Yoshinobu anticipated a secret order to Saccho (Satsuma and Choshu -han Clans) from the Emperor to destroy the Shogunate, and on Oct. 14, 1867, he (as a preemptive measure) suggested to the Imperial Court that he would return his political power to the Emperor; his request was accepted by the Emperor on the 15th, the following day (Taisei Hokan).
薩長へ「討幕の密勅」が下ることを予期した慶喜は（先手を打って）慶応3年（1867年）10月14日、朝廷に対して政権返上を上奏し翌15日勅許された（大政奉還）。