日米和親条約
While a "rōnin", Ryōma decided to assassinate Katsu Kaishū, a high-ranking official in the Tokugawa shogunate and a supporter of both modernization and westernization. However, Katsu Kaishū persuaded Ryōma of the necessity of a long-term plan to increase Japan's military strength in the face of Western influence that led to the Convention of Kanagawa. Instead of killing Katsu Kaishū, Ryōma started working as his assistant and protégé.