The Satsuma force led by Hisamitsu entered Edo accompanying an Imperial envoy. His aim was to reform the Tokugawa Shogunate. Meanwhile, Tenshō-in was anxious if Tatewaki also came to Edo accompanying Hisamitsu. Against Hisamitsu's wish, the negotiation between the envoy and Rōjū came to a dead end. Hisamitsu became extremely impatient and ordered Ōkubo to threaten the Rōjū side by force. While Tatewaki felt awkward toward such a forceful approach taken by his comrades, Satsuma succeeded in pressing on the reform plan.
