But as Duncan Ryuken Williams, a professor of religion and East Asian languages and cultures at the University of Southern California, who organized the festival, explained, it’s more complicated than that, a subject worthy of deep — and optimistic — exploration. The festival coincided with a conference at the University of Southern California on critical mixed-race studies, and the publication of “Hapa Japan,” a two-part volume of essays that Professor Williams edited.

The scholars, artists and musicians I met over four days embodied that complexity. They all shared some version of the same story: of boundary crossing, first by their parents, then by themselves, in lives that unavoidably tested rigid racial assumptions and expectations. For all that, they seemed comfortable in their skins, and strikingly creative: A singer-songwriter, Kat McDowell, of New Zealand and Japan, trying to make it in Los Angeles. A pop and hip-hop trio, the Yano Brothers, who were born in Ghana, grew up in Japan, and rapped smoothly in Japanese. Tetsuro Miyazaki, a Belgian-Japanese photographer. Jeff Chiba Stearns, a Japanese-Canadian filmmaker whose documentaries include “One Big Hapa Family.”

If you gaze at the many portraits of half-Japanese, half-Dutch subjects photographed by Mr. Miyazaki, you can see the searching in their faces, the puzzling out of what hapa means. But you can also gain the sense that there are deep currents, forces old and powerful, in opposition to wall-building and racial hunkering.

Mixing is happening all around, and the results can be surprising, wondrous, and unstoppable: Who knew that there were so many hapas in Holland? Yet in the hapa world, anxiety about breeding and bloodlines is never far from the surface. An essay in “Hapa Japan” recounts the paroxysms felt by some Japanese-Americans in California in the late 1970s, when an article in a newspaper of the Japanese American Citizens League warned that interracial marriage was a threat “worse than a hundred million Manzanars, Tule Lakes, or Pearl Harbors.”

Young couples, thankfully, did not heed that panicky call to preserve issei purity. As Professor Williams told me, Japanese-Americans “marry out” far more than other Asian-Americans. In the 2010 census, more than 460,000 of 1.3 million Japanese-Americans identified themselves as multiracial. The trend puts Japanese-Americans on the brink of becoming the first Asian-American group that is mostly racially mixed.