Since there were different writing expressions used for one person in historical books, we can also consider that there were possible historical materials which existed to support the origins of the family tree chart for the Emperor Keitai, other than the 'Joguki' (For example, family tree charts of "Nihonshoki" [Chronicles of Japan]).
このような異表記が見られるということは、かつては「上宮記」以外にも継体の出自系譜を伝える史料が存在した可能性（例えば『日本書紀』の系図）を示唆している。