In the Ming Dynasty, I became invincible simply by extracting memories!

Shen Lian frowned.

Although he wasn't a military expert in later generations, he still understood the basic principles of the breech-loading cannon: the precise coordination of the main and auxiliary cannons was essential for a high rate of fire. If the casting process was substandard, with too large gaps, gunpowder gases would leak, reducing the range to as little as a few seconds, or even causing a barrel explosion and injury. Gunpowder, in particular, was the soul of a firearm; if it wasn't pure enough, the projectiles wouldn't even be able to penetrate a wooden board.

Shen Lian remembered Fang Xuejian, who was a graduate student majoring in chemical engineering before he transmigrated. Fang Xuejian had talked to him when they were in prison, saying that ancient processes such as steelmaking, gunpowder, and glassmaking, from the perspective of modern chemistry, were actually just a bunch of chemical reaction equations. As long as the principles were mastered, many seemingly mysterious "secret formulas" could actually be standardized and proceduralized.

"Take gunpowder for example," Fang Xuejian said enthusiastically, gesturing to him. "One part saltpeter, two parts sulfur, three parts charcoal—that's the old saying passed down from our ancestors. But how do you purify saltpeter? How do you refine sulfur? What kind of wood do you use to burn the charcoal, and to what degree? These are the real keys to determining the power of gunpowder. The black powder formula of the Ming Dynasty was actually close to the theoretical optimal ratio; the problem lay in the purification of raw materials and the control of the process, resulting in a huge difference in power."

Shen Lian only half understood what he heard, but he remembered one sentence: the same pound of gunpowder could double its power.

After Shen Lian finished inspecting the jammed breech-loading cannon, he also rummaged through the inferior gunpowder in the powder pack and had already made up his mind.

"General Tang," Shen Lian pointed to the pile of crudely made cannons and gunpowder, "these cannons do indeed have serious problems. The main cannons have many sand holes in their vents, the cannon burrs on the bullets haven't been polished, and the gunpowder is damp and contaminated. The most critical issue is that the Ordnance Bureau doesn't have standardized dimensions for casting cannons. Cannons from the same batch can vary in caliber by as much as a copper coin, and it's common for bullets not to fit into the main cannons. If this problem isn't solved, even if we replace them with a new batch of cannons, they'll still jam and leak."

Tang Kekuan had initially thought Shen Lian was just complaining, but he hadn't expected him to point out each of Shen Lian's faults so clearly, which made him think more highly of him. He sighed, "Mr. Shen is right. It's just that I'm completely ignorant about forging firearms."

Shen Lian cut straight to the point: "General Tang, I have a request. Although these cannons are of poor quality, they may be able to be improved. I would like to borrow the Ordnance Depot to test and improve these cannons. If it works, I dare not say that they can be compared with the top-quality ones from the Nine Garrisons, but at least it will save our brothers from dying on the battlefield."

Tang Kekuan sized up this Jinyiwei official, a hint of surprise in his eyes. He'd come to the front lines to burn down the Japanese pirate camp, and now he wanted to modify cannons? Was this man a Jinyiwei or a Ministry of Works official? The words that came out were: "There are a few old craftsmen in the arsenal, their skills are decent. If you want to try, I'll talk to Commander Yu." He added, "But as you can see from our arsenal, we have no money, no materials, just those three blacksmith furnaces. Don't think they're too shabby."

Shen Lian laughed and said, "That's enough. Even the best equipment is useless if you don't know how to use it. Besides, I'm not working for nothing." He took out a sheet from his pocket and handed it over. "These are a few rough suggestions for improvement that I just drafted. General Tang, please take a look. If they work out, I'd like to write to a friend in the capital who knows about firearms and ask for a more detailed plan."

Tang Kekuan took the list and glanced at it—the mother gun's bore had been smoothed with a reamer, an iron ring had been added to the bottom of the magazine for easy retrieval, the touch hole had been modified with an angled notch and a baffle, and the gunpowder had been granulated and sieved with rice wine… He was skilled in swordsmanship and archery, and not as proficient in firearms as Commander Yu, but he could still distinguish the general quality. The list was densely packed with about ten items, meticulously prepared, and clearly not something an amateur could fabricate. He looked up at Shen Lian, his gaze changing from curiosity to a hint of astonishment.

"Alright, I'll have the Ordnance Factory free up some manpower right away. Just tell me what materials you need." Tang Kekuan put the list away. "By the way, which government department does your friend work for? The Ministry of Works Ordnance Bureau?"

