For example, in "Eimeiroku" written by Kai SHIMADA, he is referred to as the son of Mataemon SERIZAWA and is said to come from a branch family, but there are no corresponding words in the description for the house of Mataemon SERIZAWA in "Suifukeisan" which covers the lineage of Mito Clan warriors.
たとえば島田魁の『英名録』には「芹沢又右衛門子」とあり、分家の出身ともいわれるが、水戸藩士の系譜を網羅する『水府系纂』に記載される芹沢又右衛門家の記述に該当する文言は見当たらない。