The Onin War, beginning in 1467, helped start Japan’s Sengoku period.
The conflict began in Kyoto during a dispute over succession to the Ashikaga shogunate. Rival military leaders Hosokawa Katsumoto and Yamana Sōzen supported opposing sides, while disagreements among powerful families turned the succession question into a much broader struggle.
Fighting devastated large parts of Kyoto and weakened the authority of the Ashikaga shogunate. The war formally ended in 1477, but its settlement did not restore strong central control. Instead, many regional daimyo gained greater independence, creating the fragmented political landscape associated with the Sengoku period.
The Onin War was not a single clean contest between two unified national armies. Alliances shifted, local disputes multiplied, and warfare spread beyond the original succession issue. The Genpei War belonged to the late 12th century, while the Boshin War occurred during the Meiji Restoration in the 19th century.