Heartsdales were a self-producing j-urban group, composed of two sisters Yumi Sugiyama (杉山ユミ) and Emi Sugiyama (杉山エミ), known by their stage names Rum and Jewels, respectively. The name Heartsdales comes from the area of Hartsdale, New York, where the sisters lived and grew up in. They are fluent in English, as well as Japanese. The group debuted in 2001, with the single So Tell Me (which remained their biggest hit throughout their career). They had a clear 80's and 90's American hip-hop influence in their music, and often included a full English version of their single as a B-side.