The assault team consisted of nine people, Kumakichi TAKECHI who had been a shizoku (a samurai-oriented family) from Kochi Prefecture and worked at Ministry of Foreign Affairs as well as Kikuma TAKECHI, Norio YAMAZAKI, Naokata SHIMAZAKI, Yoshiaki SHIMOMURA, Masahiko IWATA, Yasumichi NAKAYAMA, Shigeki NAKANISHI and 悦弥太 SAWADA.
襲撃者は高知県士族で、もと外務省に出仕していた武市熊吉ほか、武市喜久馬、山崎則雄、島崎直方、下村義明、岩田正彦、中山泰道、中西茂樹、沢田悦弥太の総勢9人。