Dating back to the latter half of the 5th century, this keyhole-shaped burial mound extends 62 meters in length and has been designated as a National Historic Site. The stone chamber of the Eta Funayama Kofun is open for visitors to explore.

The burial mound has yielded over 200 artifacts, including a gold and copper crown, shoes, pure gold earrings, a bit for a horse, stirrups, a tachi (long sword), and a sword, all of which are stored as a collective National Treasure at the Tokyo National Museum. Among these artifacts, a sword engraved with 75 Chinese characters in silver is considered the oldest of its kind in Japan, serving as a precious resource for the study of Japan's ancient history.