A bitter family feud nearly destroyed Japan's early Ashikaga shogunate in the 1350s.
The Kannō disturbance was not just a sibling rivalry; it was a structural collapse. When Ashikaga Takauji and his brother Tadayoshi turned against each other, they split the government in two, paralyzed the administration, and inadvertently handed their enemies the perfect opportunity to tear the new regime apart from within.
The Kannō disturbance, named after the 1350–1351 era, emerged from a fundamental administrative fracture within the early Ashikaga shogunate. While Ashikaga Takauji held the title of shōgun, his brother Tadayoshi effectively governed the country for over a decade. This bifurcated system meant the regime operated under two separate heads of state, each controlling different bureaucratic organs. Takauji, as the leader of house vassals, directed the Board of Retainers and the Office of Rewards, while Tadayoshi oversaw the judicial functions of the Board of Inquiry and the Board of Coadjutors.
Tensions escalated into open conflict over the regime's future. Takauji acted as an innovator, rewarding battlefield heroics with shugo posts and dividing shōen estates to satisfy his vassals. Tadayoshi, acting as a conservative, fiercely opposed these policies, drafting the Kemmu Formulary to protect traditional estate systems and judicial standards. The rivalry intensified when Takauji appointed Kō no Moronao as his deputy, a man Tadayoshi despised. After failed assassination attempts, Tadayoshi was forced into monastic life in 1349, only to rebel in 1350 by joining the Southern Court, the shogunate's primary enemy.
The civil war that followed devastated the regime's stability. Both brothers cynically used the Southern Court to legitimize their attacks on one another. Tadayoshi achieved early military success, capturing Kyoto and executing the Kō brothers in 1351, but his fortunes reversed after a defeat at Sattayama. Following a brief, insincere reconciliation, Tadayoshi fled to Kamakura, where he died in March 1352—reportedly by poisoning. The chaos allowed renegades and defectors to bolster the Southern Court’s offensive, including figures like Yamana Tokiuji and Ashikaga Tadafuyu. Ultimately, the disturbance ended with power consolidated solely in Takauji’s hands, which, while strengthening the shogunate's central authority, left the regime deeply scarred by the internal betrayal.
Source: Kannō disturbance
