The incident involved the Shinsengumi (a group who guarded Kyoto during the end of Tokugawa Shogunate), that maintained public order in Kyoto, attacking and capturing eight retainers of the Tosa clan who tried to pull out a noticeboard at Sanjo-ohashi Nishizume (the west foot of the Sanjo-ohashi bridge).
当時京都の治安維持を行っていた新選組が、三条大橋西詰の制札を引き抜こうとした土佐藩8名を襲撃、捕縛した事件。