However, the document of Yoshi's kinship, which was submitted to the bakafu (feudal government) prior to his seppuku states '1. His foster father and real grandfather, Kuranosuke OISHI, died of illness on New Year's Day 28 years ago, 1. His real father, Gennai OISHI, died of illness in September 31 years ago', which reduces the credibility of the adopted child theory.
しかし良雄が切腹前に幕府に出した親類書には、「一、養父・実祖父　二十八年以前正月病死大石内蔵助　一、実父三十一年前九月病死大石権内」となっていることから、養子説の信憑性は低い。