Heartsdales was a Japanese-American hip pop duo composed of sisters Yumi Sugiyama (杉山ユミ, Sugiyama Yumi?) and Emi Sugiyama (杉山エミ, Sugiyama Emi?), known by their stage names Rum and Jewels, respectively.

Yumi was born on December 17, 1981 and Emi on December 4, 1976 in Tokyo, Japan. Their family moved to the Yonkers area of New York right after Yumi was born, due to their father's job as an interior designer. In 1995, the family moved back to Japan, and Yumi attended Tama Art University and Emi attended Keio University.

In summer 2001, Yumi and Emi appeared on the TV audition program Asayan after sending in a demo. They won the competition, and landed a contract with Avex Entertainment. They adopted the name "Heartsdales" as a reference to the hamlet of Hartsdale, New York.

They released their first album, Radioactive, in 2002 under Avex Record's sublabel Cutting Edge. Their first single, "So Tell Me," was ranked 6th on the Oricon music rankings. Since then, they released 6 albums and 14 singles. Artimage is Heartsdales' management office, who also manages other Japanese hip-hop artists such as M-Flo and Double.

On June 22, 2006, Heartsdales announced on their official website that they were going to split up to pursue new endeavors. Yumi now lives in New York City and has started a design studio, "Studio Yumi," and attends the Parsons The New School for Design. Emi lives in Tokyo.

Yumi announced on her blog that she gave birth to her son weighing 7.7 pounds (3.5 kg) on June 25, 2010.