Ever since Liu Bei had established himself in Jingzhou, or more precisely, ever since they had officially opened the Department of Works here in Gong'an County, their iron smelting industry had been improving at an impressive rate.
The blacksmiths were producing more and more iron with each passing week, and the furnaces rarely seemed to stop working. Naturally, however, greater iron production also meant greater quantities of slag. Mountains of the stuff had begun piling up around the foundries.
The military planners had already come up with three straightforward ways to deal with this industrial byproduct, all of them perfectly practical and entirely lacking in anything resembling elegance.
The first was to return the slag to the blast furnaces and extract whatever usable iron remained. The second was to mix it into rammed earth when constructing fortifications. The third was to crush it into gravel and use it to pave supply roads.
All three methods followed the same principle. Waste nothing.
Unfortunately, circumstances had changed.
The fortifications around Jiangling City had already been completed, leaving the military engineers with little immediate need for more construction materials. Meanwhile, the foundries in Gong'an had recently undergone a major upgrade. They had switched to coal and installed heavily modified, water powered bellows capable of forcing superheated air into the furnaces.
The resulting increase in temperature was so great that the slag emerging from the furnaces contained almost no usable iron.
Re-smelting it would be a waste of fuel and labor.
As for using it to pave roads, that idea was beginning to lose its appeal as well. Slag was cheap, certainly, but the jagged black fragments scattered across the roads were hardly pleasing to the eye. Smooth river pebbles or neatly cut stone blocks were considerably more attractive.
Zhuge Liang remembered a passing remark in a letter his wife had sent him late the previous year. She had mentioned that the magistrates in Gong'an had been forced to set aside a large empty plot of land simply to store the growing mountains of iron slag.
When he had first read that letter, Zhuge Liang had merely smiled. To him, the expanding slag heap was a beautiful sign of their flourishing industry. Every pile of waste represented another batch of iron, another improvement to the foundries, and another step toward strengthening Shu Han's military capabilities.
But now, as he stared at the Light Screen and listened to the heavenly voice casually explain the miraculous potential of this architectural material, Zhuge Liang suddenly felt a strange sense of unease.
The slag was no longer garbage.
It was a resource.
And they had been throwing it away.
He began mentally calculating the amount of slag currently sitting in the Gong'an dump, along with the cost of transporting it and the number of workers who would be needed to process it. Before long, he was already considering whether they should build a secondary wall around the waste heap to prevent anyone from stealing it.
The thought of spies from Jiangdong sneaking into Gong'an and carrying away their precious slag was absurd, but Zhuge Liang found himself taking it seriously anyway.
What if the Romans really did use this stuff to build their cities?
What if they had some other use for it that we had not even considered?
The more he thought about it, the more he felt that they had been treating a treasure like a pile of rubbish.
As for the other two ingredients mentioned in the heavenly voice's explanation, neither was particularly unfamiliar to the people of the Han dynasty.
Slaked lime had been used as a binding material for walls since ancient times, while clay had been used to make pottery for thousands of years. Neither ingredient presented any real difficulty.
The real revelation was that these ordinary materials could be combined with iron slag to create a substance strong enough to construct buildings and roads.
While Liu Bei and Zhuge Liang were busy appreciating the strategic importance of industrial waste, Ma Chao was having an entirely different reaction.
The whole concept of technological innovation was still rather foreign to the fierce cavalry commander. Having grown up in the harsh northwest, Ma Chao was far more interested in the urban planning described by the heavenly voice than in the finer details of concrete production.
The idea of establishing separate cities for different industries was particularly appealing to him.
He imagined the capital region, with its orderly roads, specialized workshops, and carefully planned districts. It was a level of organization that would have been difficult to achieve in the rugged plains of Liangzhou, where even finding enough suitable land for a proper settlement could be a challenge.
Ma Chao thought of the magnificent city of Chang'an, whose grandeur had been praised for generations.
Then he remembered something else the heavenly voice had mentioned.
