[Lightscreen]
[The Five-Fang Tower Warship—known in later generations as the Sui Five-Fang Battleship.
This type of tower ship first appeared during the Sui Dynasty. It was called "Five-Fang" because it had five stacked decks, like a mobile apartment building with anger issues.
The ship was about fifty-five meters long, fifteen meters wide, with a draft of just over two meters. From keel to rooftop lookout, it stood more than thirty meters tall.
A proper ancient Chinese warship.
The top deck served as the observation and command tower.
The lower four decks were packed with soldiers.
Back in Sui times, threats at sea were limited. Most enemies used small boats, which meant the Five-Fang's original design focused on bullying light targets.
Every deck had parapets and arrow slits, allowing archers to rain death downward. But against enemy ships, the real star of the show was something called the paigan.
The concept was brutally simple.
Imagine a giant mast with a massive stone hanging from it.
When battle began—release rope.
Gravity handled the rest.
The stone slammed straight down, smashing enemy ships like rotten melons. Afterward, soldiers on deck cranked the winch, pulled the stone back up using pulleys, aimed again, and—
SMASH.
The earliest Five-Fang ships mounted six paigan rigs—front, back, left, and right. In combat, they charged directly into enemy formations and unleashed a full rotation of overhead smiting.
Six hits.
Nonstop.
On repeat.
According to legend, the power was "unmatched."
Picture it: a giant floating insect stomping through a fleet.
Honestly? Kind of adorable.
When the Tang Dynasty inherited this ship design, someone looked at all that empty deck space and thought—
What a waste.
So they slapped on giant crossbows, stone-throwing machines, and other battlefield monstrosities. At that point, the Five-Fang officially earned the title of capital ship.
Records show that as early as the late Warring States period, China already had repeating crossbows, though they required multiple people to wind them.
The Han Dynasty later introduced the bed crossbow.
No finesse.
Just raw violence.
The Tang artisans then combined the two ideas, improving the Han bed crossbow's single bow arm into multiple arms.
Thus was born the Tang windlass crossbow.
Mounted on wheeled frames, movable at will, tensioned by winches—this thing featured seven firing channels: one main bolt and six auxiliary bolts.
Pull the trigger.
Seven bolts launched at once.
Effective range: seven hundred Tang paces.
One Tang pace was about 1.55 meters.
That meant roughly one kilometer of "you're definitely not okay."
Compared to this monster, Tang trebuchets were… modest.
They still used traditional traction-style designs—basically a big lever. One end held the stone, the other end had people pulling like their lives depended on it.
Efficiency? Low.
Cost? Cheap.
Add Tang fire arrows to the mix, and against the Wa forces, it was nothing short of dimensional suppression.
Winning was inevitable.
Unfortunately, when the Song Dynasty inherited these technologies, they mostly focused on refinements rather than true innovation.
The Eight-Ox Crossbow extended range by about five hundred meters.
Trebuchets got heavier stones.
The so-called pinnacle—the Seven-Arm Cannon—required over two hundred men to operate and could throw a sixty-four-kilogram stone about a hundred meters.
The energy loss alone could make an engineer cry.
Practicality? Questionable.
Then the Mongols casually hired craftsmen from West Asia, tweaked the design, and—
Boom.
The Huihui trebuchet smashed Xiangyang to rubble and ended the Southern Song.
Ironically, this counterweight trebuchet wasn't even new in the West. It was a hybrid design from Arab engineers.
And that's not even mentioning torsion engines, which already existed there.
True revolution?
That came with the Ming.
They stopped throwing stones and started throwing explosions—
abandoning counterweights and ropes in favor of cannon and gunpowder.]
In the imperial garden of Bianliang, Zhao Kuangyin's expression was grim.
Squatting on the ground, he used a small jade axe as a stylus, sketching the outline of a Huihui trebuchet in the dirt.
He stared at it for a few breaths.
Then stood up.
And casually erased the entire thing with his foot.
Zhao Guangyi, standing nearby, quickly wiped his face into something resembling sincerity.
"Brother," he said earnestly, "I request to take charge of the Directorate of Works and share your burdens!"
Zhao Kuangyin looked at him.
After a pause, he placed a hand on his brother's shoulder.
"Your heart is in the right place," he said calmly.
"But you only recognize the drawing. You understand nothing of construction or craftsmen. What good would it do to send you?"
