Japan is often perceived as an ethnically and culturally homogeneous whole. However, recent debates about Japanese identity igniting social media in the archipelago do not fail to question this assertion. Indeed, the emergence of a large number of multiethnic TV personalities, called hafu in Japanese, questions the foundations of japanity: what does this term mean and where does its problematic “only-half-of” connotation come from, which can be inclusive or exclusive of Japanese identity according to circumstances? This term highlights the many issues that have been linked to racial purity and state racism that are supposed to guarantee the foundations of a healthy nation in both Japan and the United States, in a strong historical context of imperialist rivalry.