Their 1998 single "Winter Fall", became their first number-one single on the Oricon charts. They released the album Heart on February 25, 1998. Ark and Ray were released simultaneously on July 1, 1999, and became the first Japanese albums to be released simultaneously in many other Asian countries. Both topped the Oricon music charts, with Ark occupying number one and Ray at number two. The release of Ark and Ray marked the commercial high point of the band's career, with each selling over two million copies.
Their next album Real was released on August 30, 2000. However, it was their last studio album for some time. "Stay Away" from the album Real was featured in Drum Mania 4th Mix, making the song playable on the machine.
