My palace is full of female protagonists.

On the way back to Feng Kingdom, the caravan stopped to rest beside a quiet village. Night had fallen, and the stars twinkled, adding a touch of tranquility and mystery to the long journey. On this seemingly ordinary night, Duan Zhenghuai, the powerful ruler of Feng Kingdom, summoned Lin Yi.

Lin Yi was roughly forced to kneel on the ground by the guards. His waist was forcibly pressed down, preventing him from straightening up. He could only face his monarch in a humble posture. Duan Zhenghuai sat upright at the head of the table, dressed in a magnificent dragon robe. His brows revealed an imposing aura that commanded respect without anger. He slowly scrutinized the young man before him, as if trying to see through Lin Yi's appearance to the secrets hidden deep within his heart.

"Your name is Lin Yi?" Duan Zhenghuai's voice was deep and powerful, each word seemingly coming from the abyss, carrying an undeniable authority.

Although Lin Yi's heart was churning with turmoil, he tried his best to remain calm on the surface and respectfully replied, "Yes, I am the thirteenth generation descendant of the Lin family of Chaling in Feng State."

Duan Zhenghuai nodded slightly, a hint of amusement flashing in his eyes: "Chaling has always been a royal fiefdom. So, you're really just a pawn carefully arranged by that old man?" The "old man" he was referring to was, without a doubt, a powerful figure behind Lin Yi.

Lin Yi's heart skipped a beat. He knew that this was both a test and a warning. He cautiously replied, "I am but an insignificant member of the family, and dare not presume to call myself a pawn."

Duan Zhenghuai smiled slightly, seemingly dissatisfied with Lin Yi's answer. He continued to press, "Did you marry and have children in that other country? Did you leave any ties behind?"

Lin Yi's heart sank. He knew the seriousness of this question; a careless answer could bring utter destruction to himself and his family. He took a deep breath and replied, "To protect my identity, I have not married or had children. I only have an old man in my family who has already been sold, and the house is a temporary rental."

Upon hearing this, Duan Zhenghuai nodded, seemingly quite satisfied with Lin Yi's frankness: "So, you're all alone now?"

Lin Yi was filled with mixed feelings. He had to emphasize again: "Although I am alone abroad, I still have the Lin family of Fengguo in my heart. My elderly parents are at home, and I think about them all the time."

Duan Zhenghuai smiled, a smile that was both meaningful and somewhat sarcastic: "You're still young, and your parents must be young too. When you return to Feng Kingdom, you might find that you have a few more younger brothers and sisters. That wouldn't be surprising, hehe."

Upon hearing this, Lin Yi could only lower his head and agree, but his mind was racing as he quickly calculated how to deal with any possible changes.

Duan Zhenghuai took a small sip of the fragrant tea in his hand. The aroma rose gently, intertwining with the deep light in his eyes, making him appear particularly solemn. He spoke slowly, his voice low and powerful: "The Empress intends to summon you. What are your plans? We have not yet left the territory of Yunnan Kingdom. I can provide you with a fast horse, which will be sufficient to escort you back safely."

Upon hearing this, Lin Yi felt a mix of emotions. He was well aware of the complex situation that might be hidden behind this summons, yet he also knew that he could not easily refuse. He took a deep breath, respectfully kowtowed to the ground, and said with a hint of determination and resolve in his voice, "If Your Majesty truly intends for me to return, I will certainly do my utmost to live up to Your Majesty's grace and your high expectations!"

Upon hearing this, Duan Zhenghuai's lips curled into a barely perceptible bitter smile, a strange displeasure rising within him. He knew that while Lin Yi's words were sincere, they also revealed a hint of helplessness and struggle in his reluctance to leave. He gently shook his head, his tone both playful and earnest: "Do you think you can easily leave the capital of Yunnan Kingdom if I were willing to let you go? Besides, I've heard you're quite skilled and adept at martial arts. Why not stay by my side as a guard? That would be better than kneeling here so groveling."

Upon hearing this, Lin Yi's heart pounded rapidly. He realized that he might have inadvertently touched a nerve with Duan Zhenghuai. He quickly composed himself, kowtowed again, and said in a voice filled with fear and self-reproach: "Your Majesty, I have misspoke. I hope you will forgive me. In fact, I learned a secret technique in the palace when I was an official, and I am willing to offer it to Your Majesty."