"Imperial Observatory".

Tang Kekuan was taken aback, thinking he had misheard: "People from the Imperial Observatory can build cannons?"

Shen Lian smiled and said, "He knows a little bit about everything."

That evening, Shen Lian spread out letter paper under the oil lamp, just about to pick up his pen to write a letter to Fang Xuejian. It had been at least two or three months since he left the capital. He wondered how that guy was doing at the Imperial Observatory, and whether he had made any progress with his strange experiments.

As soon as Xin looked up, Shen Lian stopped writing and thought for a moment.

The sight of gunpowder clumping due to dampness on the city walls, causing cannonballs to fly like stones, was still vivid in Shen Lian's mind. The scene of the breech-loading cannons jamming and leaking gas on the drill ground, with soldiers scrambling to react, was also still fresh in his mind. Fang Xuejian, a chemical engineering master's graduate from his previous life, had unique insights into gunpowder formulation and the purification of sodium sulfate. At the time, Shen Lian didn't take it too seriously, thinking the guy was a bit simple-minded and harmless. But now it was different. Now, on the southeastern front, he had witnessed firsthand the various shortcomings of the Ming army's firearms, and how many more people had died because of the lack of sufficient firearms.

He dipped his brush in ink and began to write:

"Old Fang, it's like seeing you in person after reading this letter."

I'm currently in Zhao'an, Fujian, in Yu Dayou's military camp. I only realized how much worse the situation was here than what we heard in the capital. Wu Ping, colluding with Japanese pirates, has amassed dozens of ships and several thousand men, all eyeing the lucrative Chaozhou region. There are also the intricate web of forces led by Zhang Lian and Xu Chaoguang. Yu Dayou has fewer than three thousand capable fighters under his command. Even more absurd is their firearms. The breech-loading cannons are so poorly made they look like they've been chewed by a dog; a copper coin could fit between the magazine and the main magazine. When ignited, gunpowder gases spew out from the gaps, burning our own men before killing the enemy. The gunpowder is even worse: the saltpeter isn't purified, the sulfur is mixed with clay, and the charcoal powder is uneven in size. It produces billowing smoke, and the projectiles only travel fifty paces before hitting the Japanese pirates' rattan shields and becoming motionless. The Japanese pirates below the city are laughing hysterically, while the brothers on the walls are green with rage.

I still remember all the boasts you made to me in prison. You said gunpowder wasn't anything mysterious—one part saltpeter, two parts sulfur, three parts charcoal—anyone could recite the formula. The key was in the purification of the raw materials and the control of the process. The saltpeter had to be purified to over 90%, the sulfur had to be refined, and the charcoal had to be made from willow or poplar wood, with specific techniques for the burning temperature. I only half understood back then, but I thought you were definitely knowledgeable. Now, standing on the city wall, watching my brothers die needlessly because of insufficient gunpowder and exploding cannons, I realize that every word you said was a matter of life and death.

Enough with the small talk, I need you to do two things for me.

First, write down your methods for purifying saltpeter, refining sulfur, and screening charcoal powder in detail and send them to me. The more detailed the better, so detailed that even a rough blacksmith could follow your instructions. Also, please include your improved gunpowder formulation. You know I don't understand chemistry, but I know you're reliable.

Secondly, could you help me prepare a casting specification? What is the molten iron ratio? What are the requirements for the mold? What is the tolerance range for the gap between the male and female casting cannons? How should the reamer be finished to smooth the inner wall? Please write it out clearly from beginning to end. It would be best if you could draw a diagram, but it doesn't matter if it's ugly, as long as it's understandable.

These two matters concern the overall situation of resisting the Japanese pirates. Okay, that's a bit of an overstatement. To put it bluntly, it concerns whether the few thousand brothers around me can die. You know, in my past life, I, Shen Lian, was the kind of person who would help those in need, and I haven't changed that even in the Ming Dynasty. Although this trait may shorten my life, now that I'm here, I can't just stand by and watch my men fall one by one.

By the way, how's your job at the Imperial Observatory? Did you manage to get the glass experiment done? Have those bastards from the Yan faction given you any trouble? If you really manage to get that mirror that can magnify several times, we'll be able to see the Japanese pirates' flags from miles away at sea. I'll put in a good word for you then, and you'll be able to walk around the Imperial Observatory with your head held high.

Alright, enough with the nonsense. Anyway, you owe me a drink, and I'll settle the score with you when I get back to the capital. Interest will be charged like usury.

