On July 23, 1864, the order of the Imperial Court (First conquest of Choshu) to attack Choshu was issued, and on 24th, Yoshinobu TOKUNAGA commanded twenty-one domains of Saikoku to send troops, and Satsuma planned to respond to this order and extend its power.
元治元年7月23日に長州藩追討の朝命（第一次長州征伐）が出、24日に徳川慶喜が西国21藩に出兵を命じると、この機に乗じて薩摩藩勢力の伸張をはかるべく、それに応じた。