Chapter Thirty: Water Binding the Sand

When it came to Li Shangyin’s talent for poetic lines, Pei Min felt quite reassured. With the foundation of “The Brocade Zither,” the most crucial project in this field, he knew earning top marks would be no problem. He, at least, had no worries about this. He was far more confident than He Zhizhang and Zhang Xu, who were more anxious about today’s examination. Having spent many days together, they had never seen Pei Min compose poetry or write prose, and as soon as he returned home, they asked him anxiously how things had gone.

Pei Min’s self-assured expression put their minds at ease. Little did they know, poetry and prose were not Pei Min’s forte, yet if it came down to examinations, no one alive could surpass him in this subject—not even Li Bai or Du Fu. This was the greatest advantage he possessed as a traveler from another time.

Even if Li Bai had “Song of the General Advancing” and “Hard Roads in Shu,” and Du Fu had “Spring View” and “Ascending the Heights,” what of it?

He had at his disposal the “Ballad of the Pipa” and “The Charcoal Seller” by Bai Juyi, the Poet Demon; “Inscription of the Humble Room” and “Black-Clad Lane” by Liu Yuxi, the Poet Hero; “Moon Over the Passes” by Lu You, the God of Poetry; and memorable lines from Meng Jiao, the Prisoner of Poetry; Luo Ye, the Tiger of Poetry; Li He, the Ghost of Poetry; as well as Su Dongpo and Xin Qiji. All these masterpieces were available to him in his memory.

Pei Min’s supposed weakness was, in fact, his greatest strength, and even he was unsure whether to laugh or cry at the irony.

The third round was the policy essay. Though this era valued poetry and prose above all, Pei Min felt that the policy essay was the true essence of the imperial examination. Practical affairs, after all, were the foundation of officialdom; no matter how lofty one’s poetic achievements, they were confined to the realm of art. To compose poetry was no guarantee of being a good official. The policy essay was different—it tested one’s ability to govern and enact policies, though there was always the risk of empty talk. Still, he believed that being able to talk on paper was better than not knowing anything at all.

Pei Min always thought that if Zhao Kuo hadn’t encountered the unrivaled Bai Qi, and if the King of Zhao hadn’t overestimated him and placed him at the head of the armies from the start, but instead allowed Zhao Kuo to gain experience step by step, his achievements might not have matched his father Zhao She, but he would not have earned eternal infamy. Had Zhao Kuo combined knowledge with practice, perhaps he might have become a famed general.

Thus, Pei Min placed far greater importance on the policy essay than on the classics or poetry.

Looking at the examination questions in his hand, Pei Min rested his chin and pondered deeply. This round's examiners had provided two topics, covering both military and civil affairs: the first was on water management—how to control the flooding of the Yellow River; the second concerned border security—how to effectively prevent incursions.

Water management was, in ancient times, the foremost virtue of governance. The effectiveness of water control could benefit vast tracts of land, tens or hundreds of thousands of people, and their descendants for generations. The most renowned ministers in this field included Sun Shuao, Ximen Bao, Li Bing, Wang Jing, and Fan Zhongyan. Sun Shuao oversaw the construction of the earliest large-scale irrigation project, Shaopi, which irrigated thousands of acres and continued to serve its purpose for over two thousand years—even in the twenty-first century, it still provided irrigation benefits. Ximen Bao directed the building of the Twelve Canals on the Zhang River, diverting water to the fields, reducing floods while enriching the soil, benefiting the land for a millennium. Li Bing’s Dujiangyan, Wang Jing’s governance of the Yellow River and Bian River, Fan Zhongyan’s sea embankment—all were monumental feats of water management that benefited people for thousands of years.

However, Pei Min knew he must not be too ambitious. All these figures were prominent in their time, and their massive projects relied on great manpower and resources. Especially Wang Jing, who, to tame the Yellow River, employed more than half a million workers and spent vast sums, keeping the unruly river in check for eight hundred years. Overreaching was not the answer.

Biting his pen, he recalled one water management story after another, only to reject each in turn. Different eras, technologies, facilities, and rivers demanded different solutions; blindly copying would only create glaring flaws.

Suddenly, Pei Min thought of someone—Pan Jixun.

He slapped the desk and exclaimed, “I’ve got it!”

Noticing the proctor staring at him fiercely, Pei Min hurriedly made an apologetic gesture. Seeing that the proctor did not hold it against him, he excitedly prepared his ink and began to write:

“The highest strategy for water management is prevention. To manage water with people is inferior to managing water with water itself. The Yellow River is most turbid; by measure, sand makes up six parts, and by late summer, water only two. To carry eight bushels of sand with two pints of water—unless the flow is swift, stagnation is inevitable. When the water is divided, its force slows; with less force, sand settles; when sand settles, the river fills; every inch of water bears a surface of sand, raising its height. When water converges, its force increases; with greater force, sand is swept away; when sand is swept, the river deepens; fathoms of water reveal the riverbed, lowering its depth. Building embankments to constrict the flow and using water to scour the sand—so long as water does not overflow, it must scour the riverbed. This principle is certain, this outcome inevitable; thus, convergence is superior to division.”

He was writing about the ingenious method of “constricted flow and sand scouring,” devised by Pan Jixun, the Ming dynasty’s world-renowned hydraulic expert.

The difficulty of taming the Yellow River lay not in the water, but in the silt. According to twenty-first-century research, the Yellow River produces nearly 1.6 billion tons of silt each year. Most is carried to the sea, some accumulates in the lower reaches forming alluvial plains, and some settles on the riverbed, causing water levels to rise and threatening the banks. Thus, every so often, massive dredging operations are required, consuming enormous resources. In ancient times, without advanced technology, dredging the Yellow River was even more formidable.

Pan Jixun managed the Yellow River and Grand Canal four times, over twenty-seven years. Through his long experience, he absorbed the achievements of predecessors and comprehensively summarized China’s water management history, inventing the “constricted flow and sand scouring” method.

This method involved narrowing the river channel and using the increased water force to scour the riverbed, thus achieving dredging and flood prevention.

Three hundred years after Pan Jixun’s work, Western hydraulic experts with scientific knowledge enthusiastically proposed to the Qing government a system of double embankments along the Yellow River to slow the water, raise the embankments with silt, and prevent flooding. Their papers drew international attention, but they soon realized, to their embarrassment, that China had adopted this advanced method three centuries earlier in the Ming dynasty, and had done so with even greater expertise.

Pei Min, recalling this knowledge, wrote with divine inspiration, filling over a thousand words with a detailed explanation of the constricted flow and sand scouring method.

“Marvelous!” Pei Min suddenly noticed someone standing beside him—he looked up to see the proctor from earlier.

The proctor, seeing Pei Min had no intention of causing a disturbance, was curious to see what he had come up with.

His first impression was that Pei Min’s small script was exquisite, bearing the refined touch of Wang Xizhi, the Sage of Calligraphy. Reading closely, the method of constricted flow and sand scouring was laid out brilliantly, word by word, and he could not help but voice his admiration.