Chief Armaments Master of the Ming Dynasty

In the winter of the second year of the Chongzhen reign, in Shaanxi, at Ziwu Ridge.

Winter came earlier and was colder than usual that year.

Snowflakes, like goose feathers, blanketed the sky, turning the vast mountains into a uniform silver-white.

Between heaven and earth, only the mournful sound of the wind passing through the pine forest and the rustling sound of snow falling on the bare branches remained.

Lin Fan stood silently beside the newly built blast furnace deep in the valley, gazing at the flames spewing from the furnace opening.

This was the second month after he forged his first piece of steel.

In two months, he built three more identical blast furnaces.

Each one has undergone repeated improvements—the furnace body is taller, the inner wall is smoother, and the blower system is more efficient.

The fire in the furnace never went out, day or night.

In this desolate mountain wilderness, sealed off by heavy snow, this simple "steel plant" is like a tireless behemoth, devouring ore and charcoal and spitting out molten steel.

Han Jinhu became Lin Fan's most capable assistant.

The blacksmith in this Yanchang County is now able to independently manage a blast furnace—he knows every step by heart, from charging and temperature control to tapping steel.

He even trained several apprentices, all of whom were clever young men selected from the camp. They learned diligently and worked hard.

"Brother Lin, this batch is of exceptionally high quality!"

Han Jinhu used tongs to hold a piece of steel billet that had just cooled down and brought it close to the firelight to examine it carefully.

The silver-gray fracture surface shimmered with a fine, silky sheen.

He tested the hardness with a file, a satisfied smile spreading across his face. "This piece can be used to make knives, and it can also be used to make cannons."

Lin Fan took the steel billet, examined it from all angles, and nodded.

But he didn't laugh. Han Jinhu noticed and put down what he was doing.

"Brother Lin, is something on your mind?"

Lin Fan did not answer immediately.

He stared at the furnace fire, remained silent for a moment, and then whispered, "Brother Han, how much steel can we produce a day now?"

"Four furnaces. Each furnace yields about twenty catties. After accounting for losses, we can get about seventy catties of good steel a day."

"Seventy catties..." Lin Fan murmured, repeating the number. "A small cannon requires three hundred catties of steel. A good knife weighs five catties. Seventy catties, what can you make in a day? Not even half a cannon."

Han Jinhu scratched his head: "Then let's build a few more furnaces. There's plenty of space in this valley; we can fit ten more."

"Where are the people?" Lin Fan looked at him. "We need people to build the furnace, people to mine, people to make charcoal, and people to transport materials. Even including the more than a thousand newly surrendered refugees, we only have two thousand five hundred people in total now. We can already spare more than two hundred for steelmaking. If we spare any more, who will keep watch? Who will gather supplies?"

Han Jinhu was stumped by the question.

He knew Lin Fan was right.

They are not government officials and have no stable source of food, pay, or taxes.

You have to rely on yourself for everything.

Two thousand five hundred people needed to eat, wear clothes, stand guard, fight, and also smelt steel and make cannons.

There are never enough people.

Lin Fan squatted down, picked up a twig, and scratched it on the snow.

Han Jinhu leaned closer to look and saw some lines and symbols that he couldn't understand.

"I'm thinking about whether we can improve the furnace," Lin Fan said as he worked. "The current furnace can only produce twenty catties of steel per batch. If we can enlarge the furnace chamber, we can produce fifty catties, a hundred catties... and the output will increase."

"Enlarge the furnace?" Han Jinhu frowned. "Will the heat be even? What if the outside is steel but the inside is still a lump of pig iron?"

"So we need to find a way to make the temperature inside the furnace more uniform." Lin Fan tapped a circle on the ground with a twig. "I plan to add a preheating chamber at the bottom of the furnace, so that the blown-in air is preheated before entering the furnace chamber. This will make the furnace temperature higher and more uniform. Also," he drew a few more lines on the ground, "the arrangement of the crucibles also needs to be changed. They can't be piled together; there need to be gaps so that the flames can evenly coat each crucible."

Han Jinhu only half understood what Lin Fan was saying, but he believed him.

From Huanglong Mountain to Lubao Ridge, from Shanxi to Shaanxi, Lin Fan's methods never disappointed him.

"Brother Lin, just tell me what to do, and I'll do it."

Lin Fan stood up and patted the snow off his hands.

Gazing at the blast furnace spewing flames, the firelight illuminated his face, roughened by the mountain winds.

"When spring comes, I want to have ten furnaces erected in this valley first," he said, his voice not loud, but with an undeniable certainty. "By then, we can produce at least two hundred catties of steel a day. In a month, besides weapons and armor, we can also make ten cannons. In a year, one hundred and twenty cannons."

One hundred and twenty steel cannons.

Han Jinhu was so shocked by this number that he swallowed hard.

He couldn't imagine what it would be like to see more than a hundred steel cannons firing simultaneously.

But Lin Fan could imagine it. He had seen it. In later images, in museum paintings, in those wars that changed the course of history.

"One hundred and twenty cannons, not enough," he said in a low voice, as if talking to himself, "but at least, they can help us gain a foothold in this cannibalistic world."

