The 오닌 전쟁, or the Onin War, was a civil war in Japan that lasted from 1467 to 1477. It marked the beginning of the Sengoku period, a time of social upheaval and military conflict. The war primarily involved the Ashikaga shogunate and rival factions, leading to widespread destruction in the capital, Kyoto. The conflict arose from a power struggle between two powerful clans, the Hosokawa and the Yamana. Their rivalry escalated into a full-scale war, resulting in the breakdown of central authority and the rise of local warlords, known as daimyōs. The Onin War significantly altered the political landscape of Japan.