Between the middle of the third century and the late seventh century, a lot of major kofun were constructed in Japan, and at this time in Korea, a lot of kofun which have tumuli were constructed.
日本列島で大規模な古墳が築造された3世紀半ば過ぎから7世紀後半にかけての時期には、朝鮮半島でも墳丘をもつ古墳が盛んに造営された。