Zhao Guangyi lowered his head slightly, eyes drifting to the jade axe still clutched in his brother's hand.
He wisely said nothing more.
Zhao Kuangyin returned to his stone seat, a thought slowly forming.
One skill builds nations. One skill breaks cities.
Perhaps merchants trading with foreign peoples should be strictly forbidden from transporting craftsmen or manufacturing techniques.
And…
He should probably take another good look and memorize this so-called torsion—what was it—trebuchet.
Relying on memory alone felt risky. Better summon some palace eunuchs skilled in drawing.
As for his brother?
Zhao Kuangyin had no expectations.
He knew exactly what his little brother was capable of.
In contrast, Kongming was in high spirits inside the Chengdu prefectural office.
With nothing but a charcoal pencil, he now recreated diagrams from the future so precisely that Pang Tong watched with open envy.
Kongming had always been frighteningly versatile.
Back in Nanyang, Pang Tong had seen him copy calligraphy, play the qin, paint landscapes—and on hot days, casually swim laps in the river.
Even then, Pang Tong had wondered if Kongming's stamina had a limit.
Now he watched as Kongming produced a flattened stone strip, aligned it against the paper, and in a few swift strokes recreated a torsion trebuchet diagram perfectly.
Then—leisurely—he switched to a brush, dipped it in ink, and neatly wrote:
"Torsion Trebuchet."
Pang Tong felt something twist in his chest.
"Kongming," Pang Tong said after steadying himself, "what do you think of this thing?"
Pang Tong studied the diagram carefully.
"The power depends entirely on the quality of the twisted ropes."
He pondered.
"Even using coarse hemp would be difficult."
"And compared to traction trebuchets…" He tapped the paper. "Each has its strengths."
"The traction type is easy to build and operate. A few iron parts, three to five soldiers, and it's ready in fifteen minutes."
"This western design is more refined, but difficult to transport. And for the torsion ropes to work properly, they'd need sinew or adhesive cords."
Ever since Gong'an County embraced engineering, they'd learned one painful truth:
Some machines required materials that were soft yet resilient—very much like animal sinew.
Kongming and his wife had experimented extensively, eventually settling on peach resin as a substitute.
But peach resin was rare.
And expensive.
Sighing, Kongming smiled.
"I wonder how the West solved this."
As for the paigan?
Everyone in Chengdu understood it at a glance.
Water-powered workshops across the land already used pulleys and gears. Gong'an even had a dedicated gear workshop producing bronze and iron components.
That inspired Kongming with several improvements to the paigan, which he planned to sketch and send back to Jingzhou.
The paigan had limitations—but like traction trebuchets, its greatest virtue was simplicity.
Cheap. Durable. Easy to build.
The ship-mounted giant crossbows were like torsion trebuchets—
Powerful.
Expensive.
Maintenance-hungry.
Thinking this through, one word surfaced in Kongming's mind:
Productivity.
No matter how powerful a weapon was, it meant nothing if it couldn't be produced at scale.
Just like armored cavalry—devastating, but impossible to mass-produce with current output.
The torsion trebuchet suffered from the same flaw.
One small rope brought everything to a halt.
Materials science was only just beginning.
When would they find a true replacement for sinew and peach resin?
Kongming gained a new worry.
In the Ganlu Hall, Yan Lide and Yan Liben were practically vibrating with excitement.
This thing would be immensely useful for the Tang—and Yan Lide was a master of such matters.
He had never felt so relaxed serving as Director of Works.
Stronger armor.
Better horse gear.
Superior warships.
Deadlier weapons.
Future-era craftsmanship concepts.
Improved drawing techniques.
Advanced architecture.
Every day felt like opening treasure chests.
And most importantly—
While generals fought tooth and nail, and civil officials crowded the court—
The path of craftsmanship had only two people.
The Yan brothers.
They had once planned to let their sons enter officialdom through privilege.
Now?
Forget that.
Learn drafting.
Learn engineering.
Become master craftsmen.
In today's Tang—
That was real power.
Li Shimin stood before a map of Liaodong and the Korean Peninsula, breathing deeply.
As a commander, he understood clearly:
With these new cannon designs, Liaodong's cities would no longer slow Tang armies.
Goguryeo could fall at any moment.
The peninsula was within reach.