He turned and walked deeper into the valley.

There, he was setting up a gunpowder workshop.

---

The gunpowder workshop was built in a hidden cave deep in the valley.

This location was personally chosen by Lin Fan.

The cave extends deep into the mountainside; its dry and cool interior makes it an ideal place to store gunpowder.

What's even more amazing is that although the entrance is narrow, the inside is a completely different world, with a spacious area that can accommodate dozens of people working at the same time.

Even if an explosion were to occur, the mountain would be able to absorb most of the impact, preventing it from affecting the campsite in the valley.

A dozen oil lamps were lit inside the cave, their dim light illuminating the focused faces of the craftsmen.

They were carrying out the most dangerous and crucial step in gunpowder production—the purification of saltpeter.

The quality of the saltpeter soil that Lin Fan collected from various places varied.

Some of them were scraped from the base of walls in abandoned toilets, pigsties, and stables;

Some of them were dug up from piles of wild animal droppings in deep mountains and forests;

Some were salvaged from the battlefield—in abandoned camps of government troops, one could often find old urine pits containing nitrates.

These nitrate soils contain an astonishing number of impurities.

Soil, sand, grass stalks, and even... in short, without rigorous purification, they are simply unusable.

The purification method was taught to me step by step by Lin Fan.

First, the saltpeter needs to be soaked in hot water and stirred constantly to fully dissolve it.

Then let it stand to settle, allowing heavy impurities such as mud and sand to settle to the bottom.

Next comes filtration—using multiple layers of coarse cloth, filtering again and again until the filtrate changes from a turbid, earthy yellow to a relatively clear, pale yellow.

The filtered saltpeter solution was poured into a large iron pot and simmered over a low flame.

As the water evaporates, fine crystals will precipitate on the surface of the liquid.

These crystals are the initial purified saltpeter.

But this is not enough.

The initially crystallized saltpeter also contained a large amount of table salt and other salts.

To remove these impurities, recrystallization is necessary—the crude nitrate must be dissolved again, filtered again, and boiled again.

This process needs to be repeated three to five times until the crystals are as white as snow and refract pure light in the sunlight.

The person in charge of this process is an old craftsman named Lao Weitou.

He was originally a firecracker maker in Ningxiang County, a craft passed down from his ancestors.

After Li Zicheng captured the county town, Lin Fan rescued him from the ruins.

At first, he was trembling with fear, thinking that he would be forced to serve the "bandits".

After working there for a while, he found that although the conditions were tough, Master Lin treated people fairly and provided plenty of food.

More importantly, the methods Master Lin taught him for purifying saltpeter were far superior to his ancestral techniques.

"Master Lin, this batch of saltpeter is of exceptionally high quality." Old Wei held up a handful of snow-white saltpeter crystals and handed them to Lin Fan, his face full of smiles amidst the deep wrinkles on his face.

Lin Fan took it and examined it carefully under the oil lamp.

The crystals are pure white with uniform particles, and they make a slight crisp sound when crushed between your fingertips.

He then lightly touched a little with the tip of his tongue—it was cool and refreshing, with the distinctive bitterness and saltiness of saltpeter.

The saltiness is very mild, which means that the impurities in the salt have been removed well.

"Okay." He nodded. "This batch can be used in medicine."

"To be used in medicine" was a code word in the gunpowder workshop, meaning that this batch of saltpeter met the purity standards and could be used in the gunpowder preparation process.

Old Wei breathed a sigh of relief and carefully packed the batch of saltpeter into a dry earthenware jar, sealed it with oil paper, and affixed a label with the date and batch number—this was also a rule set by Lin Fan.

Every batch of gunpowder raw materials must be recorded.

Any problems can be traced back to the source.

Lin Fan surveyed the cave.

The sulfur purification area, the charcoal burning area, the raw material storage area... every area is well-organized.

Sulfur purification uses a distillation method—sulfur ore is placed in a sealed earthenware jar and heated. After the sulfur sublimates, it condenses at the mouth of the jar, yielding pure sulfur powder.

The charcoal is made from willow and poplar wood, which are porous and contain little ash.

The firing temperature must be strictly controlled during firing; it should not be overheated or underheated.

The burned charcoal should be ground and sieved while it is still hot to obtain fine and uniform charcoal powder.

After the three raw materials are purified and tested to meet the required standards, they enter the most crucial process—proportioning and mixing.

Lin Fan stood at the entrance of the mixing workshop, listening through the thick wooden door to the extremely faint sounds inside, like grinding tofu.

He knew that they were mixing gunpowder.

Using a specially made wooden mill, he evenly crushed and mixed the three raw materials—saltpeter, sulfur, and charcoal—in a moist state, according to the optimal ratio he had determined through repeated experiments.

Smoking and open flames are strictly prohibited throughout the entire process, as are collisions of metal objects.

Before entering, everyone must change into soft-soled cloth shoes and is not allowed to carry any metal objects.

This was a lesson he learned through countless experiments—including one that nearly blew him away.

He almost died that time.

A shard of an anvil flew past his scalp and embedded itself in the earthen wall behind him.

From then on, the rules of the gunpowder workshop became ironclad.