Black Corporation: Joseon

Sejong praised the elite nature of the General’s troops before getting to the main point.

“Are the cannons they carry on their shoulders the new ones?”

Upon Sejong’s inquiry, Hyang replied promptly.

“Yes, Your Majesty. It’s named ‘Fortified-style Siege Cannons¹.”

In response to Hyang’s reply, Sejong stroked his beard while expressing his appreciation. “‘Siege Cannons’… It’s a fitting name. However….,” his gaze was fixed on the shimmering barrel of the Siege Cannons. Sejong, who was looking at the silver glittering barrel of the said weapon, turned his head to Hyang.

“It’s not made of copper, is it?”

“Indeed, Your Majesty. It’s made of iron.”

“Iron?”

Listening to the conversation between Sejong and Hyang, Hwang Hee cut in. “Your Majesty, while copper is expensive, iron is also costly….”

Sejong raised his hand to interrupt Hwang Hee’s words. “Enough,” he remarked and continued, “The Crown Prince must have had a reason to use iron. We can talk about that later.”

“I understand.”

Sejong, who stopped Hwang Hee’s words, issued an order to Choi Hae-san. “I want to see its power.”

“Yes, Your Majesty.”

Upon receiving the order, Choi Hae-san gestured to the craftsmen standing nearby. As the craftsmen saw Choi Hae-san’s hand signal, they brought a board the size of a human body. The red cloth-covered board had armor plates lined up in a row.

Choi Hae-san pointed to the board with his baton and began explaining, “This is the armor plate that we’ll use as a target. Compared to the actual armor, the thickness of the iron plate is increased by 1 li (a traditional Chinese measurement unit, approx. 0.3 cm) to 4 li (approx. 1.3mm) for reinforcement.”

“Is that so?”

“Set up the target.”

“Yes, general.”

The craftsmen took the target to the opposite side of the demonstration area. Upon seeing the craftsmen installing the target far from where the cannon troops were located, Sejong called out to General Choi Hae-san.

“General, how far is that distance?”

“It’s about 250 bo (traditional Korean unit of length, approx. 300m), Your Majesty.”

“Ho!”

Sejong began to glow with admiration. Meanwhile, the craftsmen who finished installing the target signaled and ran to the ditch made under the earth wall.

Upon seeing the craftsman’s signal, the commander yelled at the cannon troops.

“Load the cannons!”

At the commander’s order, the cannon troops set up the Siege Cannons they were carrying on the ground.

“Clean the barrel!”

“Add gunpowder!”

“Add the cartridge paper²!”

“Load the lead ball!”

“Push in the lead ball!”

Following the commander’s order, all the cannon troops finished their process and returned to their loading stance, and the commander issued an order.

“Front cannon! Fire the cord!”

The cannon troops picked up the Siege Cannons, pulled the trigger halfway, and inserted the fire cord filled with gunpowder into the knob.

“Pull the trigger! Aim!”

The cannon troops pulled the trigger all the way back, stepped forward with their left foot, tilted their bodies slightly, placed the stock on their shoulders, and aimed at the distant target.

“Fire!”

Boom!

Smoke and sparks spewed out and disappeared into the air.

“Reload!”

The cannon troops who had finished shooting returned to their loading stance, and the craftsmen who had hidden in the ditch retrieved the target and returned.

“Amazing!”

“Such a powerful weapon!”

Sejong and the ministers couldn’t hide their surprise as they looked at the retrieved target plate.

There were 9 holes in the target plate.

Hyang and Choi Hae-san were full of pride as they watched Sejong and the ministers inspect the target plate with amazed faces.

“Truly amazing. I knew that cannons were powerful but their range was significantly shorter compared to arrows. However, this Siege Cannons has a range similar to arrows, and its power is incomparable. It is indeed the ultimate weapon.”

“The craftsmen have worked hard.”

Hyang modestly responded to Sejong’s praise. Choi Hae-san, who was listening to Hyang’s reply next to him, nodded vigorously. There was a small tear in his eye.

At Choi Hae-san’s strong reaction, Sejong turned to Hyang. Seeing Hyang’s somewhat embarrassed smile, Sejong sighed.

“General Choi, just how hard did the craftsmen have to work… Please explain the process of completing this cannon.”

“Yes, Your Majesty. So….”

※※※※

The process of making a barrel began with the crafting of a specific tool to create the iron body of the barrel.

“To shape the barrel using a hammer, we need a specially made anvil,” the blacksmith explained.

Following this instruction, the craftsmen used high-carbon steel (also known as ‘bong steel’ in Korean) to create a custom anvil. Unlike a conventional anvil that has a flat top, the custom anvil had a long groove shaped like a series of semi-cylindrical pillars, starting from a large semi-cylinder to a smaller one just slightly bigger than the targeted thickness of the barrel.