But after conquest—
How would Tang ensure it remained loyal for generations?
Since he had a choice, Li Shimin wanted to eliminate future troubles entirely.
The scenes on the heavenly screen were lessons written in blood.
Unchecked troops sowed resentment in Baekje. Even though Liu Rengui later crushed rebellions through force, Li Shimin saw no true resolution.
Suppressed contradictions always resurfaced.
He'd learned that watching his own mishandling of the Eastern Turks.
And Goguryeo?
From Guangshen's era to Li Shiji's campaign of annihilation—
Decades of warfare.
Hundreds of battles.
Hatred ran deep.
How could that possibly be resolved?
Thus, Li Shimin held a grim outlook on Tang governance in Liaodong.
As for Silla?
Tang had practically cleared the peninsula for them.
Thoughts churned.
Compared to the steppe tribes, Liaodong was less wealthy, less martial—
But its internal contradictions were ten times more complex.
Expanding borders was easy.
Building an eternal Chinese realm?
That was hard.
Then—
Li Shimin smiled.
Precisely because it is hard…
I must do it.
[Lightscreen]
[At the Battle of Baekgang, Liu Rengui crushed the Wa forces not only because of superior equipment—
But because of knowledge.
The Wa fleet didn't launch their boarding charge on a whim.
According to their own records, they observed the skies and believed the wind favored them.
"With the wind at our backs," they reasoned,
"the Tang ships cannot advance. Even if their hulls are strong, they cannot move. What is there to fear?"
What they couldn't understand was—
Why Tang ships advanced against the wind.
And then surrounded them.
The answer was simple.
By adjusting hull and sail angles between 35 and 45 degrees, ships could zigzag forward—sailing into the wind.
Wind flowing over curved sails created pressure differences, generating forward force.
Later generations would call this the Bernoulli effect.
High school physics explained it clearly.
But Tang sailors didn't need equations.
They had experience.
The Wa understood neither theory nor practice.
So Tang ships encircled them from upwind positions and fired fire arrows with impunity.
Total annihilation.
Strip away the battle's surface, and the truth was clear:
From social systems to soldier quality, from craftsmanship to knowledge—
The gap was comprehensive.
Baekgang was a victory of civilization level.
Yet thinking of Tang naval glory inevitably brought regret—
China's absence during the Age of Sail.
Some claimed the compass invited pirates.
That wasn't entirely wrong.
But also not entirely right.
Civilization and science were chains of countless low-probability events.
Consider this:
Around 300 BCE, Elements established axiomatic thinking in geometry.
Did Western science immediately explode?
No.
Progress remained slow.
It was the Arab Empire that truly advanced mathematics.
After the fall of Sassanid Persia, Arab rule stretched into Central Asia, blending Eastern and Western knowledge over centuries of peace.
Papermaking from the East.
Greek geometry from the West.
Indian astronomy.
These combined into a golden age, which later flowed back into Europe.
Paired with transparent lenses in the 11th century, geometry and optics matured—eventually birthing the Renaissance.
Still—
East and West were merely different paths.
The real gap appeared when the West produced its own Confucius of science.
The Apple Heavenly Venerable.
Sir Isaac Newton.
Among his many achievements, his work on sextant theory allowed the British Navy to create the octant.
For the first time, humanity could determine position at sea without relying on stars or coastlines.
True oceanic navigation began.
And only then did the East truly fall behind.
The compass?
Just one small piece of the puzzle.
…This limitation had been apparent for a long time.
But now—
it finally seemed to have a solution.
What the later generations called "science" did not begin with craftsmanship,
nor with inspiration,
nor even with talent.
It began with agreement.
Agreement on what could be accepted without proof.
These were called axioms.
From axioms, scholars established postulates—conditions assumed to be true within a defined scope.
And from axioms and postulates, through strict reasoning, they derived theorems.
This entire process was governed by a method known as logic.
Logic did not create knowledge.
It merely ensured that once a starting point was chosen, every conclusion that followed could be examined, replicated, and verified by anyone who understood the rules.
Thus, knowledge ceased to be the inheritance of a few gifted minds— and became something that could be taught, copied, corrected, and accumulated.
Only with such a method could later generations construct lenses, engines, ships, and weapons that surpassed imagination.
Otherwise, even if blueprints were handed down from heaven, they would remain nothing more than drawings.]