades, the later "Heshikiri Hasebe" and "Yakugen Tōjirō" are well known, but these were acquisitions from the Tenshō era (1573–1592). At the time of the Battle of Ino, Nobunaga was still a young warrior of twenty-two, and it is likely he carried a practical sword from Mino or Owari.

Nobunaga's Tactics — Resolute Assault with a Small Elite Force

What Nobunaga demonstrated at the Battle of Ino was aggressive and resolute assault despite overwhelming disadvantage. Against Nobunaga's 700, the Nobuyuki-Katsuie forces numbered over 2,000. By ordinary tactics, Nobunaga should have adopted a defensive stance, yet he seized the initiative and attacked Katsuie's forces head-on. With Nobunaga himself standing at the forefront and charging into the enemy lines, his manner of fighting presaged the innovative tactics that would characterize the Battle of Nagashino of later years.

According to the *Nobunaga-kō ki* (Chronicle of Lord Nobunaga), Nobunaga fought fiercely with a small hand-picked force, and the courage he displayed inspired his retainers to display their full valor. The forces under Katsuie's command, pressed by the momentum of Nobunaga's army, sustained devastating losses; Katsuie himself was wounded and surrendered. Meanwhile, a secondary force led by Hayashi Michikatsu achieved local tactical success by slaying Nobunaga's younger half-brother Nobuhiro, but the overall engagement was decided in Nobunaga's victory.

Shibata Katsuie would later become one of Nobunaga's most trusted generals. The fact that Katsuie, who would contest with Hideyoshi in the Battle of Shizugatake (1583), had fought as Nobunaga's enemy at Ino reveals the complex relationships among Sengoku warlords. While historical records preserve no specific identity of the long sword Katsuie carried at Ino, it is reasonable to suppose that such a veteran general, possessed of strength enough to oppose Nobunaga, would have carried a blade from a master smith of that era.

The Fate of Nobuyuki — The Mother's Plea and the Purge of the Following Year

Following his defeat at Ino, Nobuyuki was spared punishment through the intercession of his mother Tsuchida Gozen (the true mother of both Nobunaga and Nobuyuki). Nobunaga pardoned his brother, but in Kōji 3 (1557), when Nobuyuki attempted rebellion once more, this time Nobunaga showed no mercy and carried out a purge. Nobunaga feigned illness, summoned Nobuyuki to Kiyosu Castle, and cut him down in a single stroke. This "purge by stratagem" is passed down as an episode revealing a glimpse of the ruthless rule Nobunaga would display in later years.

The act of "drawing a sword against one's brother" was a grave decision even in samurai society. The Japanese sword served not only as a weapon on the battlefield, but also as an instrument for such pitiless determinations. Various theories exist regarding the sword Nobunaga used to kill his brother Nobuyuki; however, the "Heshikiri Hasebe" celebrated as one of Nobunaga's prized blades (later passed to Hideyoshi and then to the Kuroda house) dates to the Tenshō era and had not yet come into Nobunaga's possession at the time of Ino. It is likely that a practical sword of Owari or Mino from that era was employed.

Nobunaga's Unification of Owari and Sword Culture — The Formative Period of His Dominion

In the process through which Nobunaga formally unified Owari following the Battle of Ino, he gained control of the economic sphere centered on Nagoya and Kiyosu. This region was also strongly influenced by the sword-forging culture of Mino (Gifu), and practical blades produced by "Mino Seki" were supplied to warriors throughout the region. Mino-tradition smiths such as Kanemoto (Magoroku) and Kanesada (Sasanosuke) were highly active during this era, producing in great quantity "numerical-quantity swords" that emphasized cutting ability and durability suitable for actual combat.

This "mass-production system for Mino blades" proceeded in parallel with Nobunaga's later military reforms (the establishment of armed light-infantry units with firearms). The stable supply of practical swords usable across the ranks from ashigaru foot soldiers to samurai, alongside costly individually commissioned masterwork blades, underpinned the military organization of the Sengoku era. The swords carried by the approximately 700 cavalry of Nobunaga's force at Ino likely consisted largely of such practical blades from Mino and Owari.

The Historical Significance of the Battle of Ino — The Dawn of the Nobunaga Age

In scale, the Battle of Ino was merely a small engagement. Yet its significance is immeasurable. First, it proved to both himself and others that Nobunaga possessed the ability to overcome numerical disadvantage on the battlefield. Second, by eliminating the greatest internal rebellious threat in his brother Nobuyuki, Nobunaga's power base was solidified. Third, the relationships with Shibata Katsuie and Hayashi Michikatsu, who would become Nobunaga's intimate retainers, were paradoxically strengthened through this very battle.

After Ino, Nobunaga took the first step toward the unification of the realm when he defeated Imagawa Yoshimoto at the Battle of Okehazama in Eiroku 3 (1560). One might say that the bold, surprise-attack tactics demonstrated at Okehazama were honed through the experience of victory with a small force at Ino. In the history of the Japanese sword, the blades of the Sengoku era transcended mere weaponry to become symbols of "the samurai's soul and will." Each blade wielded at Ino became part of the genesis of the great historical current that would ultimately lead to the unification of the realm.

Swords and Smiths Associated with the Battle of Ino — The Smithcraft Culture of Owari and Mino in the Tenbun Era

The Tenbun era (1532–1555) occupied a transitional period in Japanese sword history between the late old-sword period, known as "sue-koto" (end-period swords), and the "shin-tō" (new swords). During this era, the smiths of Mino Province (present-day Gifu Prefecture) actively produced what were called "numerical-quantity" practical swords for mass output.

The representative Mino smith is "Seki Magoroku Kanemoto." The first Magoroku Kanemoto was a smith active from the Bunmei era (1469–1487), renowned for blades possessing keen cutting ability and durability suited to actual combat. He possessed a characteristic hamon (blade pattern) called "three-pine-crests," earning high evaluation from warlords. Kanemoto's successors energetically produced blades throughout the Sengoku period, and it is thought they supplied them widely to units composed primarily of ashigaru light infantry, such as those in Nobunaga's forces.

Moreover, "Seki Kanesada (Sasanosuke)" was a smith combining utility with beauty, earning commissions from Sengoku daimyō. He established the lineage that would later become the prototype of the "Izumi-no-kami Kanesada," celebrated as the beloved blade of Hijikata Toshizō. Kanesada's swords were called "supreme in cutting ability," meeting the demand of combat-minded Sengoku warriors.

Furthermore, "Echizen Kanemichi" was a smith who migrated from Mino to Echizen (present-day Fukui Prefecture) and, under the tutelage of Horikawa Kunihiro, laid the foundation for the new-sword tradition. The Kanemichi lineage of Echizen later developed into the Echizen school of smithcraft, leading to the Horikawa tradition.

The blades forged by these smith groups of Mino and Owari were the swords worn at the waists of warriors on both sides of the Battle of Ino. In the study of Japanese swords, knowledge of the place of origin and smith lineage of blades serves as a key to the concrete reconstruction of the lives of the warriors who lived amid the events of history. By viewing Ino — "the origin of Nobunaga" — from the perspective of the Japanese sword, one can touch upon the very essence of samurai culture during the Sengoku era.