[Lightscreen]
[The so-called Malthusian Trap is, in essence, part of the grand cycle laws of history.
Put simply, it is the contradiction between infinite exponential growth and finite resource growth—the conflict between the infinite and the finite.
From a macro perspective, ever since the origin of life, algae and plants experienced exponential expansion, rapidly consuming carbon dioxide in the atmosphere, altering oxygen levels, and triggering mass extinctions and ice ages. None of this escaped the Malthusian Trap.
From a historical angle, the evolution and migration of early humans, the repeated rise and collapse of feudal dynasties, and later the Industrial Revolution—all of their internal driving forces are clear enough. At the root, they are still conflicts between population growth and means of production.
Even on the microscopic scale, the intensity of microbial survival wars is no weaker than that of humanity. Antibiotics can be regarded as the ultimate killing weapons evolved in microorganisms' own wars.
The Malthusian Trap is a shackle engraved into the genes of all living beings. Yet evolution itself is born from this shackle—and so are feudal dynasties.
The founding of the Tang Dynasty was, in essence, a temporary escape from this trap. The price was the massive population loss caused by decades of warfare from Northern Wei through early Tang, along with the large-scale demographic destruction wrought by powerful elites.
The enormous amount of unclaimed land freed by population collapse was naturally reclaimed by the state. Using this as capital, early Tang successfully implemented the Equal-Field System and the Rent-Tax-Labor System, laying the foundation for Tang prosperity.
Wa (Japan), however, was different. Although the Taika Reform did strengthen national power, the Wa central authority traded political privileges to aristocratic clans in exchange for only part of their land, implementing the Handen-Shūju system adapted from the Equal-Field Law.
Moreover, the Taika Reform also allocated land to aristocrats' slaves. Since aristocratic clans already possessed large numbers of slaves, they naturally did not oppose the reform. These slaves nominally held land, but in essence farmed on behalf of their masters.
Thus, even today, Japanese scholars still believe that post-Taika Japan never truly entered feudal society, but rather represented a distorted continuation of slave society.
In the Tang–Wa conflict, one side was a fully developed feudal empire; the other was a malformed slave society.
The Tang victory, therefore, can only be called inevitable. There was simply no reasonable way for Tang to lose.
The real pity is that afterward, whenever Chinese feudal dynasties clawed their way out of the trap, their political evolution always moved toward three directions: prioritizing agriculture while suppressing commerce, rectifying officialdom, and strengthening imperial power—endlessly grinding within the smallholder economy.
The result was missing the very tools that could solve the Malthusian Trap on a global scale.
For example, isn't Champa rice—'from planting to harvest in just over fifty days'—fragrant enough?
Or corn from the Americas—doesn't that count as miraculous?
When making this episode, Zhangyu UP got curious and checked.
The current world records:
Wheat's highest yield per mu is 1,042 kilograms.
Rice's highest yield per mu is 1,149 kilograms.
Corn is truly heavyweight—its highest yield per mu reaches 2,576 kilograms.
To ancient people, this would be nothing short of myth.]
The later-era unit "kilogram" was not unfamiliar to Kongming and the others.
After all, the earlier gift of horseshoe gold had already involved conversions between contemporary and later weight units.
Thus, the calculations themselves were not complicated.
Liu Bei did a rough estimate in his mind and immediately felt deep agreement with what the descendant had said.
"Rice… thirty-eight shi per mu?"
Liu Bei's eyes nearly fell out of their sockets.
He remembered clearly that last year, even the most fertile field on the Chengdu Plain—paired with composting methods—produced only three shi and five dou per mu.
The gap exceeded tenfold.
The comparison was simply too brutal.
Compared to this, talk of traps and Wa instantly flew out of Liu Bei's mind, completely unworthy of attention.
After all—
"Could this corn truly be made of jade beans?"
"Eighty-five shi per mu?!"
Zhang Fei cried out in shock.
Still unwilling to believe his own calculations, he recalculated them again. After confirming they were correct, the brush in his hand snapped and clattered to the floor, his expression finally losing all control.
Like his elder brother, Zhang Fei was well-versed in farming matters. That was precisely why this terrifying yield struck him so deeply.
By contrast, Kongming remained much calmer, even having the leisure to sigh to Liu Ba and Pang Tong beside him.
"Champa rice and corn are both results, not causes."
"If one were to promote maritime policy, without the sextant that appears over a thousand years later, ocean voyages would rely heavily on astronomy."
"To observe the heavens requires the study of mathematics.
To study mathematics, science naturally arises.
Only then does one reach what the descendant spoke of earlier—science and technology are the primary productive forces."
Pang Tong nodded.
If later generations could ascend to the heavens, comprehend the vastness of heaven and earth, roam the void, and observe the mysteries of the cosmos, then achieving such results in farming was—if not astonishing—at least unsurprising.
After agreeing, he and Kongming once again marveled at the breadth of later generations' horizons.
"Observing the cosmos above, probing the netherworld below;
knowing humanity's origins in the past, explaining the rise and fall of dynasties in the future—
what later generations see is truly beyond the human realm."
Because of this, Kongming's desire for scholarship grew ever more urgent.
He carefully copied everything he had seen, intending to ponder it thoroughly in his spare time. Meanwhile, Pang Tong noticed a particularly gripping term.
"Grand historical cycle law?"