Take care.

Shen Lian.

After finishing writing, Shen Lian read it through again from beginning to end. He was still a little unaccustomed to writing so much in one go. The souls of two modern people were trapped in the body of the Ming Dynasty. They knew each other inside and out and didn't need any of those flowery formalities.

He knew Fang Xuejian well. If you asked him for something earnestly, he'd put on airs and try to be literary; but if you treated him like a brother and laid out your difficulties directly, he'd do everything in his power. And that line in the letter, "I'll settle the score with you for that drink you owe me when I get back to the capital, with interest at usurious rates," Fang Xuejian immediately understood—this was genuine desperation.

Shen Lian sealed the letter with sealing wax and handed it to the express horse at the post station. From here to the capital, it would take about half a month by express horse. The round trip would take a month. In this month, he needed to get things moving first; practice and theory don't conflict, you learn by doing.

Yi Dong watched as he sealed the letter and handed it to the courier. "Young master, is your friend Fang Xuejian perhaps an extraordinary person? The things you wrote in your letter, such as purification, refining, and standardization, don't sound like things that someone from the Imperial Observatory would know."

Shen Lian thought to himself that this girl was quite perceptive. "He is quite remarkable. He is probably the only person in the entire Ming Dynasty who can both observe the stars and make gunpowder." Shen Lian felt that this description was not accurate enough, so he added, "Or rather, he is the only person in the entire Ming Dynasty who can treat observing the stars and making gunpowder as the same thing."

Yi Dong seemed to understand, but she didn't press the matter. Having spent these days by Shen Lian's side, she had grown accustomed to his occasional incomprehensible remarks, and to the unspoken familiarity he displayed when mentioning Fang Xuejian. That familiarity was like that of two fellow countrymen reunited in a foreign land, instantly understanding each other's meaning. She didn't understand this feeling, but she knew that this man named Fang Xuejian was very important to Shen Lian.

The following morning, three veteran craftsmen from the arsenal were brought before Shen Lian. The leader, surnamed Lu, had white hair and beard; his family had been blacksmiths for three generations, and their skills were among the best in Fujian. His two apprentices, surnamed Wang and Li, had calluses on their hands as thick as tree bark.

Old Lu sized up Shen Lian—a green official robe, an embroidered spring knife, a fair complexion, and no beard; he was from the capital. The old blacksmith's gaze held a craftsman's arrogance, but also an instinctive aversion to "a layman instructing a professional": "I heard the master is going to teach us how to cast cannons?"

Shen Lian wasn't annoyed. "I wouldn't presume to preach, but I have some ideas that I'd like to ask Master Lu for help with."

He picked up a bullet and pointed to the burrs on the edge, saying, "This wasn't polished; it gets stuck when loading." He then pointed to the inner wall of the main gun, explaining, "The inside isn't smooth; uneven friction makes it easy to jam. Smooth the inner wall with a reamer, and polish the edges of the bullet; loading will be twice as fast."

Old Lu took the cannon, scraped it, and then squinted and felt around the breech of the mother cannon. After a moment, he looked up, his arrogance lessened: "What you say makes sense, sir. I've thought about this before, but nobody listens. Those captains and lieutenants only know how to rush for cannons, they don't care whether you're comfortable using them or not. This job isn't difficult, I can make a reamer myself, I can make a batch in two days."

Shen Lian opened another gunpowder packet, poured the gunpowder inside onto the table, and spread it out. Old Man Lu and his two apprentices came over to look, and all three of them frowned simultaneously.

Shen Lian opened another gunpowder packet and poured the gunpowder onto the table, spreading it out evenly. The three craftsmen gathered around, their brows furrowing simultaneously—the particles varied greatly in size, the powder piled up, mixed with soil, sawdust, sulfur chunks, and even a few grains of sand and grass stems.

"The gunpowder particles are uneven and contain impurities. The burning speed is uneven, and the thrust depends entirely on luck," Shen Lian said. "By sifting the particles with a sieve, then re-granulating them with rice wine and drying them, the power can be increased by 30%."

Old Lu's eyes lit up. He rubbed a pinch of gunpowder between his fingertips, brought it to his nose, and smelled it. The pungent sulfur smell was mixed with a musty, earthy odor, clearly indicating that it had been dried after being damp. He then put a few more pieces of gunpowder in his mouth, chewed them, and spat them out.

