A body of water as thin as a belt or a sash
Indicates that places or people are separated only by water; indicates that the interactions between people and goods are frequent and unaffected by small distance between them
Neutral
我们常说中日两国一衣带水 | Wǒmen cháng shuō zhōngrì liǎng guó yīyīdàishuǐ
We often say that Japan and China are neighbors separated only by a thin body of water
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地处长江三角洲，与国际大都市上海一衣带水，隔江相望 | Dìchǔ chángjiāng sānjiǎozhōu, yǔ guójì dà dūshì shànghǎi yīyīdàishuǐ, gé jiāngxiāngwàng
Located in the Yangtze River Delta, it is directly across the water from the international metropolis of Shanghai
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《南史》(Nán Shǐ), a work by 李大师 (Lǐ Dà Shī) and his son 李延寿 (Lǐ Yán Shòu). The work covers the history of the four Southern Dynasties (宋, 齐, 梁, and 陈) and is generally known in English as "History of the Southern Dynasties."
During the Northern and Southern Dynasties (南北朝 | Nán Běi Cháo | 420 - 589), China was split in two. The land to the north of the Yangtze River (长江 | cháng jiāng) was controlled by the Northern Bei Dynasty (北周, Běi Zhōu), while 陈国 (Chén Guó) controlled the land to the south.
In 581, the prime minister of 北周, 杨坚 (Yáng Jiān), deposed the 8-year-old emperor and founded the Suí Dynasty (随, 581 - 617) with himself at its head. He quickly implemented a series of policies that led to a substantial increase in the country's might, and he began to consider how to capture 陈国.
On the other side of the river, the cruel ruler of 陈国 noted the changes, but didn't think his territory could actually be attacked. After all, nobody could wage a battle across the 长江. He continued with his usual policies, which greatly abused the common people.
Some years later, the emperor of 隋 was ready for his assault. Before his troops set out, he commented to one of his officials, "I'm the parent of all commoners. How can I let such a thin strip of river stop me from saving the commoners on its other side?"
In the end, the 随 emperor's assault was successful, and he defeated 陈国.