In 581 AD, Emperor Wen of Sui, Yang Jian, seized power from the Northern Zhou dynasty and established the Sui dynasty. With vast territories and a united court working in harmony, the nation flourished, posing a serious threat to the weak Chen dynasty along the lower Yangtze River.
In 582 AD, Emperor Xuan of Chen died, and his son Shubao ascended the throne, known historically as Chen Houzhu. He was a reckless tyrant who ignored the nation's welfare, indulging only in pleasure. Besides his empress, he took ten beautiful consorts, including Zhang Lihua. In 584 AD, he launched a massive construction project, building three magnificent towers where he feasted and reveled day and night with Zhang Lihua and his other consorts, living a life of extravagant luxury.
To fund his lavish lifestyle, the last ruler appointed Shen Keqing, a ruthless imperial secretary, to oversee the treasury. Shen Keqing bled the people dry with merciless taxes, tearing families apart and leaving countless homes in ruin. The kingdom teetered on the brink of chaos, with resentment boiling over among the common folk.
At first, Emperor Wen of Sui had no intention of conquering the Chen kingdom, and the two states exchanged letters regularly. But then, Chen's ruler, the self-important Houzhu, overestimated his own strength and wrote an insulting letter. Emperor Wen was furious. His minister Yang Su and others repeatedly urged him to destroy Chen. The emperor outwardly showed no emotion, but inwardly he was already plotting.
A few days later, Emperor Wen said to his chief minister Gao Jiong, "The people south of the river have been tormented by Chen Shubao. How can we sit idly by and not rescue them? Go quickly and oversee the construction of ships to prepare for crossing the river."
Some advisors urged Emperor Wen of Sui to keep his shipbuilding plans secret, but the emperor replied, "What I do is in accordance with Heaven's will—there is no need for secrecy. I only hope the Chen ruler will awaken and repent."
In 587 AD, Xiao Yan and Xiao Huan, imperial relatives of the Later Liang who had previously submitted to the Sui Dynasty, suddenly fled to the Chen Dynasty. Chen's last ruler, Chen Houzhu, not only welcomed them but also appointed them to high positions. This was the final straw for Emperor Wen of Sui, who declared, "I can no longer tolerate this," and resolved to launch a military campaign to conquer Chen.
In the winter of 588 AD, Emperor Wen of Sui appointed his son, Prince Yang Guang of Jin, as supreme commander, leading a massive army of 500,000 troops divided into eight routes to launch a full-scale invasion of the Chen Dynasty.
When border guards spotted the Sui army's massive invasion, they immediately dispatched urgent messengers to the capital. But the ministers in charge of confidential affairs, Shi Wenqing and Shen Kegu, suppressed these reports, keeping Emperor Chen Houzhu in the dark. Yet news eventually leaked out. To everyone's astonishment, the emperor nonchalantly declared, "Jianye (the Chen capital, modern-day Nanjing) is blessed with imperial destiny. In the past, both the Qi and Zhou dynasties invaded multiple times and failed. Now the Sui army comes—they'll surely meet the same fate."
After saying this, he continued reciting poetry and making merry, showing no concern for the Sui army at all.
In the spring of 589 AD, with the help of Chen general Ren Zhong, the Sui army breached Jianye, capturing Emperor Chen Houzhu and his beloved consort Zhang Lihua. Thus fell the Chen dynasty, a neighbor to the Sui across a narrow stretch of water.
Later, people used the idiom "a narrow strip of water" to describe two regions separated by water but extremely close.
Source: *History of the Southern Dynasties*, "Biography of Chen Houzhu"
Meaning of the Idiom: Later, the Chinese idiom "一衣带水" came to describe how two regions separated by water but extremely close.