Seeking bailout for the government which had been facing economic difficulties after the Seinan War, he went on negotiating the recovery of Japan's taxation authority from the western countries in 1879, where he was successful with the United States but finally set back due to Great Britain's opposition.
西南戦争後の政府の財政難から税権回復を目指し、1879年には諸外国との条約改正に臨み、アメリカとの交渉は良好に進むがイギリスの反対などで挫折している。