After hearing the descendant's explanation, Pang Tong felt he vaguely understood something—yet not fully. It was as though he were viewing flowers through mist.
Kongming remained silent. As he wrote, he spoke slowly.
"In the second year of Zhongyuan, our Han had four million households.
By the third year of Yongshou, the populace had reached ten million households.
Exactly one hundred years apart—the population more than doubled."
"Yet farmland yield per mu increased by less than half a shi over that same century."
On the white paper, Kongming listed only two sets of numbers: household count and yield per mu.
At this moment, he felt ever more keenly that mathematics was truly useful.
After being enlightened by later generations, with just these two sets of numbers, Kongming seemed to see a towering structure on the brink of collapse.
Liu Bei also understood upon hearing this, staring at the numbers in silence.
"Yields are hard to increase. But if we fully open all cultivable land—no, impossible!"
He immediately rejected the idea, his expression turning bitter.
"Powerful clans annex land, corrupt officials run rampant.
The more people there are, the less land the people have.
When the people lose their land, how could chaos not arise?"
Before the Battle of Red Cliffs, if asked why the realm was in turmoil, Liu Bei could rattle off a long list of names.
A Son of Heaven losing authority,
treacherous eunuchs ruining the state,
Zhang Jiao raising rebellion,
Dong Zhuo abusing power,
and Cao the traitor holding the emperor hostage.
But now, having seen more, when he thought of the same question again, those names were gradually crossed out in his heart.
Especially Zhang Jiao—what wrong had he committed?
If the Han would not let him live, was he supposed to quietly go die?
Chaos had never been the fault of any single person.
Clapping his hands, Liu Bei was the first to rouse everyone from the heavy atmosphere.
"A man born into this world must open an age of peace!"
"Now that we know the principles of later generations, capable of ordering a century of chaos, there is no reason to hand the realm over to Cao the traitor!"
"The urgent task is this: seize Guanzhong in the north, urge Wu Yi in the south, stabilize Nanzhong quickly—then dispatch elite guards to obtain Champa rice seeds!"
Everyone was familiar with the lands of the Indochinese Peninsula. Wasn't it just south of Jiaozhou?
The Shendu route even had a branch leading there. Securing this rice that ripened in fifty days was what truly needed to be done at once.
…
In the Ganlu Hall, Li Shimin was likewise a man of practical temperament.
"Issue an edict to the Protectorate of Annan: present Champa rice seeds."
"If they do not offer them to Tang, I shall personally take them!"
No one in the hall advised restraint—not even Wei Zheng.
Because rice that ripened in fifty days was simply too astonishing.
By comparison, how long did Tang rice currently take from planting to harvest?
Over one hundred and twenty days.
Wei Zheng understood this as well. This was something that truly deserved to be called an auspicious sign.
Not only did he refrain from advising the emperor to temper his urgency—he even felt like advising him further:
Waiting for voluntary tribute might take who knows how long.
Better to dispatch Tang elites to obtain it directly.
But thinking of the miasma-ridden Lingnan roads and their treacherous terrain, he ultimately let it go.
He could only hope that the natives of Annan were sensible enough—remember how the Eastern Turks were destroyed—and obediently present the seeds, avoiding unnecessary trouble.
After settling the matter of Champa rice, Li Shimin immediately asked:
"Where is the Americas?"
This was the first time Li Shimin had heard the name "Americas."
From later generations' descriptions, it seemed to be a vast landmass containing unknown empires.
Tang lay in Asia.
Rome lay in Europe.
Then where was the Americas?
Li Shimin was puzzled.
Thus, everyone in the hall shifted their gaze to the right, where two massive maps hung.
One was a detailed map, stretching from Rome in the west to Wa in the east, from the northern desert to the Malacca Strait—depicting only a portion of the world, with nothing known beyond.
The other was an outline of the globe. When it had appeared on the light screen, the Earth had slowly rotated—but before completing even one full turn, it had vanished. Only part had been seen.
Now they only knew that south of Europe lay a vast landmass; southeast of Tang, beyond a sea of islands, lay another; and traveling east from Liaodong also seemed to reach a sizable land.
Thus Li Shimin asked directly:
"Is this Americas south of Europe, or southeast of Tang?"
Du Ruhui pondered for a moment and replied:
"If the descendant says no living being can escape this trap, then perhaps the West escaped it with corn."
"But he also said corn requires seafaring to obtain. Thus, the Americas may lie southeast of Tang—or perhaps… on the far side of this globe."
The reasoning was sound.
Thus, Li Shimin could only temporarily extinguish his curiosity.
He casually asked instead:
"In later generations, how many kilograms equal one shi?"
He wanted to compare later-era yields with Tang's.
The ministers exchanged glances. How was this calculated?
Then Fang Xuanling stepped forward. He recalled that when later generations spoke of that "magical Book of Jin," they had casually mentioned that 1,500 jin of the Jin era equaled a bit over 300 kilograms.
Using that conversion, one could calculate.
Du Ruhui chuckled inwardly—clearly, the descendant's disparagement of the Book of Jin had left quite an impression on his old friend.
Fang Xuanling, unbothered, quickly finished the math.
"Wheat yields twenty shi per mu.
Rice, twenty-one and a half.
Corn… forty-eight and a half shi per mu."
Li Shimin changed his mind instantly.
"We must prepare a fleet and open the seas for Tang!"