Ri-chiu's age at death — sixty-four — is the first of several increasingly plausible regnal lifespans in the chronicle. The figures up through Ōjin had carried the legendary inflation of Methuselah-scale years; from Ri-chiu forward, the numbers drop into ranges that a modern reader recognizes as humanly possible. His mausoleum at Mozu is one of the Mozu Tomb Cluster keyhole-shaped kofun, registered as a UNESCO World Heritage site since 2019 along with the rest of the Mozu-Furuichi tumulus group. The cluster includes Emperor Nin-toku's mausoleum (the largest tomb on Earth by footprint, 486 meters long) and contains the largest concentration of fifth-century elite burials in Japan. The Imperial Household Agency continues to restrict excavation of these tombs, so the precise identifications are unverified, but the cluster's existence and scale are well documented.Kojiki CXXXV (Ri-chiu's Burial)