Double is a Japanese R&B project that formed in 1997. It originally consisted of two sister-related singers, Takako and Sachiko,both of whom were
sisters. The duo was starting to become more noticed in the R&B world, until the sudden death of oldersister Sachiko in May of 1999. Takako,
however, decided to keep Double alive, and Double went on to become one of the mostsuccessful R&B names in the 2000's within Japan.