Dissatisfied with him, extremists in the Satsuma domain such as Shinshichi ARIMA conspired with devoted members of the royalist faction such as Izumi MAGI and Kawachinosuke TANAKA to carry out a raid on the residences of the chief adviser to the Emperor, Hisatada KUJO, and the Kyoto-shoshidai (commissioner dealing with police and judicial affairs in Kyoto), Tadaaki SAKAI (also the lord of the Obama domain in Wakasa Province), and they gathered at the Teradaya, an inn for sailors in Fushimi.
このことに不満を持った薩摩藩の過激派、有馬新七らは同じく薩摩藩の尊王派の志士、真木和泉・田中河内介らと共謀して関白九条尚忠・京都所司代酒井忠義(若狭国小浜藩主)邸を襲撃することを決定し、伏見の船宿寺田屋に集まった。