South Korean vocalist BoA is a rarity in that she is as big a star in Japan, Asia's largest music market, as she is in her homeland. Often recording multiple versions of her songs in Korean, Japanese, and English, BoA has also won fans in China, including Hong Kong and Taiwan, and Singapore. As a teen pop phenomenon who made her debut at age 14 in 1999, BoA has inevitably been compared to Britney Spears. But her easy-on-the-ears dance-pop and American-style R&B, including a regular offering of ballads, means she is more often compared to Japanese pop's biggest stars, Ayumi Ham...