The original Han dynasty Chang'an had eventually been abandoned because its population had grown so large that the city's waste management system could no longer cope.
Ma Chao's romantic image of the imperial capital shattered instantly.
He turned toward the Light Screen with a deeply troubled expression.
"What's the point of having perfect urban planning if the entire city ends up drowning in human excrement?"
His voice was loud enough for everyone nearby to hear.
Before he could continue, Zhang Fei's hand shot out and clamped firmly beneath his chin, snapping his jaw shut.
The Third General had been listening to Liu Bei and Zhuge Liang discuss the miraculous building material with growing interest. He was not about to let some uncultured desert brat ruin the mood by bringing up something so disgusting.
Ma Chao glared at him furiously.
Zhang Fei ignored the murderous look and leaned closer to whisper, "Use your brain. According to our future descendant, those Romans went to extraordinary lengths to bring drinking water into their cities. I guarantee you they had absolutely no proper plan for getting rid of the dirty stuff."
Ma Chao's eyes widened slightly.
Zhang Fei continued, his voice full of confidence. "People across the ocean may look different from us, but they still eat, drink, and answer nature's call. The same problem that overwhelmed Chang'an must have existed in Rome as well."
---
Inside the Ganlu Pavilion of the Tang Dynasty, Yan Lide was the first person to fully understand the engineering blueprint for the manual water pressure pump.
This middle aged architect had originally served the doomed Sui dynasty before wisely switching sides and joining Li Shimin's inner circle.
He now held the prestigious position of Director of the Imperial Manufactory. For decades, Yan Lide had believed that the greatest achievement of his career would be designing a magnificent tomb for some future emperor.
Then the Light Screen flickered to life.
Yan Lide stared into the glowing box and witnessed a futuristic world built through the labor and ingenuity of ten million master craftsmen. In an instant, every royal tomb blueprint he had ever designed was abandoned.
His ambition now belonged to the living. He wanted to transform the Imperial Manufactory into a force capable of reshaping the Great Tang and turning it into a proper utopia for human life.
Yan Lide gasped so loudly that Emperor Li Shimin turned toward him.
The Emperor understood almost nothing about the device on the screen, but Yan Lide was already standing straighter.
"I can build a working prototype before sunset," the architect declared.
Li Shimin's spirits rose.
What did an emperor need more than anything? A broad mind and the ability to place the right genius in the right position. He did not need to understand the fluid dynamics of a mechanical pressure valve. He only needed Yan Lide to understand it.
Combined with the architect's earlier promise to tame the Yellow River, this new declaration earned him the Emperor's approval.
"Take your time," Li Shimin said with a smile. "Just show me the finished prototype tomorrow morning."
Watching the exchange, Yan Liben decided that he, too, deserved a share of this historical glory.
He turned toward the Emperor with an unmistakably hopeful expression, silently requesting permission to assist his elder brother.
Unfortunately, Dr. Sun Simiao noticed him first.
The imperial physician remembered how diligently Yan Liben had followed him during the past two months, sketching anatomical diagrams through one dissection after another. He gave the artist a kindly smile.
Yan Liben immediately looked away.
The Imperial Medical Academy had left him with memories he preferred not to revisit, especially the smell of decay, the sound of ribs being pried apart, and Sun Simiao's habit of correcting his sketches by making him measure organs directly inside an opened chest cavity.
He kept his eyes fixed on the floor.
Sun Simiao stroked his white beard. He had originally planned to give Yan Liben five extra days of paid leave on top of the standard ten day New Year holiday.
Seeing the young man's dedication, however, the doctor changed his mind.
Yan Liben was clearly just like his elder brother, a promising scholar willing to endure hardship for the sake of science.
Once the holiday ended, Sun Simiao would summon him to observe another surgical procedure.
Yan Liben remained unaware of this new arrangement.
As for the Light Screen's praise of ancient Chinese urban cluster planning, the elite ministers inside the Ganlu Pavilion were not particularly impressed.
