“There is still some racial thing going on,” claims a mild-mannered Crystal Kay. “Some people can’t accept there are a lot of foreigners out there, even in the industry.” The 23-year-old is the original pioneer for interracial artists in Japan, and with eight top-10 albums under her belt, she is currently celebrating 10 years in the business with her first ‘‘Best of’’ collection and a tour. Effortlessly glamorous in the office of her record company in Nogizaka in the Minato district of Tokyo, she is charming and modest about her impact on a J-pop scene that is increasingly discovering mixed-race acts.