The Chang hen ge (长恨歌; lit. "The Song of Everlasting Regret/Sorrow") is a Tang dynasty poem by Bai Juyi (772-846) retelling the story of Yang Guifei (719-756), concubine of the Emperor Xuanzong of Tang. The poem is dated from 809.
A long list of literary, political, visual, musical and film works have been based on or referenced the Chang hen ge. Influence started almost immediately the poem had been written. Bai Juyi's friend Chen Hong (fl. 810s) created a dramatic version, Chang hen zhuan, which later inspired Rain on the Paulownia Tree (Wutong yu) by Bai Pu (1226-after 1306) and The Palace of Eternal Youth (Changsheng dian) by Hong Sheng (洪升, 1645-1704).
Painter Li Yishi (李毅士, 1886-1942) illustrated the poem with a series of thirty paintings. In classical music the poem has been set as a cantata by Huang Zi (1933) and as an orchestral song by Mo Fan (1991). The poem is referenced in the writings of Mao Zedong.
Author Madeleine Thien quotes from the poem in the closing pages of her award-winning 2016 novel, Do Not Say We Have Nothing.