Chou wrote his second string quartet, "Streams" (2003) in response to Bach's Art of Fugue, which was commissioned by the Brentano String Quartet. In 2007, the gayageum master, Yi Ji-young, commissioned him to write a work for gayageum and an ensemble of traditional Korean instruments. Her group, Contemporary Music Ensemble of Korea (CMEK) premiered "Eternal Pine" in 2008. Chou wrote a version for western instruments, "Ode to Eternal Pine" (2009), for the New York New Music Ensemble (NYNME) and a version for traditional Chinese instruments, "Sizhu Eternal Pine" (2012; his first and only work for a full ensemble of Chinese instruments), for the Taipei Chinese Orchestra.