However, the Satsuma clan, which was ordered to attack Choshu from the Hagi-kuchi route, had formed a secret alliance with Choshu (Saccho meiyaku [pact between Satsuma and Choshu]) through the mediation of Ryoma SAKAMOTO of Tosa Domain and refused to dispatch the troops.
しかし萩口を命じられた薩摩藩は、土佐藩の坂本龍馬を仲介とした薩長盟約で密かに長州と結びついており出兵を拒否する。