Eta Funayama Tumulus is a sixty-two-meter long, keyhole-shaped burial mound at the center of the Seibaru Tumuli, a cluster of mounds spread out on a plateau on the left bank of the Kikusui River in Kumamoto Prefecture, Kyushu. It is thought that it was constructed in the late fifth century or early sixth century. In 1873, a set of exquisite burial goods was excavated from the sarcophagus-style stone burial chamber (also called a 'house-style sarcophagus with side opening') in the round portion of the mound.
The burial goods, which are thought to have been placed in the tomb over several successive interments, include swords (one with an inscription inlaid in silver), armor, weapons and other military gear, a gilt-bronze headdress and a pair of gilt-bronze shoes, gold earrings, jewels and other ornaments, six bronze mirrors, horse trappings, and ceramic utensils.
Along with a gold-inlaid inscription on a double-edged sword blade (J. ken) unearthed from the Inariyama Tumulus in Gyôda City, Saitama Prefecture, this silver-inlaid inscription on a single-edged blade (J. tachi) is one of the oldest examples of a textual record written within the Japanese archipelago. According to a widely accepted theory, the partially legible name "Great King Wa . . . ru" refers to the emperor known in later histories as Yûryaku. From the proper names and titles that appear in this inscription, we can learn a great deal about the system of kingship and the relations between imperial court and powerful local lords in the late fifth century, making this sword an extremely precious historical resource.
The gorgeous gold and gilt-bronze ornaments are among a large number of beautiful excavated objects thought to have been imported from the Korean peninsula. From this we can speculate that the individuals buried in this tumulus played an important role in relations between the Japanese archipelago and the Korean peninsula.