When he returned with Itō Hirobumi, he unsuccessfully tried to prevent war (the Battle of Shimonoseki) between Chōshū and the Western naval powers over the closing of the Straits of Shimonoseki to foreign shipping.
Ketika ia kembali dengan Itō Hirobumi, ia gagal mencoba untuk mencegah perang (Pertempuran Shimonoseki) antara Chōshū dan kekuatan angkatan laut barat selama penutupan Selat Shimonoseki ke pelayaran asing.