While Mutsu was serving as the Minister of Foreign Affairs, he accomplished treaty revisions (abolishment of chigaihoken) with all fifteen nations with which Japan had concluded unequal treaties.
陸奥が外務大臣の時代に、不平等条約を結んでいた15ヶ国すべてとの間で条約改正（治外法権の撤廃）を成し遂げた。