When the coup of August 18 led by Imperial prince Nakagawa no miya Asahiko, the Aizu domain, and the Satsuma domain occurred for the purpose of removing the Choshu domain from the politics in Kyoto, Mibu Roshigumi was appointed to guard the Ohanabatake-mon Gate.
長州藩を京都政局から排するために中川宮朝彦親王（尹宮）、会津藩、薩摩藩主導の八月十八日の政変が起こると、壬生浪士組は御花畑門の警護担当となった。