Early Onin ten zogan tsuba, mid Muromachi. The Ōnin War (応仁の乱 Ōnin no Ran) was a civil war that lasted 10 years (1467–1477) during the Muromachi period in Japan. Iron core decorated with small brass “nail heads” and wires on a thin iron plate. Diameter: 90 mm. Thickness: 2 mm.