"Why!"

"Why is that!"

At the remark of "mass production is impossible," Sejong and the ministers shouted in anger.

Especially Sejong, with a face full of rage, confronted Hyang.

"Why do you say it is impossible?"

"It is impossible due to the current situation of Joseon."

"So, why is it impossible! This is not different from what you keep saying! It is not about impossibility, but about finding a possible way, isn't that your belief!"

"I am deeply sorry, but it is impossible due to the current situation of Joseon. The reason is..."

"You brat!" Sejong shouted loudly.

However, Hyang only wore a bitter expression. 'One of the most frustrating things is being told you can't do something.

But what can you do when the situation is a mess?' Seeing Sejong unable to calm his anger, Hwang Hee intervened in the conversation.

"Your Majesty, please calm your anger. There must be some circumstances."

"Hoo~. Hoo~."

At Hwang Hee's words, Sejong took a deep breath.

After barely calming his anger, Sejong glared at Hyang and spoke.

"Explain the reason."

"Yes, Father. I will speak accurately. The production of Deokgapsik gunpowder is possible. However, mass production is impossible."

"Why?" At Sejong's question, Hyang explained the reasons.

- To make Deokgapsik gunpowder, high-purity acetic acid and sulfuric acid are needed.

In the current situation of Joseon, it is difficult to obtain large quantities of stone and sulfur.

- There is also the issue of cotton cloth.

The main material for Deokgapsik gunpowder must be high-quality cotton cloth without fluff.

However, looking at the current situation of Joseon, the 5-seungpo, known as Jeongpo, is only used for tax payments, and the 3-seungpo or 4-seungpo is too poor to be used as currency.

"As I explained above, since high-purity acid is used, skilled artisans are needed. Of course, as can be seen from the Sanguiwon or the Military Equipment Bureau, there are skilled artisans. However, the number is too small for mass production."

"There is another problem with the main material of Deokgapsik gunpowder, which is pig oil."

"Why? Isn't pig oil also a material that needs to be imported?"

"No. It is a product that comes from our Joseon."

"Then why is it a problem?"

"Because the main materials of pig oil are pig bile and cow bile."

"Ah!" At Hyang's answer, Sejong and the ministers had to sigh simultaneously.

To make nitroglycerin, a large amount of glycerin was needed.

However, in the current situation without a petrochemical industry like in the 21st century, the only method Hyang could choose was to extract glycerin from the soap-making process.

However, the supply of raw materials was an issue.

The most straightforward thought was pig fat, but the body fat percentage of pigs was 15%.

To put it arithmetically, if a pig weighed 100 kg, that meant it had 15 kg of fat.

Even if all the fat and other fatty tissues were recovered during the butchering process, it was not possible to recover 100%, and the glycerin extracted through the saponification process was even less.

"In simple terms... even if everyone in Joseon eats pork three meals a day, it would be impossible to supply enough glycerin for military use."

Hyang, who was spinning his pen while examining the results, shook his head.

"Whether in the 21st century or now, eco-friendly natural products are economically disastrous... Long live petrochemical industry! Long live heavy chemical industry!"

"It is truly regrettable. I wish I had not known that such excellent gunpowder could be made. It would have been better if I had not known..."

At Sejong's lament, the ministers nodded in agreement.

"That is a resignation. Your Majesty, resignation in national defense leads to the path of ruin."

At Hyang's rebuttal, Sejong shouted angrily.

"Who does not know that! But what can I do when the situation of Joseon does not help!"

"What is the reason for Your Majesty's efforts? Is it not to overcome the difficult circumstances of Joseon?" At Hyang's plea, Sejong froze.

Seeing Sejong like that, Hyang raised his voice, veins popping in his neck.

"Even now, at this moment, starting with me, General Choi Hae-san and General Lee Cheon, along with the military officers and artisans, are racking their brains to find solutions! Your Majesty, I believe survival is a challenge! Survival is a challenge against death! Resignation is death! For me, the word resignation is unknown!"

"Your words are correct!" Sejong trembled with emotion.

"The moment I ascended to the throne, I vowed to do everything for the rise of Joseon! You have reminded me of what I had momentarily forgotten; you are indeed a loyal subject! Listen, everyone! Gather your scattered hearts once more! Risk your lives to succeed in this endeavor!"

The ministers, equally swept up in emotion, responded in unison.

"We will risk our lives to follow your command!"

Later, the overworked ministers all muttered, "That time, we should not have done the inspection of District 51. This brat's mouth is a curse..."

As mentioned before in front of Sejong, Hyang never gave up on the mass production of glycerin.

Even amidst the busyness, one day, while sleeping, Hyang suddenly sat up.

"Cooking oil! Well done, my head! You have done well again!" The next day, as soon as dawn broke, Hyang rushed to District 51 to find Choi Hae-san.

Meanwhile, Choi Hae-san, perhaps looking for Hyang, ran over with a bright face as soon as he saw him.

"Your Highness! I have been waiting!"

"General! I think I have found a way regarding pig oil."

"I also have an idea!" Upon realizing they were both looking for the same thing, a moment of awkwardness passed.

After tidying up his expression, Hyang spoke.

"General, please go first."

"Your Highness, you go first..."

"It's fine."

With Hyang's concession, Choi Hae-san spoke first.

"My thought is, how about using soybeans?"

"I had the same thought!" Hyang and Choi Hae-san immediately began to make soybean oil and entered into experiments.

After confirming the results of the experiments, Hyang and Choi Hae-san put their heads together.

"Doesn't it seem alright?"

"Yes, Your Highness."

"Let's report to Father!"

"Yes!" Upon receiving the report, Sejong looked greatly pleased and gazed at the ministers.

