A 94m-long keyhole mound on the Shinodayama hills in Uedai-cho, Izumi. Built at the end of the Early Kofun period, it is surrounded by a shield-shaped demarcated area resembling a moat. It is renowned for a pictorial-band deity-and-beast mirror inscribed Keisho 3 (239), recovered from a rear-circle burial facility. It is a National Historic Site.
Finds & research
The three clay-covered burials yielded bronze mirrors, iron weapons, armor, beads, and other grave goods. The Keisho 3-inscribed mirror was found outside the coffin in the central facility and is a pictorial-band same-direction-type deity-and-beast mirror, not a triangular-rimmed mirror. The assemblage is collectively designated an Important Cultural Property.
Official status & archaeological view
Official status
It was designated a National Historic Site in March 2008, and five parcels totaling 1,954 square meters were added on February 17, 2026.
Archaeological view
Excavations in 1950–1951 identified three clay-covered burial facilities (central, eastern, and western) in the rear circle.
Field notes
The match between the Keisho 3 date and the year associated with Himiko's mission to Wei is significant, but that match alone does not identify the occupant or establish how the mirror was transmitted.