At that time, England was "against the all-out assault of Edo" because they were "a supporter of the domain of Satsuma" and was afraid of trading trouble with Japan, thus, the 'bloodless surrender of Edo Castle' became the fixed plan of the new government.
当時、“薩摩藩の後ろ盾”となっていたイギリスは日本との貿易に支障が出ることを恐れて“江戸総攻撃に反対”していたため、「江戸無血開城」は新政府の既定方針だった。