Iron Ring for the Former Hoko-ji Temple Buddha Hall Japan, Momoyama period, 17th century Kyoto National Museum This iron ring served as building material for the warlord Toyotomi Hideyoshi's (1536-98) construction project of the Buddha Hall for Hoko-ji Temple, which was formerly built where the Kyoto National Museum stands today. Such metal rings as this supported large wooden pillars for colossal architectural structures as the former Buddha Hall.