The descendant on the screen had already confirmed that advanced city zoning existed as far back as the Shang and Zhou dynasties. Naturally, the brilliant people of the Qin, Han, and Tang dynasties could organize a few satellite towns.
That was hardly impressive.
After successfully lowering their expectations of the mythical Roman Empire, the Tang ministers leaned forward again. They were now eager to hear more geopolitical gossip about those foreigners.
Unfortunately, the future host had no intention of satisfying them.
The screen shifted back to the climate change graph covering the past two thousand years.
Lightscreen]
[Alright, let's shift our focus back to that climate change graph.
Civilization is not some puppet dancing on weather's strings. But anyone who denies climate's impact on human history is straight up lying to themselves. Once you realize how chaotic the weather actually was, the ancient Chinese people's endless struggle to survive becomes even more impressive.
That said, when we examine how dynasties actually rose and fell, climate change was clearly one of the biggest factors. Not the only factor, but a massive one.
The perfect textbook example was Emperor Yang of Sui.
His entire reign coincided with one of only three major temperature spikes in the last two thousand years of Chinese history. The first warm period forged the military machine of the Western Han Dynasty. The second helped the Yuan Dynasty build an empire that stretched across an entire continent.
Emperor Yang was standing on the ultimate historical tailwind.
He had every possible advantage. The climate was cooperating. The empire had resources. The historical momentum was practically carrying him uphill.
And what did he do with it?
He tripped, fell off a cliff, and smashed the entire Sui Empire into a million bloody pieces.
Even destiny itself looked at this man and decided it had done enough.
Fortunately for the Chinese people, Li Shimin showed up right on schedule.
He stepped onto the historical stage and immediately got to work. He swept outward to conquer the world, then swept inward to deal with his father and brothers. Without even stopping for a proper breath, he launched military campaigns to the west and north before building the golden age of Zhenguan.
Thanks to Li Shimin, China did not waste this once in a millennium climatic golden window.
That is why, when we analyze this warm period spanning the Sui and Tang dynasties, Li Shimin's personal contribution is practically irreplaceable. He was the ultimate example of humanity fighting back against nature.
And remember, struggle is not just about surviving freezing winters. It is also about recognizing a rare period of favorable conditions and grabbing the opportunity before it disappears.
Then came the part that really got people talking.
There was a trendy historical theory claiming that the Tang Dynasty conquered the world mainly because of Li Shimin's father, Li Yuan. Apparently, that argument falls apart under even the most basic scrutiny.
Rather than burying everyone under a mountain of academic papers, the program decided to explain the problem through a classic internet trope.
The body swap game.
What would actually happen if we forced Li Shimin to swap places with Zhu Qizhen, the Ming Dynasty emperor?
Alright, that wraps up this episode of The Climate Shifts of Han and Tang.
Smash that like button, hit subscribe so the algorithm does not lose you, and I will see you all right here at the same time next week!]
Li Shimin had been nodding along gracefully, happily accepting every word of praise.
Then the screen casually mentioned that he had eliminated his father and brothers.
The benevolent smile on the Emperor's face froze.
Inside the Ganlu Hall, the ministers immediately activated their emergency protocol. Every man in the room stared straight ahead at the Light Screen. No one spoke. No one turned his head. No one even seemed willing to let his neck move.
Fang Xuanling suddenly found the wood grain of his desk deeply fascinating. Wei Zheng became absorbed in the structural integrity of his teacup.
They were masters of the ancient art of selective deafness.
With the entire court pretending not to have heard anything, Li Shimin had no reasonable target for his anger. His chest rose and fell twice as he drew in a deep breath, then forced himself to swallow the outburst.
He endured it.
Then the screen used the word irreplaceable.
That single word did more to repair his mood than any apology could have. The Emperor's furious expression softened, and a broad smile soon returned to his face.
So what if these future descendants occasionally took a few liberties with his family history? They still recognized the true scale of his achievements.
The tension in the Ganlu Hall vanished almost immediately.
Li Shimin cleared his throat and asked, "Who is this Zhu Qizhen?"
