Song Dynasty: Yuan Dynasty, you didn't expect this, did you? I'm still alive.

In September of the 45th year of the Jingyan era (1320), the autumn winds of North India, carrying dry sand and dust, swept across the battlefields on the outskirts of Delhi.

Ghazi Malik's army defeated the remnants of Khuslao Khan's forces, and the once invincible usurper Sultan Khuslao Khan was captured alive.

Soon after, a heart-wrenching scream rang out in Delhi's square as Huslaohan was publicly executed, his blood staining the cobblestones beneath his feet.

Ghazi Malik, dressed in magnificent Sultanate robes, ascended the throne amidst a retinue of his ministers, taking the title "Giyasuddin Tughluq," thus beginning the rule of the new Tughluq dynasty over the Delhi Sultanate.

Before the joy of the coronation ceremony had faded, news from South India poured cold water on Tughluq's anger.

He learned that the two kingdoms of Hosala and Kakatiya in South India had dared to take advantage of the turmoil in the Sultanate to launch a surprise attack on the Deccan Plateau in alliance with the Eastern Song Dynasty. What was even more despicable was that they had actually succeeded in capturing this strategic location.

"A bunch of arrogant clowns!" Tughluq slammed his hand on the armrest of his throne, the inlaid jewels trembling with rage. His eyes were as fierce as a wolf's, and he immediately ordered, "Bring up that captured soldier who participated in the Deccan campaign!"

Soon, a ragged, wounded soldier was brought in, his knees slamming heavily on the cold ground, trembling with fear.

"How did Kafur Khan lose?" Tughluq leaned forward, his voice as cold as ice, and asked viciously.

The soldier seemed to be dragged back to the brutal battlefield by those words. His body trembled even more violently, his teeth chattered, and his voice was choked with sobs: "The enemy... the enemy can summon heavenly lightning! They blasted the city gates open in an instant... Lord Kafur Khan could only lead his cavalry in a charge in the open field, and they were defeated by the enemy's heavenly lightning..."

"Heavenly lightning?" Tughluq's face instantly darkened, his brows furrowing as he cursed inwardly: What kind of nonsense is this? If the enemy could really summon heavenly lightning, they would have already stormed into Delhi to seize his Sultanate.

Unconvinced, he sought out several soldiers who had fled back from the Deccan Tramp, and after much questioning, he finally pieced together the whole story.

It turns out that the enemy possessed a weapon capable of launching iron balls from a distance, with immense power far exceeding that of ordinary weapons.

Tughluq had never seen such a weapon before, and immediately ordered his men to search everywhere to find out the details of this weapon.

Several days later, an Arab merchant who frequently traveled between the East and the West heard about the Sultan's bounty and took the initiative to request an audience.

"Great Sultan, the weapon you speak of must be made of gunpowder." The merchant bowed respectfully. "However, I am quite puzzled as to why the gunpowder of these Easterners is so powerful."

The Arabs were already aware of the existence of gunpowder when they traded with the Song Dynasty.

After gunpowder was introduced to the Arab world, people quickly discovered its value in warfare and developed corresponding firearms. However, the craftsmanship was still relatively crude, and they could only improve the bamboo fire musket of the Song Dynasty into a wooden tubular shooting firearm.

Tughluq automatically ignored the merchant's description of the "difference in power" in the second half of his sentence, and a gleam of wild joy flashed in his eyes. He waved his hand forward: "Do you have the method for making gunpowder? As long as you offer it up, I can give you any amount of gold and silver!"

A greedy glint immediately appeared in the merchant's eyes, his Adam's apple bobbed involuntarily, and he bowed deeply, replying, "I am willing to serve the great Sultan!"

He changed the subject, looking slightly troubled, and said, "However, I only know that gunpowder exists, but I don't know the specific manufacturing method. Please give me some time, Sultan. I will return home immediately and purchase the gunpowder manufacturing method!"

