Definition: A narrow strip of water. Although there are rivers, lakes and seas separated, the distance is not far enough to be an obstacle to communication.

Allusion: During the Northern and Southern Dynasties, the Northern Zhou Dynasty in the north and the Chen Kingdom in the south were bounded by the Yangtze River.

Yang Jian, the prime minister of the Northern Zhou Dynasty, abolished Emperor Zhou Jing and becameeror himself, establishing the Sui Dynasty.

Determined to destroy the state of Chen, he once said: I am the parent of the people of the whole country. Can I watch the people of the South suffer and not save them just because there is a Yangtze River as narrow as a belt?

Later, people used a strip of water as a metaphor for two places that were only separated by a narrow strip of water and were very close together.