As for the screen's casual dismissal of Li Yuan's historical legacy, the Emperor decided to remove that part from his memory.
His father was safely residing in another palace. Besides, the ancient Book of Rites had already made the matter clear. A father should not boast about his son's virtues, and a son certainly had no business discussing his father's mistakes.
Chancellor Du Ruhui coughed into his fist, quietly grateful that the Emperor had chosen to let the matter pass.
When Li Shimin asked his question, Du Ruhui answered at once.
"The future descendant mentioned that name earlier. Zhu Qizhen was said to be another emperor as disastrous as that coward Zhao Gou."
Li Shimin did not need much imagination to understand what sort of ruler they were discussing.
Fortunately, the Light Screen had no intention of making him wait.
A flood of floating text suddenly filled the display, answering his question directly through the Server Chat Log.
[Server Chat Log]
[History_Nerd_99: Holy crap. If Li Erfeng magically teleported into Zhu Qizhen's throne, he would absolutely lose his mind with joy. He would inherit the infinite wealth of the Yongle and Xuande golden ages, plus a fully equipped standing army of half a million elite imperial guards. Li Erfeng would literally not know how to lose a battle with those cheat codes enabled.
Leaf_Fanboy: And if Zhu Qizhen swapped into Li Shimin's body during the founding of the Tang, the rebel warlords Dou Jiande, Wang Shichong, and Li Mi would be throwing huge parties. They would be screaming that their time had finally come.
Ant Walk_Crafter: Honestly, this body swap theory is incredibly wild, but it perfectly highlights exactly why Li Shimin is a God of War. Without this absolute God of War carrying the entire team on his back, the Tang dynasty never survives long enough to reach the Xuanwu Gate drama. If Li Jiancheng looked at Zhu Qizhen aggressively, Zhu Qizhen would surrender on the spot.
River Stone_Scholar: Hold on, which God of War are we talking about here? Are you disrespecting Zhu Qizhen? He is the ultimate God of War for the Mongol leader Esen! The man literally handed the Mongols a masterclass on how to get your entire army captured.
Iam Lazy_Police: Give me a break. Without Li Erfeng they would have hit a game over screen the very first time they tried to choreograph the Prince of Qin Shattering the Formation military dance. With Zhu Qizhen's abysmal baseline stats, it is highly debatable if he could earn the title Prince of Qin in the first place.
Armchair_Cheap: If those two swapped places, their brains would short circuit trying to understand each other. General Li Shimin would scream, asking how the hell you get captured while commanding half a million troops. And God of War Zhu Qizhen would scream back, asking how the hell you dare charge an army of one hundred thousand using only three thousand cavalry.
March If_get Paid: I am telling you right now, playing on Zhu Qizhen's easy mode script means you do not need a genius like Li Shimin. You place any random person in there, and they could run the empire flawlessly. When there is a foreign crisis, you ask Minister Yu Qian. When there is a domestic crisis, you ask Minister Yu Qian. You sit comfortably in the harem drinking wine while history records you as a legendary sage king.
Qinwang_Pozhen_Enjoyer: The Prince of Qin Shattering the Formation is not just a dance, it is the ultimate proof of military supremacy. Li Shimin personally choreographed it with a hundred and twenty armored cavalrymen. Zhu Qizhen would probably trip over his own ceremonial robe before the first drumbeat.
Fake_Historian: People always forget that Li Shimin was not just a general. He was a functioning emperor who understood logistics, taxation, and diplomacy. Zhu Qizhen could not even understand the basic concept of not trusting a eunuch with the entire army. The gap is not a gap. It is a canyon.
RIP_Rhinos: Can we talk about how the streamer casually dropped that the entire Ming army got captured because one guy panicked? Half a million soldiers. Gone. Because one emperor wanted to play hero. I am physically ill.
History_Teacher Wang: This is why I tell my students to stop romanticizing imperial power. The difference between a golden age and a national catastrophe is often just one man sitting on a throne.]