우물 안 개구리.

The Korean idiom '우물 안 개구리' (umul an gaeguri) literally translates to 'a frog in a well.' Its origins can be traced back to an ancient Chinese fable, specifically from the collection of stories known as Zhuangzi (莊子), attributed to the philosopher Zhuang Zhou (c. 4th century BCE). The particular story tells of a frog living contentedly in a shallow well. It believes its well is the entirety of the world and boasts about its comfortable life to a sea turtle. The sea turtle, having seen the vastness of the ocean, attempts to describe the immense and boundless sea to the frog. However, the frog, limited by its own experience and environment, cannot comprehend the concept of something so much larger than its well and dismisses the sea turtle's description. This fable was introduced to Korea centuries ago and became deeply ingrained in its culture and language, evolving into the common idiom used today. The phrase effectively captures the essence of someone whose understanding or perspective is severely restricted due to a lack of broader experiences, education, or exposure to the outside world, much like the frog whose entire world is confined to its small well. It serves as a cautionary tale against narrow-mindedness and encourages individuals to seek wider knowledge and experiences to gain a more complete understanding of the world.