The family crest of the head family of the Tokugawa clan (the linage of the Shogun) was Omote Aoi-no-Gomon (the family crest using front sides of three leaves of Hollyhock), in which front sides of Hollyhock leaves were depicted to represent the shogun's title 'Seii Taishogun' (literally, "great general who subdues the barbarians"), while that of the Mito family was Ura Aoi-no-Gomon (the family crest using undersides of three leaves of Hollyhook); therefore, there exists an opinion which holds that officially the Mito family was not recognized as Tokugawa Gosanke.
また、将軍家宗家が「征夷大将軍」と現すために三葉を表にした表葵御紋であるのに対して、水戸家の葵御紋は三葉が裏になった裏葵御紋が正紋であるために、正式には御三家ではない説がある。