Abstract: Japans security think tank, though limited in its role in policy formulation, still has considerable influence. The think tanks with certain influence in the field of Japanese security and defense can be divided into four categories: official research institutions, quasiofficial professional think tanks, research institutions affiliated with economic units, various ad hoc advisory committees or groups. These think tanks influence Japans security decisionmaking mainly in three ways: bottomup, topdown, and plane convection. Generally speaking, the fourth of the four categories of think tanks, different from those in other countries, plays an important role in the formation of important security decisions and documents in Japan, which can be called the “alternative Japanese type” security think tank. In the current era, the research contents and political positions of the Japanese security think tanks, including other types of think tanks, have obvious values and policy tendencies, which pose realistic challenges to the improvement of SinoJapan relations and Chinas public diplomacy towards Japan.

Key words: Japan, think tank, alternative type, security policymaking, influence