This scandal occurred because of a long-standing grudge that Kakutaro held against Tadayuki, who was a younger brother of Kakutaro's father (Tadatsugu), as a result of Tadatsugu not being allowed to take over as head of the family due to his poor health, despite Tadatsugu and Tadayuki having both been born out of wedlock, and later dying of illness; this led to Kakutaro suffering economic hardships and his younger brother Kenjiro, who was not granted a peerage, going to war in Taiwan as a private soldier where he later died.
この事件は、格太郎の父忠告が忠敬の兄であり共に庶子でありながら病弱を理由として家督相続されず病没、そして金銭に困窮し、また弟賢次郎が華族待遇を受けられず軍夫として台湾に出兵し戦死したことによる度重なる恨みの末の犯行であった。