A keyhole-shaped mound on the Nagaoyama hills in Yamatedai Higashi 1-chome, Takarazuka City, Hyogo Prefecture. Discovered in a 1957 distribution survey, it was excavated from 2007 by the Osaka University Archaeology Laboratory with the cooperation of the Takarazuka City Board of Education, which established that the mound—previously presumed to be square-fronted and square-backed—is in fact keyhole-shaped. It was designated a Takarazuka City Historic Site in 2010.
Finds & research
Stone facing and rows of haniwa have been identified, and the clay-encased coffin chamber in the rear section is reported to be in excellent condition. Details of grave goods are not given in the published materials consulted.
Archaeological view
According to the joint site-tour handouts of Takarazuka City and the Osaka University Archaeology Laboratory, it is a keyhole mound about 42m long (the Comprehensive Database of Archaeological Site Reports gives 40m, with the rear circular section 25m in diameter), with both the front and rear sections built in two tiers and faced with stone, encircled by rows of haniwa. A massive clay-encased wooden coffin (6.7m long, 2.7m wide) was built within a rounded-rectangular burial pit (8.9m by 5.0m) in the rear section, reported to be in good condition. Based on the characteristics of excavated haniwa, it is dated to the early part of the Early Kofun period (early 4th century) and is considered the oldest keyhole mound in the Ina River basin. Before excavation it had been presumed to be a square-fronted, square-backed mound.
Field notes
The Takarazuka City Board of Education and the Osaka University Archaeology Laboratory have jointly conducted excavations since 2007 (a Grants-in-Aid for Scientific Research project led by Shinya Fukunaga). The mound lies near Yamatedai Minami Park, with a walking path nearby.