Tao Yuanming, a famous writer of the Eastern Jin Dynasty , wrote the well-known essay Peach-Blossom Spring. In it he tells a story which goes like this: A fisherman happened to come upon a place called Peach-Blossom Spring. Squeezing through a cave, he found a village, the residents of which were descendants of refugees from the Qin Dynasty. It was a paradise isolated² from the outside world, without exploitation or oppression, and everybody living and working in peace and contentment(满足) . The fisherman left the villagers and went home. But he could never find the peace again.

This idiom is derived³ from the above story, and it is used to mean an isolate¹, ideal world.