Rythem was a Japanese pop duo consisting of two female members, Yui Niitsu (新津 由衣, born August 17, 1985) and Yukari Katou (加藤 有加利, born April 3, 1985) which disbanded in 2011.

They were signed to Sony Music Japan. In addition to their vocals, Yui played piano while Yuka played guitar.

Rythem was known for flowing, fluid harmonies and cheerful, upbeat melodies.

(Source: Wikipedia)