Built high up with sweeping views of the Akashi Strait, this group of kofun (tumulus) is believed to be the final resting place for chieftains of the Ama, who made their livelihood around the strait. The age of the Sue ware unearthed here suggest they were built in the latter half of the 6th century, and a surviving legend says one is the tomb of Osashi, an Ama man mentioned in the Nihon Shoki (The Chronicles of Japan).