The anti-Japanese demonstrations in China in April 2005 and the Japanese reactions have been characterized as a "clash of nationalisms.” This article examines in detail the nature of contemporary nationalism in both China and Japan, taking a number of current issues in the bilateral relationship as case studies. It differentiates between state and popular nationalism and between assertive and reactive nationalism. Focusing primarily on popular nationalism, the authors contend that in both China and Japan, contrary to perceptions within each country that the other country is practicing assertive nationalism, in fact reactive nationalism better encapsulates the type of nationalism that is occurring.