In the meantime, Shinsengumi (a group who guarded Kyoto during the end of Tokugawa Shogunate), under the control of the Aizu clan and in charge of protecting Kyoto at the time, killed several supporters of sonjo party, including members of the Choshu clan in the Ikedaya incident; this added fuel to the debate in Choshu domain and the Choshu troops finally moved to Kyoto.
折から京都治安維持に当たっていた会津藩預かりの新撰組が、池田屋事件で長州藩など尊攘派の志士数人を殺害したため、火に油を注ぐこととなり、ついに長州藩兵は上京。