The Choshu vanguard, who sought to directly appeal to the emperor and to remonstrate against the shogunate upon their death, rebelled against the Tokugawa government at the Hamaguri Gate after requesting a main army of 2,000 soldiers under the command of Prince Sadahiro of the Choshu clan to retreat from the Seto Inland Sea.
天皇直訴と集団諫死に賭けた長州先発隊は、まだ瀬戸内海上にいる世子定広率いる長州軍本隊二千名に引き上げを要請した上で、蛤御門の変（禁門の変）を敢行する。