Flow's energetic, straight-ahead pop-rock comes from an unexpected combination of influences. The Japanese group's core duo, brothers Kohshi and Take, started out doing covers of their speed metal heroes, X JAPAN. But after X JAPAN's breakup in 1997, they began to pursue a new musical direction, adding looser, more easygoing rhythms inspired by hip-hop. The result is a sound that's optimistic, a little funky and guided by the two vocalists' effortless exchange of melodies.