Face to face with the threat of an invasion by western powers in the 1850s, Japanese scholars and officials searched for a way out of the crisis. Sakuma Shōzan was among the first to stress and prove the viability of Neoconfucian learning by including selective aspects and achievements of western civilization such as military science. In doing so, he contributed much to the process of transition from valuing static ethic norms toward combinib these norms with realistic approaches and seeking practical knowledge as a new yardstick for decision-making.