There is a view that the phrase "有棺無槨" in Gishiwajinden, which refers to burial methods in Yamatai, describes earthenware-jar coffins, of which many have been excavated in northern Kyushu.
魏志倭人伝中で邪馬台国の埋葬方法を記述した『有棺無槨』を甕棺と見なす見解に基づき、北九州地方に甕棺が多数出土していること。