After the anvil was completed, the next item ordered was an iron core made of bong steel, slightly thicker than the inner diameter of the barrel.

After the custom tools were made, the crafting process was guided step by step.

Following the instructions, the blacksmith and other craftsmen began to roll a sheet of iron of appropriate size.

Once the iron sheet was adequately rolled, they inserted the iron core into the center and started hammering it on the custom anvil. When the ends of the iron sheet met as it was rolled, they sprinkled a mixture of iron and charcoal powder on the seam before placing it into a furnace. The intense heat of the furnace melted the mixture, filling the creases of the rolled sheet.

Once the crevices were completely filled, the craftsmen checked for smoothness and accuracy. If everything was fine, they hammered the circular barrel to give it an angular shape.

This was to facilitate the subsequent processing by stabilizing the barrel.

Finally, after heating in the furnace, they buried the barrel in ashes to cool it, and then used a tool invented by the blacksmith to smooth the inside.

After the interior was smoothed and both the exterior and interior of the barrel were confirmed to be straight without warping, they made the barrel’s section octagonal. Then they made a female screw in the back and inserted a male screw with a cap attached to it. The cap was the part where the touch hole, the hole through which the gunpowder is ignited, was installed.

However, the work did not end there. The wooden body made by the woodworker, including the trigger and the lock, and the barrel were assembled. Then, a trigger guard made by a brass craftsmen was attached, as well as a front sight and a rearsight. On the end of the muzzle, a robust and pointed part was installed. The real struggle started from then. There were no rifling grooves in the barrel of the gun drawn by the blacksmith. This was intentional.

“Going forward, the number of things to make and test will gradually increase, so I can’t do everything myself, can I?”

When five prototypes were completed, Hyang, together with Choi Hae-san and Lee Chun, began a comprehensive performance test.

“First, let’s find out how much gunpowder it can withstand.”

“Yes, Your Highness.”

“The existing barrel could hold one ‘nyang’ (a unit of weight in the Joseon period), but let’s start from half of half ‘nyang’, shall we?”

“That seems appropriate.”

Choi Hae-san, Lee Chun, and the craftsmen began the test by filling the barrel with half ‘nyang’ of gunpowder and a bullet.

For safety, they fixed the barrel in a rig, attached a string to the trigger, and hid behind a protective wall.

“Fire! Fire! Fire!”

Bang!

The loud noise filled the testing area, and the test ended when the barrel withstood up to one and a half ‘nyang’ of gunpowder.

“Considering the intended use of this barrel, there’s no need to go up to two ‘nyang’.”

“Agreed.”

“Then let’s try with blasting powder (mercury fulminate).”

In the subsequent test, the barrel withstood one and a half ‘nyang’ of blasting powder. After confirming the results, the blacksmith changed the test item.

“Then let’s find out what the optimal amount of gunpowder is. They said that they killed a Jurchen wearing armor with a musket at a distance of 40 ‘bo’ (approximately 50m), so let’s use that as a standard.”

“Yes, sir.”

This time, they gradually reduced the amount of gunpowder. The result of the test was two ‘don’ (approximately 7.5g) of blasting powder. The bullet fired from the barrel cleanly penetrated a four ‘li’ (approximately 1.2cm) thick iron plate set up as a target.

After checking the result, the blacksmith looked at Choi Hae-san and Lee Chun.

“Looking at the power, it seems possible to kill from an even greater distance, doesn’t it? The further the better, right?”

“That’s obvious.”

“Then shall we see if it’s possible at 50 ‘bo’?”

“Yes, Your Highness,” Choi Hae-san responded with excitement.

In the conducted test, the long gun barrel that contained two “don” (approx. 7.5g) of gunpowder had pierced a target up to 70 “bo” (approx. 85m). Beyond this range, although the bullet reached, it failed to hit the target despite shooting more than 20 times.

’70 bo, that’s unexpected, isn’t it? Perhaps it’s time to start with rifling³?’

Despite the results exceeding his expectations, Hyang had no intention of stopping.

From that point onwards, Choi Hae-san, Lee Cheon, and the craftsmen were no longer enjoying their work.

“General, it seems that the process of loading the gun takes too much time due to sieving and ramming. Let’s try it without these steps.”

“But without those steps, the bullet might fall out…”

“Can’t we custom make the bullets to fit the barrel?”

Hyang’s suggestion gave Choi Hae-san something to consider, and he nodded his head, “It seems worth trying.”

Hyang planned to impose trial and error based on the content of a video he saw on the Internet. However, in the subsequent experiment, the long gun barrel caused a problem after firing five shots.

“The residue from the gunpowder makes it strenuous to prepare for another shot.”

