"The sun rises in the east and rains in the west, but there is a sunny day when there is no sunshine" is from Liu Yuxi's "Two Bamboo Words - One of Them".
Two Bamboo Words - Part I
The willow is green and the river is level, and I hear the sound of singing on the river.
The sun rises in the east and the rain falls in the west.
Translation:
The willows are wide and flat, and I hear the voice of my lover singing on the river. The sun rises in the east and rains in the west, but there is a clear sky.
The "Bamboo Branch Lyrics" is a kind of folk song from eastern Sichuan in ancient times, in which the people danced and sang, accompanied by drums and piccolos. The winner of the song competition is the one who sings the most Liu Yuxi, when he was the assassin of Kui Prefecture, was very fond of this kind of folk song.
Learning from the spirit of Qu Yuan's "Nine Songs," he adopted the scores of the local folk songs and made a new "Bamboo Branch Lyrics," which depicted the local landscape, customs, and love between men and women and was rich in the flavor of life. The genre is the same as that of the seven-word stanzas. However, in the writing, more white descriptive techniques are used, fewer allusions are used, and the language is fresh and lively, vivid and fluent, with a strong flavor of folk songs. Liu Yuxi composed several Bamboo Branch Lyrics, and this is one of them.
Expanded Information: 1. Background of the Composition Liu Yuxi wrote his works from the first month of the year 822 A.D. (the second year of Changqing of the Tang Emperor Mu Zong) to the summer of the year 824 A.D. (the fourth year of Changqing) at the Kui (kuí) Prefecture as an assassin, he composed eleven Bamboo Branch Lyrics. This is one of them. 2. Author's Biography Liu Yuxi (772-842), courtesy name Mengde, Han nationality, a native of Pengcheng (present-day Xuzhou) in the Tang Dynasty of China, with an ancestral home in Luoyang, was a literary scholar and philosopher of the Tang Dynasty, claiming to be a descendant of the King of Shanjing of Hanzhong, and a former supervisor and royal inspector of the Imperial Household, who was a member of the political reform group of Wang Shuwen. He was a famous poet in the middle and late Tang Dynasty, known as "Poetry Hero". His family was a scholarly family with generations of Confucianism. He was one of the central figures of Wang Shuwen's political reform activities. Later, he was relegated to the post of Secretary of Langzhou after the failure of Yongzhen's revolution. Baidu Encyclopedia - Two Songs on Bamboo Branches