@prometheanbound You're definitely right on the significant role of the Cold War. Another factor is that China (more accurately, the Chinese mainland) has become a new capitalist power that challenges the hegemony of the USA, which has controlled Japan since occupying it after World War II. Therefore Japan is used by America as the bridgehead against Chinese expansionist ambition. As a result, extrem nationalist sentiments have been agitated by the ruling class in both China and Japan against one another.