In October 1867, he accelerated the activities to overthrow the shogunate, including the efforts to gain a secret imperial order of anti-shogunate cooperating together with Toshimichi OKUBO and others.
1867年（慶応3年）10月には大久保利通らと共に討幕の密勅の降下にも尽力して倒幕活動を推進した。