At this moment, Li Shimin could not help but sigh inwardly once more.
War really was simpler.
Seeing Rome divide itself into East and West and establish four emperors, Li Shimin had been briefly startled, but after thinking it through, it was not something he could not understand.
After all, from ancient times to the present, there had been very few realms whose territory could reach such vastness. On this point, he understood all too well.
The most direct problem brought about by an enormous domain was difficulty in governance. And the problems contained within that difficulty, if explained using the terminology of later generations, came down to the misalignment of multiple centers, which inevitably gave rise to instability.
How was the central authority to regulate matters properly, so that the people of the southeast, who paid taxes, would willingly support soldiers stationed in the Western Regions?
This was an extremely difficult problem.
Handle it poorly, and frontier troops would go hungry, taxpaying civilians would be oppressed, resentment would boil over, and chaos would arise of its own accord.
However, judging from the histories of the Han and Tang so far, a dual-capital system might be workable.
From Rome's experience, on the other hand, a system with multiple emperors carried dangers that were simply too great.
Still, these questions were ultimately distant ones. Li Shimin would need to think through them himself first, grasp at least a thread of understanding, before it would be appropriate to raise them with capable ministers for discussion. Thus, in the end, he shifted his gaze back to the light screen.
When he saw the two characters Guangshen appear again, he could only laugh bitterly, followed by a sigh.
"To recklessly spend millions of lives to build such a grand undertaking. Truly… extravagant."
It was because of this Guangshen that the chaos at the end of Sui had erupted, countless people had died, and even now the vitality of the realm had not recovered.
Li Shimin did not even dare imagine that if the people of Great Tang at present numbered fifty million, as they had during the Daye era, would he really need to be so cautious when advancing into the Western Regions?
But it was only idle speculation. Shaking his head, he turned his attention to the few short lines concerning Pan Jixun.
"This method of controlling the Yellow River…"
Before he could finish speaking, Li Shimin felt someone tug sharply at his sleeve.
"Your Majesty, this method requires only three days for me to verify its effectiveness. If it can prevent Yellow River floods, I beg to take on this task."
The words came out fast and urgent. It was only then that Li Shimin clearly saw that the one pulling at his sleeve was none other than Yan Lide.
In such a situation, there was little choice but to grant his request.
Having received permission, Yan Lide retreated happily, already feeling that his record in the history books would likely gain a few more lines.
If one spoke of the simplest way to leave one's name in history and earn shrines from the people, governing the Yellow River surely counted as one.
Of course, this simplicity was only in comparison to feats like Champion Marquis Huo Qubing charging deep into the northern deserts. If flood control were truly easy, why would the Yellow River's great calamities and minor disasters never cease?
Yan Lide was skilled in architecture, and thus also had considerable knowledge of waterworks. He knew well that the Yellow River's greatest problem lay in its complex channels, which made it extremely difficult to clear sediment blockages in dangerous sections.
Now that the light screen had practically thrown the core method right into his face, Yan Lide felt that failing to seize this opportunity would be unforgivable.
Yan Lide was content. Li Shimin was pleased. Ruler and minister exchanged smiles, and the atmosphere was exceptionally harmonious.
As for the so-called livelihoods of a million canal workers, Li Shimin did not comment on it.
From the looks of things, there were likely other underlying problems that had led the Ming dynasty to make what seemed like such a shortsighted decision.
As for the precise reasons, they would probably only become clear in the future.
[Lightscreen]
[First, one must understand a basic concept. From as early as the Western Zhou, China's urban planning systems were already highly mature.
As a counterexample, Rome fits perfectly. Ancient Rome was a naturally accreted city, lacking systematic planning.
Its innate environment could not meet later demands. When population exploded, Roman craftsmen discovered that the terrain was mountainous and the geology largely rocky. With the technology of the time, it was impossible to excavate large-scale underground channels, so building elevated aqueducts became a forced choice.
Meanwhile, during the Qin and Han periods, our ancestors were already dissatisfied with planning a single city and began experimenting with regional urban cluster systems.
Taking Han Chang'an as an example, after peace was restored, the rapidly growing population overwhelmed the city. Under official planning, certain functions that could be centralized were quickly relocated to surrounding satellite towns.
