Kannō Disturbance and the Sword

The Kannō Disturbance (1350–1352) was a power struggle between Ashikaga Takauji and his younger brother Tadayoshi that triggered the largest internal schism of the Nanbokuchō period. Far more than a sibling dispute, this conflict represented a collision between the conservative faction within the Ashikaga shogunate (the Kō Moronao and Moroyasu faction) and the idealist faction (the Tadayoshi faction), exposing the fundamental fragility of the Muromachi system in broad daylight.

From the perspective of sword history, this period coincides precisely with the peak of production of Nanbokuchō ōdachi. The military commanders of the Kannō Disturbance favored imposing long-bladed tachi exceeding three shaku (approximately 90 cm) in cutting edge. The Bizen, Sōshū, and Yamato traditions competed with one another, mass-producing large naginata-form swords that combined martial efficacy with artistic value.

In the Kyoto and Ōmi regions, where Tadayoshi's supporters were concentrated, Yamashiro and Yamato smiths forged substantial shinogi-zukuri tachi to fulfill orders from Tadayoshi's faction. Meanwhile, the military commanders of Kyushu and the Kantō who followed Takauji deepened their ties with Bizen and Sōshū smiths, accelerating the regional diffusion of these traditions. After the disturbance ended—with Tadayoshi dying by poison and Moronao and Moroyasu being slain—this upheaval dispersed swordsmiths across the provinces and established the foundation for regional swordsmithing. This is an inescapable historical fact.

The Kannō Disturbance also serves as an important reference point in sword appraisal. Swords made during this period display transitional characteristics bridging the preceding Shōchū-Genkō style (1324–1332) and the subsequent Enbun peak style (1356–1361). A tendency toward itame-hada mixed with mokume, with the nioiguchi becoming relatively constrained, is recognized by connoisseurs as the distinctive "tightness" characteristic of the Kannō period. While signed pieces from the Kannō period that survive are few in number, research on unsigned but period-attributed examples continues to contribute to the refinement of Nanbokuchō sword scholarship.