The news of the liquid stone spread through the province faster than the floodwaters ever could. Li Chen did not have time to enjoy his small victory in the courtyard. He knew that in engineering, a small sample in a bowl was one thing, but a massive structure in the real world was another beast entirely. The cement worked, but now he had to prove it could carry the weight of an empire.
He stood at the edge of the Broken Gorge. This was where the main trade road to the capital had been cut off for nearly a year. The old bridge had been made of heavy cedar beams, a beautiful structure that had simply snapped like a toothpick when the mountain runoff got too high. Now, there was nothing but a fifty foot gap and a dangerous, churning stream below.
Governor Wang stood beside him, tucked into a thick fur cloak to ward off the damp air. He was looking at the gap with a sour expression. "Prince Lu, I have given you the men and the stone you asked for. But you say you can cross this gap without a single forest of timber? The Imperial Architects say a bridge this wide requires pillars in the center, but the current here is too fast for stones to sit."
Li Chen looked down at the water. The Governor was right about the current, but he was thinking in the past. "I don't need pillars in the center, Governor. Pillars in the water are just targets for the river to hit. We are going to build a single span. We are going to use the strength of the earth itself to hold the road in the air."
The Governor laughed, a short, sharp sound. "A single span of fifty feet? Even the Emperor's best builders wouldn't dare. The weight of the stone would pull the whole thing down."
"It would if it were just stone," Li Chen said, turning to Lao, who was waiting with a group of smiths. "Lao, show the Governor what we have been doing at the forge."
Lao stepped forward, holding a long, thick rod of wrought iron. It wasn't the refined steel Li Chen missed from his old life, but it was tough, and it had the one quality he needed: tensile strength.
"Stone is good at being pressed down," Li Chen explained, his voice becoming calm and teacher like. "But stone is bad at being pulled apart. When a bridge bends, the bottom of it is being pulled. That is why stones crack. But iron? Iron loves to be pulled. We are going to put the iron inside the stone. The iron will handle the pulling, and the stone will handle the pressing."
The Governor stared at the iron rod as if it were a strange snake. "You want to hide metal inside the rock? That is madness. The metal will rust. The stone will reject it."
"Not if the stone is my cement," Li Chen replied. "My stone doesn't just sit on top of things. It bonds to them. It seals the iron away from the air and the water. They become one body."
For the next week, the Broken Gorge became a massive construction site. Li Chen did not start by building the bridge itself. Instead, he started with the foundations. He made the men dig deep into the solid rock on both sides of the gorge. He didn't want the bridge to just sit on the dirt; he wanted it anchored into the bones of the mountain.
He spent his days in the mud, personally supervising the mixing of the concrete. He was obsessed with the ratio. If there was too much water, the concrete would be weak and porous. If there was too little, it wouldn't flow around the iron rods. He used a wooden bucket with a small hole in it to measure the flow, a primitive version of a slump test.
"More sand!" he would shout, his voice echoing off the canyon walls. "The mix is too thin! We are building a road, not a soup!"
The workers were exhausted, but they were also curious. They had never seen a man work like this. Li Chen didn't sit in a tent drinking tea. He ate the same coarse bread they did, and he slept in a small hut near the edge of the cliff. He was a Prince by blood, but he was a foreman by choice. They began to call him the Iron Prince, a name that carried more respect than his royal title ever had.
The most difficult part was the formwork. To hold the wet concrete in place while it hardened, Li Chen needed a massive wooden frame. He used the last of the salvageable timber from the old bridge to create a curved support that spanned the gap. It looked like a giant ribcage hanging over the water.
"Once the stone is dry, we will pull the wood away," Li Chen explained to a skeptical Builder Zhou.
"And the stone will stay in the air?" Zhou asked, scratching his head. "By itself? Without the wood to hold it up?"
"The shape of the arch will push the weight into the mountain walls," Li Chen said. "It is the geometry of the circle. The more weight you put on it, the tighter the stones press together. It becomes stronger as it gets heavier."
Then came the day of the Great Pour. Li Chen had organized the men into a human chain. On one side of the gorge, dozens of large clay pots were being filled with the grey concrete mix. The men passed the pots from hand to hand, pouring the liquid stone into the wooden formwork where the iron rods had already been laid out in a complex grid.
Li Chen stood in the center of the wooden frame, suspended over the rushing water. He held a long wooden pole, using it to vibrate the wet concrete as it was poured. He had to make sure there were no air bubbles trapped inside. An air bubble was a weak point, a place where a crack could start.
"Keep it moving!" he yelled, his face slick with sweat and grey dust. "Don't let the layers dry! It must be one single piece of stone from one side to the other!"
The work went on for eighteen hours without a break. The sun went down, and they worked by the light of massive bonfires. Li Chen's arms felt like lead. His back was a wall of fire. But he didn't stop until the very last bucket was emptied and the surface of the bridge was smoothed out.
