徳川家重
The assassination of Ii Naosuke in the Sakuradamon Incident changed the Shogunate's policy, allowing Matsudaira Shungaku to return to politics in April 1862. he strongly supported the "kōbu gattai" movement to strength the relations between the shogunate and the Imperial court. He was appointed to the newly-created post of "Seiji sōsaishoku", a high-ranking government oversight position and worked with Matsudaira Katamori ( "daimyō" of Aizu Domain), who was appointed Military Commissioner of Kyoto, who was in charge of security for the Emperor. In 1862, Shungaku formed the Rōshigumi, a group of "rōnin" organised as a paramilitary militia to help guard Shogun Tokugawa Iemochi on his 1863 trip to Kyoto. He also invited Yokoi Shōnan from Kumamoto Domain as a political consultant, and planned at Shogun Tokugawa Ieshige relocate to Kyoto. These actions were known as the Bunkyū Renovation after the Japanese era name. In 1863, the Rōshigumi were transformed into the Shinsengumi. Matsudaira Shungaku moved to Kyoto the same year, but the increasing strength of the "Sonnō jōi" movement led by the Chōshū Domain forced him into increasingly unfavourable compromises, and he was forced to resign as "Seiji sōsaishoku" in disappointment.