However, it isn't known whether they were actually the descendants of the Sudo Yamanouchi clan because the apparent descendants of that clan existed separately in Bigo Province during the Warring States period (this Yamauchi clan later became part of the Mori clan and continued into the Edo period) and a record of even the name of the ascendants of Kazutoyo has not been found for eight generations preceding Katsutoyo's great grandfather.
ただし首藤山内氏の明らかな末裔は戦国時代当時には別に備後国に存在し（この山内氏はその後毛利氏に帰属し、江戸時代まで続いている）ている一方、一豊の山内氏は曽祖父以前から八代分について名前すら伝わっておらず本当に首藤山内氏の末裔であるかどうかは不明である。