This term originates from Li Gongzuo’s 李公佐 (ca. 770-850) short story “Nanke taishou zhuan” 南柯太守傳 [The Biography of the Government of Nanke].
The story is about the knight-errant Chunyu Fen 淳于棼, a previously successful and rich officer in the Huainan army who has offended his general and been dismissed. He drinks himself to sleep under a huge pagoda tree and dreams of entering the kingdom of Huai’an 槐安 [pagoda tree in peace]. In it, he happily marries the daughter of the king, enjoys all the fortunes and glory, and becomes a great governor for the Nanke 南柯 [south branch] county. Later his wife dies and he returns home.
It is only then that he realizes that he has been in a dream for a few hours, and the kingdom he has been to is just a nest of ants at the root of the pagoda tree. Later, the term Nanke 南柯 or Nanke yi meng 南柯一夢 [a dream of Nanke] is used to describe an illusory dream or fantasy of grandeur that is doomed to vanish.