"The Crown Prince has achieved another merit!"

"Indeed!"

"Thus, we can further strengthen the national defense of Joseon!"

"Long live!"

In the process of securing soybeans, the soybeans from the farm connected to the livestock farm on Neobeol Island were used first.

The test results confirmed that the leftover soybean pulp after extracting the oil could be used as feed for cows and pigs.

However, since the soybeans harvested from the livestock farm alone could not meet the demand, Joseon earned the title of "the first country in world history to officially recycle resources."

The efforts of the Joseon court to obtain oil were a "war with the kitchen."

Pig fat and beef fat were widely used in cooking because they added a savory flavor when grilling or frying food.

Because of this, the court paid to collect pig bile and cow bile, leading to the birth of the term "Jijang-gun" following "Dongjang-gun."

The court's full-scale "war with the kitchen" began because of soybeans.

At that time, soybeans were one of the important food sources in Joseon.

Moreover, as a country that produced a lot of soybean paste and soy sauce, the demand for soybeans was enormous.

To solve this situation, Sejong thought of the best solution.

"If farmers who volunteered to migrate to the northern territories create soybean fields, the court will purchase all their harvest! This will solve the issue of the migrants' livelihood and the supply of raw materials!"

"We will follow your command!"

Due to this method, an outcome different from the original history occurred, with a significant increase in the number of farmers willing to migrate north.

Through various attempts, Joseon secured a path to greatly increase the production of Deokgapsik gunpowder.

However, Hyang's expression did not brighten much.

"Considering the amount being consumed now, the increase we are seeing is not enough. The amount used by the military has increased, but the civilian use is also considerable."

Looking at the reports piled up on one side of the desk, which were anxious about the lack of gunpowder, Hyang frowned and muttered while looking at the world map hanging on the wall.

"Is it really the south?"

"Is this all you have seen?" After a heated debate over gunpowder, Sejong looked at Hyang with a slightly regretful expression.

At Sejong's question, Hyang shook his head.

"No, the most important things are still left."

"The most important things?"

"First, I will show you the cannon, General."

"Yes, Your Highness. Bring in the cannon soldiers!"

"Yes, General!" After a moment, a group of cannon soldiers entered the demonstration area.

"One, two! One, two! Stand at attention! Left face!"

"Ready!" At the command of the leading officer, the cannon soldiers moved in unison, facing Sejong.

"Present arms!"

"Charge!" At the command of the commander, the cannon soldiers simultaneously performed a military salute.

Sejong, who returned the salute of the soldiers, did not hold back his praise for General Choi Hae-san and Hyang.

"Seeing the soldiers' discipline and order, they are not ordinary elites! It seems the efforts of the Crown Prince and the General are evident!"

"They are truly elite soldiers!"

"I have been in the court for quite a long time, but I have not easily seen such elite troops!" The ministers also did not hold back their praises for Sejong's commendation.

The cannon soldiers, who received the praise from Sejong and the ministers, were filled with pride.

Seeing that from the side, Hyang also felt a sense of pride. 'I rolled them so much for their drill training!' When a satisfactory number of rifles had been produced, Hyang requested support from soldiers and officers from Sejong.

When the officers and soldiers finally arrived, Hyang could not hide his disappointment.

"They clearly said these were selected from the Shigyesa, but... they seem elite, but..."

Comparing the soldiers he saw before him with the military life he experienced in the 21st century and the armies of the European powers in the 19th century, as well as the U.

S. military during the Civil War, the discipline and elite nature of the soldiers before him were considerably lacking.

Hyang, tilting his head in thought, clicked his tongue.

"Tsk! It can't be helped. I have to roll them."

Thus, the soldiers were first mobilized for the construction of their lodging and the construction of a large-scale testing ground for various weapons.

"I thought they came for military matters..."

The soldiers, who picked up shovels instead of weapons as soon as they arrived, were a bit bewildered, but they had no significant complaints.

This was because Hyang's food was exceptionally good.

At least every three days, pork and beef were served.

The soldiers held a meat feast with excitement.

In the meantime, a peculiar item caught the soldiers' eyes: a grill placed over a stove.

The thick cast-iron item had grooves on all sides, and as the meat was grilled, the oil that came out flowed along those grooves and collected in a bowl.

After the meal, those bowls were immediately sent to the artisans' workshop.

While the soldiers were mobilized for construction, Hyang gathered with General Choi Hae-san, General Lee Cheon, and the officers from the training center.

They discussed the naming of the various parts of the newly created cannon and created commands for drill training.

"Your Highness, do you think these drills and movements, and commands you have named for drill training are truly useful? They are already doing similar training."

Upon hearing Hyang's words, the officers from the training center doubted the necessity.

The battles they had experienced were clashes between groups.

The tactics to win such battles were to maintain formation until the end.

The Joseon army had also conducted related training quite diligently.

"So that was why the disgrace happened during the invasion of Tsushima?" At Hyang's pointed remark, the officers fell silent.

During the Tsushima invasion, Lee Jong-mu decided to attack the stronghold of the pirates who refused to surrender.

To carry out this attack, Lee Jong-mu drew lots to decide who among the commanders of the left and right armies would go.

As a result of the drawing, Park Sil's left army landed and began to advance, but they were ambushed by the enemy, causing the formation to collapse and resulting in over 180 deaths.

It was only natural that Hyang, after reading the report from that time, would explode in anger, saying, "There was no strategy or tactics!" Even setting strategy aside, the tactical aspect was also lacking; after landing the left army, there was no additional operation established to respond to difficulties such as enemy ambushes, and the left army was simply pushed forward.

Ultimately, since Hyang's criticism was valid, the officers proceeded to study drill training and bayonet techniques together with Hyang.