The Mozu Tombs (百舌鳥古墳群, Mozu kofungun) are a group of megalithic tombs in Sakai, Osaka Prefecture, Japan. Originally consisting of more than 100 tombs, only less than 50% of the key-hole, round and rectangular tombs remain.The Daisenryo Kofun (大仙陵古墳, Daisenryō kofun), the largest kofun in Japan, are believed to have been constructed over a period of 20 years in the mid 5th century during the Kofun Period.