317.
A Northern Wind from the West
A north wind blew from the west.
At its edge clung the stench of iron and dust.
Word had already arrived two days earlier by courier:
Xu Da, Zhu Yuanzhang's grand commander, was marching south.
On the day he heard the news, Park Seong-jin set his brush aside
and slowly unfolded the map.
"As expected," he said.
That was all.
Natural Stronghold — Tianxian (天險)
From that day on, the land around Chizhou began to change.
Discarded timber along the river was gathered and driven into stakes.
Burned ships were hauled in and bound together to form pontoon traps and false crossings.
Earth was mixed with lime to raise embankments;
beneath them, pine resin and oil were packed thick.
To the east of the city lay a shallow marsh.
Night after night soldiers hurled stones and overturned mud there.
The surface looked like moving water,
but beneath it iron hooks and spikes lay densely hidden.
"Leave paths for withdrawal at all times.
The instant the enemy steps in, cut those paths."
Park Seong-jin's orders were precise.
It was a system that turned attack and defense together,
a living mechanism rather than a static wall.
Each night he climbed the battlements and watched the river.
Whenever the wind shifted or the grain of the water changed,
he adjusted troop placements by small degrees.
General Zhao Dao of Chen Youliang's forces asked beside him,
"General, this is no longer a fortress—it's a trap."
Park answered,
"This is the cutting edge of a natural stronghold.
One piece of difficult terrain does the work of ten soldiers."
In ten days, the fields around Chizhou were transformed.
On the surface they appeared flat,
but beneath every blade of grass and every pool of water
waited steel and fire.
The river's depth was altered.
Straw mats floating atop it were ready to swallow any footstep.
Soldiers dug shallow trenches along the banks,
covered them with thin soil and grass—
careful work, invisible to the untrained eye.
At dawn, Park walked the lines with the men.
At every step he touched the ground with his fingertips,
issued orders, and confirmed them himself.
Where he passed, the cold of war settled into the earth.
This was why Goryeo had endured for a thousand years
while fighting forces many times its size.
Victory alone was not enough—
the exchange ratio had to be overwhelming.
For one Goryeo soldier lost, twenty enemy soldiers must die,
or the state would not survive.
One condition for such an exchange was defensive engineering.
Their fortifications were different from the foundation up;
the variety and quality of weapons laid before them
defied imagination.
They had already proven this—on a smaller scale—
many times at Hwajuseong.
An army without battle is an army at labor.
That, too, was a Goryeo axiom.
For one Goryeo soldier to kill hundreds was not glory—
it was necessity.
Turning Chizhou into a Natural Fortress
The fields below the city woke, shaking off dawn mist.
The scent of char and wet soil mingled in the air
as soldiers were already in motion.
From the battlements, Park surveyed the ground.
Tracing the river's flow with his finger, he spoke.
Scouts circled the city, marking approach routes and hidden waterways.
Park designated three friendly corridors with wooden stakes,
each marked by strips of white cloth—
safe passages for civilians and supply lines.
Moats and Marshes — Blocking Paths with Water
Canals linking the river and approaches were dammed with earth,
diverting the flow.
Shallow wetlands were left intentionally
to mire enemy formations.
Burned ships were dragged in and partially locked in place,
covered with rotting planks to resemble solid ground.
The moment the enemy crossed, the rear would be severed.
As soldiers dug with spades and forks, Park calculated the tides.
"When the water turns,
that pit closes before it can be seen."
Hidden Pits — Ground That Looks Open
Approach surfaces were leveled,
then covered with thin soil and dry hay.
Beneath stood stakes and antler-wood spikes.
Each pit was marked by coded signs
so friendly troops could pass safely.
At night, smoke screens swallowed torchlight.
Park stepped onto one pit himself and said,
"The enemy's feet hurry the heart.
We simply remove that haste."
Hammer Tunnels — Guided Corridors of Death
Shallow tunnels were dug beneath the fields,
branching into guided routes.
Once the enemy committed to a path,
ropes were cut from within, traps opened,
and ambush units poured in.
Entrances were planked to look like open ground.
Inside were pull-frames and rockfall cords.
Tunnel crews trained under moonlight,
moving without sound.
Antler Fields
Thorn stakes were driven thick before moats and approaches
to halt cavalry.
Iron caltrops were scattered on wheeled access paths.
Expected charge routes were seeded with iron-spiked horse traps.
Friendly routes were clearly marked with stakes and white cloth.
Wall Defense — Weights, Logs, and Falling Stone
Pulley systems bearing stones and iron weights
were installed along the battlements.
At the approach of siege engines or massed troops,
they would be dropped at once.
Felled logs were prepared near the gates
to collapse clustered attackers.
Drop zones and friendly safety lines
were confirmed three times.
"When the weights fall,
our path must remain open. Understood?"
Ranged Fire and Anti-Assault Measures
Continuous firing positions lined the riverbank and walls.
Catapults targeted ships and rams;
crossbows and longbows targeted dense formations.
Archers memorized signals:
two red cloths—concentrated fire;
one white—withdrawal.
Four cauldrons of boiling water were placed near the walls.
Oil and firepots were stockpiled sparingly.
Large kettles were lashed near the gates for immediate release.
Nets, Double Gates, and Reserves
Cast nets and barbed nets were set beneath bridges, gates, and docks.
Enemy ships would be snared the moment they touched.
Behind the gates, double barricades were raised—
even if the first fell, the second would hold.
Reserves were stationed across the river
so withdrawal would be tactical, not a rout.
Signals and Psychological Warfare
Twenty-four beacon posts and watch stations were established.
Smoke, drums, and fire signals were shortened to prevent confusion.
Scarecrows and wood piles drew enemy eyes.
Proclamations and rumors written by Yoon Dam
were spread to sap morale.
Friendly routes were marked by white cloth
and specific stone patterns.
From the battlements, Park lowered his voice.
"The enemy always chooses the path that looks most open.
We design that openness.
The river is on our side.
The land is our shield.
A trap is one device of the Way."
He looked down at the river.
"I wish to avoid battle.
But before it comes, we must buy time.
Once the enemy is caught, encircle immediately.
Capture first; minimize killing.
White cloth marks friendly paths.
Anyone who loses the mark is taken prisoner."
The soldiers raised their hands as one.
Mud, blood, and sweat clung to their skin.
The dawn wind cut across the river.
Chizhou was no longer merely a city.
It was a vast trap, completed in Park Seong-jin's mind.
A fortress is not made simply by water and walls.
He had turned one city into a natural stronghold—
and even if it fell,
the enemy would lose an army in exchange.