The Boshin War broke out in 1868, and when the Bakufu army was defeated in the Battle of Toba-Fushimi, a large force of combined Satsuma and Choshu Domains advanced on Edo, putting the metropolis under the threat of warfare.
1868年に戊辰戦争が起こり、鳥羽・伏見の戦いで幕府軍が敗れると、薩摩藩長州藩軍の大軍が江戸に迫り、江戸は戦火に晒される危険に陥った。