Following the lifting of WWII-era restrictions imposed on exchanges and trade between Korea and Japan in the late 1990s, the first-generation girl group S.E.S became the first Korean artists to debut in Japan in late 1998 and their first album Reach Out in 1999. Young K-pop star BoA had Japanese language training before her Korean debut and when she debuted in Japan in 2002, her Korean identity was inessential. Her music style and fluent Japanese led her to be considered a part of J-pop. BoA's debut Japanese album released in 2002, entitled "Listen to My Heart", was the first album by a Korean singer to debut at the top of the Japanese Oricon Charts and become an RIAJ-certified "million-seller" in Japan. Since her Japanese debut, BoA has released several albums and all of them have topped the Oricon Charts.