On April 14, 1867 (March 10 according to the old calendar), a plan by Kashitaro ITO (who broke away from the Shinsengumi and organized the Goryo-eji (guards of Imperial mausoleums, also known as Kodaiji-to) and led a movement to revere the emperor and overthrow the shogunate) to assassinate Isami KONDO (head of the Shinsengumi) together with Satsuma was outed by Hajime SAITO, a spy that was sent from the Shinsengumi.
慶応3年3月10日(旧暦)（1867年4月14日）、新選組を離脱し御陵衛士（高台寺党）を結成した伊東甲子太郎は勤王倒幕運動に勤しみ、薩摩と通謀して近藤勇を暗殺しようとたくらんでいる事が、新選組が間諜として潜り込ませていた斎藤一によって明らかとなった。