Kofun period

　The Tsubai-Otsukayama Tumulus, which was built in Yamashiro-cho, Kizugawa City, in the latter half of the 3rd century, is significantly different from the Shibagahara Tumulus in Joyo City, which was built in the first half of the 3rd century. The difference is that a huge amount of labor was invested in building a huge keyhole-shaped tumulus for a single deceased person, and luxurious grave goods were placed inside it.
　The tumuli of various sizes, including these giant tumuli, are the tombs of rulers (chiefs) and influential people from various regions at the time. Its distribution and trends tell us about the political power relations from the latter half of the 3rd century to the 6th century.