Shiga's largest keyhole mound, in Azuchi, Omihachiman. Omihachiman City dates it to the mid-4th century and says it shows how the Yamato polity of the time came to value the routes through Omi to the eastern provinces and Hokuriku. The Shiga Prefectural Association for Cultural Heritage calls it important in the history of archaeology and noted in 2018 that a replica of its stone chamber was on display at the Azuchi Castle Archaeological Museum.
Finds & research
Three pit-style chambers and two cist coffins. Kiho and two-deity-and-two-beast mirrors, jasper bracelet-stones (hoe-shaped, wheel, and bracelet types), a cylindrical bronze object, iron double-edged and single-edged swords, arrowheads, axes and knives, and haniwa (Kyoto University Museum).
Official status & archaeological view
Official status
National Historic Site "Hyotanyama Kofun" (designated 1957).
Archaeological view
A keyhole mound about 136m long (Omihachiman City heritage plan; Shiga Prefectural Association for Cultural Heritage; the Nabunken site database entry registered by Omihachiman City gives 134m), the largest in Shiga Prefecture, dated to the mid-4th century. A pit-style stone chamber, a split-bamboo-shaped wooden coffin, mirrors, stone objects, weapons, and armor are known.
Field notes
About 25 min on foot from JR Azuchi Station. The mound is walkable, though the chambers are reburied. The Shiga Prefectural Association for Cultural Heritage recommends also visiting the Azuchi Castle Archaeological Museum.