Sonnō jōi
With increasing anti-Shogunal activities on part of Satsuma Domain to the south and Chōshū Domain to the east, and with neighboring Saga Domain showing signs of leaning towards the anti-Tokugawa Alliance, the situation in Shimabara domain was increasingly uncertain. To compound the situation, Tadakazu was ordered by Edo to lead his forces against Chōshū in both the First Chōshū Punitive Expedition of 1864, and Second Chōshū Punitive Expedition in 1866. Both expeditions were extremely unpopular among his "samurai", many of whom had fallen under the influence of the Sonnō jōi movement.