Tao Yuanming, a famous writer of the Eastern Jin Dynasty (317-420), wrote the well-known essay Peach-Blossom Spring. In it he tells a story which goes like this: A fisherman happened to come upon（偶然见到） a place called Peach-Blossom Spring. Squeezing（压榨，推挤） through a cave, he found a village, the residents of which were descendants（后代，晚辈） of refugees from the Qin Dynasty. It was a paradise isolated¹（鼓励，绝缘） from the outside world, without exploitation or oppression, and everybody living and working in peace and contentment（满足，满意） . The fisherman left the villagers and went home. But he could never find the place again.

This idiom is derived² from the above story, and is used to mean an isolated, ideal world.