At its peak, Chang'an's metropolitan area contained as many as fifty seven smaller cities. Each performed its own role, supporting the entire Chang'an urban cluster in orderly fashion.
For example, cities like Zheng County and Xiayang were specifically assigned iron offices, concentrating iron smelting and forming the prototype of modern industrial zones.
Cities such as Liyang and Huixian were built along rivers and managed canal transport, housing massive granaries that redistributed supplies to Chang'an and its satellite cities.
Lianshao County established a salt office to supply salt to the Guanzhong capital region. The Ship Office was the imperial shipbuilding authority, which directly built a new city from scratch, hence its name, and was also a purely functional satellite city.
Such advanced and comprehensive planning naturally included water supply systems. Famous examples include the Lingqu Canal and the Zhengguo Canal. These projects primarily served to bring water for daily urban use, while irrigation of farmland, which many people associate them with today, was actually a secondary function.
The most typical case was the Longshou Canal, which stretched seventy kilometers and lay thirty meters underground.
This canal was built during the reign of Emperor Wu of Han. It took nearly ten years and tens of thousands of workers, ultimately diverting the Luo River into Chang'an, becoming the first underground water diversion canal in Chinese history.
If one compares the Longshou Canal with ancient Rome's elevated aqueducts, which was more difficult is immediately obvious.
Most Roman aqueducts were only a little over ten kilometers long. Even including tunnels, a complete aqueduct rarely exceeded one hundred kilometers.
The Longshou Canal, by contrast, ran seventy kilometers entirely underground. As everyone knows, underground canal construction involves determining elevation gradients, planning routes, selecting water sources, surveying geological conditions, and calculating water flow distribution. The technical foundations required by the two systems were simply not on the same level.
This construction method of the Longshou Canal is now referred to as the well canal system. After the Han conquered the Western Regions, this technology rapidly spread into Central Asia, received widespread praise, and continues to be used to this day. Among the people it became known as the karez, a topic also covered in history textbooks.
Furthermore, after the Han dynasty, civilian water usage technologies continued to develop. Modern film and television often depict ancient water drawing with bucket-and-windlass systems regardless of dynasty, which is somewhat stereotypical.
For instance, many believe that hand-operated water pumps were a twentieth-century invention, but in reality, many wealthy households during the Song dynasty were already using them.
Some scholars even argue that such devices originated in the Han dynasty, though currently there is no definitive archaeological evidence to support this, and we can only await future discoveries.
Waterworks have always run through the entirety of Chinese civilization. Even the Great Wall, familiar to many, was not purely a military structure. Rammed-earth walls are highly vulnerable to water damage, and ancient builders devoted significant thought to this problem. Watchtowers and walls varied in height, drainage ditches were cut beside horse traps, connected to culverts that directed water down slopes, and both culverts and drains featured self-clearing designs to prevent silt buildup.
This is one reason why the Great Wall still stands today. Structures hundreds or even thousands of years old, long after losing their military function, still retain fully operational drainage systems, which alone demonstrates their technical sophistication.
The technical merit of Roman elevated aqueducts was actually inferior to that of the primitive concrete used to build them. That was the true black technology behind Roman architecture.
The Apennine Peninsula's vast volcanic systems provided ample volcanic ash. The Romans discovered that mixing it with slaked lime and clay produced a material of astonishing hardness once set, allowing them to build many magnificent structures.
This was something ancient China truly could not replicate. The nearest source of volcanic ash lay on Hainan Island, and the human labor costs would have been astronomical.
Although there existed a downgraded substitute using iron slag instead of volcanic ash, its effectiveness was greatly reduced and far inferior to true volcanic ash.]
As images rotated across the light screen, Liu Bei also saw those towering Roman aqueducts. His first reaction was disbelief. How could something so grand lack technical sophistication?
But as the explanation unfolded and twisted, Liu Bei's emotions rose and fell.
Just from the sheer magnificence of Roman buildings, it was obvious how useful that concrete must have been, and it made Liu Bei's heart itch.
He even began considering whether he should write to Shi Xie and trade ironware for some of it.
But when he heard the formula at the end, he was instantly overjoyed.
Iron slag?
We have that. And we have plenty of it.