The Ōnin War (応仁の乱 Ōnin no Ran) was a civil war that lasted from 1467 to 1477, during the Muromachi period in Japan. Ōnin refers to the Japanese era during which the war was fought. A dispute between Hosokawa Katsumoto and Yamana Sōzen escalated into a nationwide war involving the Ashikaga shogunate and a number of daimyo in many regions of Japan. The war initiated the Sengoku period, "the Warring States Period". This period was a long, drawn-out struggle for domination by individual daimyo, resulting in a mass power-struggle between the various houses to dominate the whole of Japan.