古墳

Also known as Kofun

thumb|Daisen Kofun, the largest of all kofun, one of many tumuli in the [[Mozu kofungun, Sakai, Osaka Prefecture (5th century)]] are megalithic tombs or tumuli in Northeast Asia. Kofun were mainly constructed in the Japanese archipelago between the middle of the 3rd century to the early 7th century AD.