Seeing this, Duan Zhenghuai's eyes flashed with satisfaction. He slowly stepped forward and personally helped Lin Yi up, his tone more intimate and trusting: "In my eyes, all the guards who can stand by my side are brothers I regard as my own. Whatever skills you have, whatever thoughts you have, there is no need to be so reserved. Stand up and speak."

Lin Yi stood up, his expression focused and expectant. He asked a servant for paper and pen, then bent down to sketch, his brushstrokes revealing his familiarity with and enthusiasm for what he was about to display. Soon, a drawing roughly outlining the shape of a honeycomb briquette and the tools used to make it appeared on the paper. He looked up, a hint of pride in his eyes, and explained to Duan Zhenghuai, "Back then, in the main hall, I was fortunate enough to see that drawing about honeycomb briquettes. The drawing not only depicted its appearance in detail but also included the basic manufacturing method. Unfortunately, I never got to see the finished product myself before I was dispatched to the Yunnan Kingdom for some reason."

Duan Zhenghuai stared at the blueprints, his brows furrowed slightly, looking somewhat puzzled: "This just looks like coal, doesn't it? What's so special about it?"

Upon hearing this, Lin Yi smiled slightly and began to elaborate on the many advantages of honeycomb briquettes: "Your Majesty may not know, but these honeycomb briquettes, though seemingly ordinary, actually contain great wisdom. First, their design allows the coal to burn more completely, improving thermal efficiency and reducing waste. Second, honeycomb briquettes are easy to stack and transport, greatly saving space, which is especially important for our army. Furthermore, honeycomb briquettes are not charcoal, but rather fragments of coal, which we originally wouldn't have used and would have simply piled up in the mines. Moreover, they produce less smoke when burning, resulting in a relatively smaller impact on the environment, which is also very beneficial."

At this point, Lin Yi's eyes gleamed with even greater determination: "It is especially worth mentioning that in the cold winter, heating and cooking are major problems for the army on the march. The design of honeycomb briquettes allows us to carry enough fuel at once without frequent resupply, thus ensuring the mobility and combat effectiveness of the army. This is undoubtedly a major strategic resource for our Yunnan Kingdom."

As Duan Zhenghuai listened to Lin Yi's explanation, the doubt in his eyes gradually dissipated, replaced by deep admiration and anticipation. He realized that this seemingly ordinary guard might truly bring unexpected changes and opportunities to Yunnan Kingdom. Therefore, he gently patted Lin Yi's shoulder, his tone filled with encouragement and trust: "You didn't go to another country as a spy for nothing, did you? Perhaps you'll become a great asset to our Feng Kingdom. I will consider how to apply this to our army and people's livelihood. After returning home, continue your research, and report to me immediately if there is any progress."

Lin Yi's expression was solemn, and his tone was serious: "Zhao Yingqing specifically instructed that the production of honeycomb briquettes should be carried out in two steps. The first step is to mass-produce the special tools used to make honeycomb briquettes; the second step is to actually make the honeycomb briquettes themselves. Both of these technologies are vital national assets and must be firmly controlled by the royal family. They must not be easily leaked to the public, and even less should neighboring countries be allowed to learn them, so as not to pose a potential threat to our country."

Upon hearing this, Duan Zhenghuai stroked his chin, lost in thought. He knew all too well that in this turbulent era, even the slightest technological advantage could be crucial in determining a nation's fate. He spoke slowly, his tone tinged with wisdom and helplessness: "Indeed, it's impossible to keep it a secret forever, but if we can keep it hidden for five or six years, it will be more than enough to gain the upper hand when dealing with neighboring countries. Think back to those days; if that stubborn old man hadn't even suppressed his own son, how could our Feng Kingdom have ended up in such a disorganized state? Now, with a weapon like these honeycomb briquettes, we can only focus on improving people's livelihoods first. Improving our military is out of the question."

Duan Zhenghuai instructed his guards to arrange a new identity for Lin Yi. Even after returning to Feng Kingdom, Lin Yi never left Duan Zhenghuai's side by more than a hundred paces.

Meanwhile, amidst his busy political duties, Zhao Chengyu unexpectedly received several urgent military letters from Gao Lingyan. Unfolding the letters, he was greeted by lines of strong, vigorous handwriting, detailing the situation at the front and informing him that the operation to recapture Lanling Kingdom was progressing exceptionally smoothly, with frequent reports of victories and virtually no major obstacles. After reading them, Zhao Chengyu felt a surge of pride and ambition, filled with confidence and anticipation for the future strategic plan.

