As the first keyhole-shaped mounds appeared between the beginning and middle of the third century, the most widely believed theory claims that the Yamato Kingdom was established around this time; however, there is also a theory that this was a different kingdom (the pre-Yamato Kingdom) and that the Yamato Kingdom emerged after this.
最初の前方後円墳は3世紀前葉～中葉に出現しているのでヤマト王権の成立をこの時期に求める説が有力だが、この時期はまだヤマト王権に先立つ王権の段階（プレ・ヤマト王権）だったとする見解もある。