The details of this incident are lost, but there is a theory that Yoshimura was the mastermind behind it all, who provoked Kugyo into assassinating Sanemoto, in order to be rid of those two at the same time; Yoshimura's wife was Kugyo's wet nurse, and his son, Mitsumura MIURA, was a disciple in the Kugyo household, suggesting that Yoshimura had close ties with Kugyo, which makes this theory plausible.
この事件の真相は明らかではないが、公暁の乳母は義村の妻であり、子の三浦光村は公暁の門弟であるなど、義村との縁が深い事から、事件は公暁をそそのかして実朝と義時を同時に葬ろうとした義村が黒幕であるとする見方もある。