The Kannō Disturbance (1350–1352) and Japanese Swords: How the Early Nanbokucho Civil War Shaped Blade Culture

What was the Kanō Disturbance? — An Overview of Complex Power Struggles

Within the Nanboku-chō period (1336–1392), the Kanō Disturbance (kanō no jōran, 1350–1352) was an especially complex political upheaval. Internal conflict within the Ashikaga Shogunate between Shogun Ashikaga Takauji and his younger brother Ashikaga Tadayoshi intensified, further complicated by the involvement of Kō no Moronao and other close associates. This created a multifaceted civil war where internal shogunal strife overlapped with the struggle between the Southern and Northern Courts.

After three years of turmoil, the disturbance reached a temporary resolution with Tadayoshi's death in February 1352, but the conflict between the Southern and Northern Courts continued, and nationwide warfare persisted for more than half a century.

Warfare in the Nanboku-chō Period and the Explosion in Sword Demand

The mid-14th century, when the Kanō Disturbance occurred, was a particularly unique phase in Japanese sword history—known as the "age of the ōdachi and nata."

The Nanboku-chō period witnessed dramatic changes in warfare tactics compared to the Kamakura period. Combat shifted from small-scale elite cavalry engagements to infantry-centered group battles and prolonged sieges. With this transition came significant changes in the requirements placed on swords and blades.

Demand for Long Blades: Magnificent ōdachi (blade length 90–120 cm or more) were produced in large quantities, used by mounted warriors to strike from horseback and as votive offerings to temples and shrines. The fact that many ōdachi with recorded makers from the Nanboku-chō period bear dates around the Kanō era attests to the high demand of this period.

Demands for Thick, Robust Blades: There was increasing emphasis on durability in actual combat, and blades suited for armor-piercing (yoroi dōshi) required sturdy, direct construction. In contrast to the thin, elegant tachi of the Kamakura period, rugged, practical swords dominated production.

Master Smiths and Blade-Making Centers Active During the Kanō Disturbance

The Rise of the Bizen Osafune School

The most important sword-producing center throughout the Nanboku-chō period was Bizen (present-day Okayama Prefecture), particularly the Osafune smith collective. During the Kanō Disturbance, the leading smiths of the Osafune school remained highly productive, with the following figures being especially renowned.

Nagayoshi (長義): A representative Osafune master of the Nanboku-chō period who produced numerous magnificent ōdachi. Several of his extant works are designated as Important Cultural Properties or National Treasures.

Kanemitsu (兼光): Reportedly the father of Nagayoshi, active from the Gennō and Jōwa eras through Kanō. He is highly regarded as one of the perfectors of the Nanboku-chō style.

Motoshige (元重): A smith with recorded works bearing Kanō-era dates. He left typical examples of the Nanboku-chō style with bold kissaki at the tang.

Expanding Influence of the Sōshū Tradition

Master smiths of the Sōshū tradition from Sagami (Kanagawa) also played an important role during the Kanō Disturbance. Disciples of Masamune dispersed to various regions to transmit their techniques, and warlords within the territories of both Takauji and Tadayoshi sought Sōshū tradition blades.

Hiromitsu (廣光) and Akihiro (秋廣) were active during the Kanō and Shōhei eras, and are renowned as master smiths who perfected the vigorous nie and intricate hamon characteristic of the Sōshū tradition.

Ashikaga Takauji and Tadayoshi — Sword Connoisseurship and the Disturbance

Ashikaga Takauji was known as a sword enthusiast who patronized skilled smiths. Tadayoshi, for his part, was equally devoted to administrative and cultural endeavors, serving as a patron of sword culture in the tradition of the Kamakura shogunate.

Their conflict was not merely a power struggle but also an ideological dispute over shogunal governance policy—Takauji favoring a martial approach while Tadayoshi advocated civil administration. Though this conflict's direct impact on sword culture is difficult to trace, the division of powerful warlords and daimyo between the two camps meant that smiths in each region responded to the weapon demands of their respective backers.

Impact on Sword Culture Following the Disturbance

The Kanō Disturbance had several direct effects on sword culture.

Smith Migration and Technology Transmission: The civil war prompted many smiths to relocate their bases. The movement of smiths from major centers like Bizen, Yamashiro, and Sōshū to local daimyo increased, facilitating the establishment and development of blade-making techniques in regional production centers.

Increase in Dated Signed Blades: Amid the turmoil of the Nanboku-chō period, which court's era name a smith used became a political statement. Extant signed blades bearing both Kanō (Northern Court era) and Shōhei (Southern Court era) dates survive, illustrating the political complexity of the time.

Establishment of the Nanboku-chō Style in Sword Aesthetics: The Kanō Disturbance period was when the Nanboku-chō style of swordcraft—characterized by magnificent proportions, bold kissaki, and intricate hamon—reached its most refined form. This style continued to be highly valued in later periods as "Nanboku-chō pieces."

Conclusion

The Kanō Disturbance, though an unavoidable complex political upheaval when discussing the Nanboku-chō period, coincides with the golden age of Nanboku-chō-style sword production in the history of Japanese blades. The establishment of mass production regimens centered on Bizen smiths under the Osafune school, the expanding influence of the Sōshū tradition, and the dissemination of techniques throughout the regions all advanced during this period, forming the foundation for the sword culture of the subsequent Muromachi and Sengoku periods.