To gain a more intuitive understanding of the war situation and to provide a more direct demonstration for discussions with key court officials, Zhao Chengyu immediately ordered a spacious and bright area to be cleared out on the left side of the imperial study, where a large sand table was specially commissioned. This sand table was made of the finest rosewood, with intricate cloud and thunder patterns carved on the frame, giving it a dignified and elegant appearance. The tabletop was a smooth, mirror-like marble slab, beneath which was inlaid a meticulously crafted sand table base, preparing for the upcoming simulated war exercise.

The news spread like wildfire, quickly reaching the ears of Prime Minister Gao and Prime Minister Su. Both prime ministers were veterans of the court, seasoned by history, and possessed keen insight and profound understanding of politics. They were very curious about Zhao Chengyu's novel initiative, so on a sunny afternoon, they met at the Imperial Study, eager to see for themselves what this legendary sand table looked like.

The moment Prime Minister Gao and Prime Minister Su entered the Imperial Study, their steps involuntarily slowed. Their gazes were instantly drawn to the enormous sand table in the center of the room. That sand table, like a magnet, firmly held their attention, causing them to forget everything around them. The sand on the table, with its base of fine sand, seemed to hold endless stories and secrets, each grain waiting to be discovered.

Prime Minister Gao and Prime Minister Su exchanged a glance, their eyes filled with both confusion and anticipation. They were puzzled as to why Zhao Chengyu would suddenly set up such a sand table in the Imperial Study—was it merely for amusement? But then they thought again; Zhao Chengyu was known for his diligent governance and would never act so rashly. Therefore, their eyes were filled with anticipation, hoping they could glean something from the sand table or glean some deeper meaning from Zhao Chengyu's actions.

Zhao Chengyu stood before a dark black robe embroidered with gold thread and dark dragon patterns. The golden dragon designs shimmered in the sunlight, showcasing his supreme imperial power and majesty. He sat upright before the sand table, his expression focused and solemn, as if engaged in a crucial task. In his hand he held an exquisite wooden pusher, every inch of which was polished smooth as jade, offering an excellent feel. He gently slid the pusher across the sand table, each movement so careful, as if afraid of damaging even a single part of it.

As Zhao Chengyu moved his hand, the sand grains that had been lying dormant on the sand table seemed to come alive. They began to slowly gather together, forming various shapes. These shapes varied in height and length, and gradually, a vivid outline of the country appeared on the sand table. The outline was smooth and proportionally harmonious, like a work of art sculpted by nature itself, leaving people in awe.

On the sand table, mountains, rivers, cities, roads, and other elements are all present, arranged in a well-organized manner to form a complete and detailed picture of the country. Zhao Chengyu's technique is skillful and precise. As he pushes the sand, he examines every inch of the land on the sand table with his eyes, as if he is thinking about how to better utilize these resources and how to more effectively protect this land.

Prime Minister Gao and Prime Minister Su watched this scene with deep admiration and awe. They knew that Zhao Chengyu was not merely playing with sand, but was using this method to plan the future of the nation, demonstrating his wisdom in governance and strategic vision. They understood that this sand table was not a toy, but an important political tool, a powerful assistant that could help Zhao Chengyu better control the national situation and formulate strategic decisions.

Upon seeing the Yunnan Kingdom and the recently conquered Lanling Kingdom clearly displayed on the sand table, the two prime ministers exchanged astonished glances, their faces showing disbelief. This sand table not only accurately recreated the current national territory, but even the smallest details of the terrain were lifelike, as if the vast land had been shrunk to the size of this table, leaving one to admire the ingenuity of its creator.

Seeing this, Zhao Chengyu smiled with satisfaction. He gently picked up a small water bottle from the side and carefully sprinkled a few drops of water on the sand table. The water droplets quickly seeped into the sand, making the terrain on the sand table more stable and less likely to be blown away by the wind. Then, he took out several small red flags engraved with place names from the table and placed them one by one at key locations on the sand table, such as the capital city and important border towns. In this way, the key points of the entire battle situation became clear at a glance, providing great convenience for subsequent decision-making.

As the two prime ministers witnessed this scene, their respect for Zhao Chengyu's wisdom and foresight deepened. They knew that this was not merely a simple sand table, but a manifestation of the Emperor's meticulous planning and profound foresight for the future of the nation.