Architect Yoshimasa Yano is unable to recall the moment he first became aware that his perception of color differed from that of his family or friends.

In the fourth grade of elementary school, however, Yano failed a color vision test. His parents weren't surprised by the result.

"My parents took a variety of measures to ensure I didn't embarrass myself in public," says Yano, who insisted on using a pseudonym when speaking about his condition.