In the article 'Kodaimakki no togoku ni okeru kaihatsuryoshu no ichi' (the Position of kaihatsu-ryoshu [local notables who actually developed the land] in Togoku [the eastern part of Japan, particularly the Kanto region] in the late ancient times) included in "Chibashi no kenkyu" (the Study of the Chiba clan) edited by Minoru NOGUCHI, Koichiro KURODA discusses that MINAMOTO no Yoshitomo was not toryo (head of the clan) at that stage, and that there is evidence that he attempted to capture the territory as a person of the same level.
また、野口実編『千葉氏の研究』に収録されている論文「古代末期の東国における開発領主の位置」において、黒田紘一郎は、源義朝はその段階では棟梁などではなく、同じレベルで領地を奪おうとした形跡があると論じられている。