“I see.”

“So, we need to sieve after all…” 

However, Hyang shook his head. “General, think about it. Do you think cavalrymen, who ride faster than humans, have the leisure to sieve while charging at full speed?”

“That’s true, but…”

Choi Hae-san, Lee Cheon, and the craftsmen began to search for a solution. However, it was not easy for people to come up with ideas about rifling.

‘Do I have to step in again?’

On a rainy day, when Hyang was considering his involvement, one of the artisans who had been staring blankly out of the window suddenly stood up.

“Ah!”

“What’s the matter!”

“How about drilling a groove?”

“Drilling a groove?”

Hyang pointed to the ground with his finger as he explained. “Do you see that ditch? The stagnant water flows down the ditch, doesn’t it? The flame of the gunpowder might flow in a similar way, right? If we drill a long groove inside the barrel, won’t the flame flow and the residue also escape through the groove?”

At the artisan’s words, Choi Hae-san and Lee Chun looked at Hyang. Hyang nodded.

“It seems worth a try.”

With Hyang’s decision, seven more barrels were manufactured.

“Let’s make two barrels each with 3, 6, 9, 12, and 15 grooves, and compare them with barrels without grooves.”

“Yes.”

They accepted the order, but the artisans faced a new dilemma.

‘How do we even drill the grooves?’ After several sleepless nights of contemplation, they finally crafted a dedicated tool, and drilled grooves in the barrels, ranging from 3 to 15.

In the subsequent tests, Choi Hae-san, Lee Chun, and the artisans encountered a new problem. The power of the output seemed to diminish as the number of grooves increased.

“That’s expected. The more grooves there are, the more power will be lost through them,” Lee Chun pointed out the cause, and later Choi Hae-san murmured with a troubled expression, “Is a three-barrel gun[Triple Rifle all barrels can be fired independently, in any sequence and at any time, without them affecting each other.]][ the only answer after all?”

“What are the exact results?”

In response to Hyang’s question, Lee Chun flipped through the book with the results as he replied, “There is little loss of power up to 6 grooves, but there’s a lot of residue. From 9 grooves, the residue decreases but the power drops significantly.”

At Lee Chun’s response, everyone scratched their heads.

“Do we need to go with 9 grooves…”

“The problem is that the power visibly drops from there…”

“Is 6 grooves the only answer then? But that also has the residue problem…”

While they were agonizing over the problems that couldn’t be solved at the same time, Jang Yeong-sil, who had been unable to bear watching, opened his mouth. “How about twisting the grooves?”

“Twisting the grooves?”

At Jang Yoeng-sil’s words, everyone’s attention focused on him.

Watching from behind, Hyang clenched his fists under the desk. ‘Ahjussi (mister), nice!’

Hyang quickly composed himself and ordered Jang Yeong-sil. “Astronomer Jang, please explain in detail.”

“Yes, your Highness. So… um… wouldn’t the length increase if we twist the grooves like a screw? If that happens, even with 6 grooves, there will be enough length for the residue to escape. And because the grooves are twisted, the force from the gunpowder explosion won’t be able to escape straight away, right?”

The meeting room fell silent at Jang Yeong-sil’s explanation. As Choi Hae-san and Lee Chun pondered over what Jang Yeong-sil meant, they both exclaimed at the same time.

“That’s it!”

“That’s it! Crown Prince, twisting (it) may be the answer!”

At the words of Choi Hae-san and Lee Chun, Hyang made a decision. “Then let’s try it.”

That night in his room, Hyang grumbled with a tired expression as he got into bed.

“Ah… The path to the rifled musket is so long and difficult… Explaining the concept of surface area in terms of length… And the ability to understand it as if it’s obvious… Are all the people living in this era monsters?”

The decision to twist the grooves drilled into the inside of the barrel had been made, but a problem arose from that.

“How many rotations should we make?”

Facing this problem, people were again in a quandary. Hyang had to step in again.

“Make a prototype with half a rotation up to two rotations at half a rotation intervals!”

“Orders received!”

And so, the artisans had to spend another night to create a new barrel.

1. There’s no particular reference for the names, so I decided to translate it to names that kinda make the most sense.[↩]
2. Before the formation of lead bullets, ammunitions are stuffed in a cartridge paper like this: https://en.wikipedia.org/wiki/File:Chassepot_paper_cartridge.jpg[↩]
3. the arrangement of spiral grooves on the inside of a rifle barrel.[↩]

Ngl, the technical terms in this chapter will be the death of me. Not me, literally researching about grooves, barrels, and cartridge paper at 2 a.m in the morning. Really makes me wonder, how on earth did the author manage to research all these things while writing this novel?

Here's an emoji to describe me, when tl'ing this chapter: 🥵🤕