* Image is for illustrative purposes only.Iron sword excavated from Inariyama Kofun (gold-inlaid inscribed sword)
稲荷山古墳出土鉄剣（金錯銘鉄剣）
Also known as: Kinsakumei Tekken (gold-inlaid inscribed iron sword); Shingai-mei Tekken (iron sword inscribed with the shingai year)
Description
Discovery Background
The Inariyama Kofun iron sword (Inariyama kofun shutsudo tekken) is an iron sword excavated in 1968 from the rear circular section of the Inariyama Kofun in Gyōda, Saitama Prefecture, through excavation survey. When first unearthed, it was covered in rust. In 1978, during conservation treatment carried out at the Gangōji Institute for Research of Cultural Property in Nara, X-ray transmission imaging revealed gold-inlaid inscriptions on both sides of the blade. The discovery was widely reported in September of that year.
Overview of the Sword
The sword is approximately 73.5 centimeters long. A total of 115 kanji characters are inscribed in gold inlay across the front and back combined. Across the front and back, an eight-generation genealogy leading to Owake-no-omi is recorded. The back records that the family had served generation after generation as head of the jōtōjin (sword-bearing guards) and also gives the name of the great king. The number of 115 characters is large even when compared with examples from East Asia.
Meaning of the Inscription
The inscription contains the year date 'shingai (kanoto-i) year' and the name 'Great King Wakatakeru (Wakatakeru Ōkimi)'. It records that Owake-no-omi served this great king and assisted in governing the realm (in other words, helped with government). The leading view identifies Great King Wakatakeru with Emperor Yūryaku, the 21st emperor recorded in the Nihon Shoki. The shingai year is held to correspond to 471.
Academic Significance
The leading view also reads the inscription on the silver-inlaid inscribed great sword excavated from the Eta Funayama Kofun in Kumamoto Prefecture as naming the same great king. As a first-class written historical source showing that the power of the Yamato kingship reached from Kyushu to the Kanto region in the latter half of the fifth century, it is of extremely great significance for research on ancient Japanese history.
Designation and Current Holding
In 1981 the sword was designated an Important Cultural Property. In 1983 it was designated a National Treasure together with other excavated items. The current owner is the state (Agency for Cultural Affairs). It is stored and displayed in a case filled with nitrogen gas at the Saitama Prefectural Sakitama Historical Museum (Gyōda, Saitama Prefecture).
Legends & Stories
X-ray analysis in 1978 revealed a 115-character gold-inlaid inscription naming "King Wakatakeru" (identified with Emperor Yuryaku), providing landmark documentary evidence of Yamato court authority extending across ancient Japan in the 5th century.