"Sir!" His voice became serious. "I heard about this method from an old gunner. He worked at the Nanjing Ordnance Bureau when he was young, and he said that high-quality gunpowder has uniform granules, a glossy black color, doesn't stick to your hand, and has a pungent, acrid smell. Using alcohol to granulate it makes the granules compact, allowing the shells to fly thirty to fifty paces further! Unfortunately, the old gunner died long ago, and the technique has been lost. I didn't expect you to know about it, sir!"

Shen Lian smiled. He had no idea about the technique of using wine to granulate gunpowder; it was just something Fang Xuejian had mentioned briefly when he was bragging. Fang Xuejian had said that the power of gunpowder depended on three factors: the purity of the raw materials, the precision of the proportions, and the uniformity of the granules. Saltpeter needed to be purified to over 90%, sulfur needed to be refined to remove impurities, and charcoal needed to be made from willow or poplar wood, burned to the perfect temperature. The degree of saltpeter purification was limited by the technology of the time, but using rice wine or rice water as a binder during gunpowder granulation could improve the strength of the granules without affecting the burning speed.

"When that guy was talking, I thought he was being long-winded," Shen Lian thought to himself. "Now it seems that Fang Xuejian is actually quite capable; he's not just someone who brought a modern soul to the Ming Dynasty to get killed."

"Also," Shen Lian pointed to the bottom of the musket, "Master Lu, look, the touch port is straight, so sparks will fly into the gunner's face when it's lit. If you change it to an angle, or add a baffle, it will be much safer."

Old Lu nodded repeatedly: "That's simple, just add a baffle. I've seen the cannons of the Guangdong navy, and their flanks are all angled. I don't know why our Fujian cannons are made straight."

Shen Lian said, "Then change it to a slant."

Old Lu grinned, revealing a set of teeth stained yellow from smoking: "Alright!"

For the next two weeks, Shen Lian spent every day at the ordnance workshop. One day, while discussing mechanical matters with Old Man Lu, he noticed the ivory token that Old Man Lu wore close to his body and couldn't help but ask about its origin. Shen Lian simply said that it was an ordinary old personal item, and Old Man Lu didn't press the matter. The two of them stopped talking and focused on studying firearms.

The arsenal was located in the northwest corner of Xuanzhong City, covering a vast area with high walls surrounding the compound. At the base of the walls, piles of iron ore and charcoal formed small mountains. The three blacksmith's furnaces burned from dawn till dusk, the bellows whirring and the hammers clanging, the sounds audible from two streets away. Looking at the bustling scene before him, Shen Lian vaguely felt as if he were in a modern-day workshop, the three furnaces acting as three production lines, but unfortunately, all the power came from the arms of Old Man Lu and his two apprentices.

A thought flashed through his mind: Wasn't Fang Xuejian involved in glassmaking? What if he could create a lens to focus sunlight and melt iron…? The idea vanished in an instant. In this era, building a solar-powered furnace was roughly equivalent to teaching Yu Jiajun calculus.

Old Lu, his two apprentices, and Shen Lian squatted in the backyard, experimenting repeatedly. Old Lu precisely controlled the gap between the bullet and the main gun to within the width of a hair; having forged iron his entire life, he could achieve millimeter-precision with a single cut. After smoothing it, he used fine sandpaper dipped in tung oil to polish it until it was as smooth as a mirror.

Shen Lian watched Old Man Lu work, inwardly marveling. Modern CNC machine tools rely on laser measurement, with an accuracy of 0.01 millimeters; Old Man Lu relied on the feel of iron he'd had for sixty years. In terms of the number of sensors per unit area, his old fingers probably outnumbered any precision instrument. Of course, if Fang Xuejian heard this, that guy would definitely refute it from both a chemical and physical perspective.

The gunpowder granulation process used authentic glutinous rice wine purchased from Chaozhou Prefecture, which had a rich aroma. Old Man Lu spread the sifted gunpowder powder in a wooden basin, sprinkling wine while stirring until it became a moist paste. He then pressed it through a fine copper sieve to form uniform granules, which were then spread on bamboo trays to air dry. The dried granules were black, shiny, and firm, hard to the touch, and had a pungent, spicy smell, a stark contrast to the previous pile of grayish powder.

The breechblock was modified to be angled and fitted with a copper baffle. Old Lu also added a small iron ring to the bottom of the breechblock. The gunner could use an iron hook to pull and release the breechblock, which was several times faster than using his hands.

Everything is ready, just waiting for the test launch.