"I always found it really strange," says Natalie Maya Willer, 30, a photographer based in London, "how I thought I could spot half-Japanese people in the street. . . . Then at the same time, with me not really looking Japanese, I also wondered if there really isn't a half-Japanese look after all!"

Willer, whose mother is Japanese and father is German, is explaining the genesis of "Hafu," an ongoing project about half-Japanese identity, created in collaboration with sociologist Marcia Yumi Lise, 27, who has a Japanese mother and American father.

Juxtaposing Willer's photography with Lise's social research, "Hafu" focuses on the physiological features of half-Japanese participants while also delving into their various backgrounds and perspectives. It began last October with an exhibition at the Bodhi Gallery in London, which was followed by seminars, workshops and forums that invited half-Japanese, Japanese and non-Japanese to share their experiences.