Osamezuka Kofun is a scallop shell-shaped mounded tomb located near the southeast corner of Nintoku-tenno-ryo Kofun [2-1]. It is considered to be related to Nintoku-tenno-ryo Kofun as a satellite tomb.
The mound has been reconstructed, with a length of 58 m, and the round rear part is 4.2 m high.
Small cylindrical haniwa were arranged on the terraces, and Sue ware (stoneware) and cylindrical haniwa have been unearthed from the moat.
The construction period dates to the first half of the 5th century.