When it was finished, the bridge looked like a long, grey ribbon stretching across the dark gorge. It was quiet, the only sound being the rush of the water far below.
"Now," Li Chen said to the assembled men, his voice barely a whisper. "We let it sleep. No one touches it for twenty days."
The waiting was the hardest part. The Governor visited every few days, poking at the grey slab with his cane. "It looks like a flat rock, Prince Lu. Are you sure it won't just shatter when a horse steps on it?"
"If it shatters, Governor, you can have my head," Li Chen said. He wasn't being dramatic; he knew that in this world, failure meant death. But he wasn't afraid. He had checked his math a thousand times. He knew the strength of the iron and the density of the stone.
On the twenty-first day, the entire village gathered at the gorge. Even the farmers from the Pale Shoulders had come to see the miracle or the disaster. Li Chen stood at the head of the bridge. He looked at Lao.
"Remove the supports," he commanded.
Lao and his men went beneath the bridge. With heavy hammers, they began to knock away the wooden wedges that held the ribcage in place. One by one, the timbers fell away, splashing into the river below. The crowd held its breath. Every eye was fixed on the grey span.
The last support fell. The bridge didn't move. It didn't groan. It didn't sag even a fraction of an inch. It hung there, a solid piece of man made stone, defying gravity.
A low murmur went through the crowd. It wasn't a cheer yet; it was awe. They had never seen anything like it. A bridge without pillars. A road made of liquid that had turned into a mountain.
Li Chen didn't wait. He walked to his pony and climbed into the saddle. He signaled to a group of men who were waiting with a heavy cart. The cart was loaded with three tons of limestone from the hills—far more weight than any wooden bridge in the province could carry.
"Drive it across," Li Chen said.
The driver hesitated, his face pale. "Your Highness... the weight..."
"I will ride beside you," Li Chen said.
He steered his pony onto the bridge. The sound of the hooves on the concrete was different than on wood or dirt. It was a solid, ringing sound. The cart followed, its heavy wooden wheels creaking under the massive load.
They reached the center of the span. The water roared fifty feet below. Li Chen stopped his horse. He looked back at the crowd on the bank. He could see the Governor's eyes bulging. He could see Builder Zhou crossing himself.
Li Chen stood up in his stirrups. He jumped up and down on the bridge deck. The three ton cart sat perfectly still. The bridge didn't even vibrate. It was as solid as the cliff itself.
"It holds!" Lao screamed from the bank. "The Iron Prince has conquered the air!"
A roar went up from the people. It was a sound of pure joy. For a year, they had been cut off. Their goods had rotted in the fields because they couldn't reach the markets. Now, the road was open. And it wasn't just open; it was better than it had ever been.
Li Chen rode to the other side and dismounted. He felt a deep, quiet satisfaction. This wasn't just a bridge. It was a signal. He had shown the people that the old ways were not the only ways. He had shown them that he wasn't a weak exile to be pitied.
The Governor scrambled across the bridge, his fine shoes clattering on the concrete. He reached Li Chen and grabbed his hand, his face glowing with a new kind of respect. "Prince Lu! This is incredible! The Emperor must hear of this. A bridge that needs no pillars! You have saved the trade of the entire province!"
"I didn't save it for the Emperor, Governor," Li Chen said, pulling his hand away gently. "I saved it for the people who live here. And this is only the first one. I want a road like this stretching from the Pale Shoulders all the way to the city gates."
"But the cost, Your Highness! The iron alone..."
"The cost of a bridge that falls every three years is much higher than the cost of a bridge that stands for five hundred," Li Chen said. He looked at the men who were now dancing on his bridge, testing its strength with their own feet. "We have the stone. We have the iron. And now, we have the people who know how to use them."
As the sun set over the Broken Gorge, Li Chen sat on a rock and watched the traffic begin to flow. Carts, horses, and people streamed across the grey span. He felt the weight of his exhaustion again, but it was a good weight. He had built something that would outlast him.
He looked at his hands. They were still scarred, and his body was still weak. But he realized he didn't need the strength of a warrior to change the world. He just needed the strength of the earth and the logic of the mind.
"One bridge down," he whispered to the wind. "Now, let's talk about the city."
He knew the news would reach the capital soon. He knew the Imperial Architects would come to see his work, and they would bring their jealousy and their politics with them. But let them come. He had the liquid stone now. And once you know how to build a world out of stone and iron, you don't fear men who only know how to build with words.
Li Chen stood up and began the walk back to his palace. He had a lot of work to do. He needed to design a drainage system for the city. He needed to find a way to make the cement even stronger. And most of all, he needed to find a way to bring light into the dark, damp homes of his people.
The age of rot was over. The age of the blueprint had begun.