Eager to acquire the weapon, Tughluq nodded without hesitation and immediately ordered a chest of gold and silver to be brought to the merchant as a deposit: "Go quickly and return! I await your good news!"

In his view, the Delhi Sultanate had already suffered two defeats in the south, and if it did not figure out the details of the enemy's weapons, it would likely suffer a third or fourth defeat in the future, which he absolutely could not tolerate.

Three months later, the Arab merchant indeed returned to Delhi with several craftsmen.

Tughluq immediately summoned his ministers and had the artisans demonstrate this firearm—the Madafa—in public at the palace's drill ground.

This is a wooden tubular firearm. After the craftsman lights the fuse, there is a muffled "bang" and an iron bullet is fired. Its effective range is only about fifty meters.

While it can inflict fatal damage on unarmored targets at close range, its penetrating power is limited, making it difficult to penetrate heavy armor, let alone breach sturdy city walls.

Although the power of this motor was far different from the power of the weapons described by the soldiers in the Middle East and Song Dynasty, Tughluq was certain that the principles behind them were the same.

Undeterred, he pressed on, "How would you make this weapon blast open a city gate from two hundred meters away?"

The Arab craftsman shook his head repeatedly, his tone resolute: "That's impossible, Great Sultan. To achieve that kind of power, the motor would need to be magnified dozens of times, and it would have to be made of metal. But that would make the weapon incredibly heavy, impossible to move. Moreover, with current technology, it's impossible to manufacture such a massive metal firearm."

Tughluq, however, did not believe this superstition. He firmly believed that if the Song people could make something, his craftsmen could certainly do it too.

Now that we know how gunpowder is made, we can have our domestic craftsmen repeatedly imitate and improve it, and one day we will be able to create weapons that are even more powerful than those of the Song people.

He then asked, "What are the drawbacks of this weapon?"

"Reporting to the Sultan, if it rains, the gunpowder will get damp and the weapon will lose its power," the craftsman replied truthfully.

Upon hearing this, Tugluk was overjoyed, and the gloom on his face vanished.

Does gunpowder become ineffective when it gets damp in the rain?

Wouldn't it be incredibly easy to defeat the Eastern Song Dynasty then?

He immediately rewarded the Arab merchants and artisans as agreed, and then began to secretly prepare for the southern expedition.

In 1321, the 46th year of the Jingyan era, Tughluq's rule had just been consolidated when he hastily launched his first southern expedition.

He personally led 30,000 of his own soldiers and 20,000 servants recruited from various tribes, marching in a grand procession toward Dvajiri on the Deccan Plateau, determined to reclaim this lost territory.

The city of Dvajiri sits atop an isolated, conical rock mountain about 200 meters high, its steep, almost vertical slope resembling a sword thrust into the earth.

The mountain is surrounded by thick city walls and a wide moat. The city walls are several meters high and covered with firing holes, making it easy to defend and difficult to attack.

For the Delhi Sultanate, which lacked artillery, such a city was an impregnable fortress.

Previously, when Khuslao Khan attacked this place, it also took a lot of time, through a long siege, political negotiations and internal divisions, before he finally captured the city.

After arriving at the city, Tughluq did not rush to send his elite troops to attack the city. Instead, he ordered his servants to serve as the vanguard and attack the city walls at the foot of the mountain.

The soldiers, carrying sandbags for filling the river, approached the moat, cursing and swearing.

Just as they were about to reach the riverbank, a burst of gunfire suddenly erupted from the city wall, the "bang bang bang" sounds like rolling thunder.

The soldiers fell like felled wheat, dozens died instantly, and the rest were terrified, throwing down their sandbags and running away.

"Useless!" Tugluk cursed angrily upon seeing this, then shouted, "Archers, provide cover! Suppress the fire from the city walls!"

Hundreds of archers immediately stepped forward, nocked their arrows, drew their bows, and fired upwards at the city tower.

In an instant, a rain of arrows rose into the sky like a dark cloud, falling densely towards the city walls. The musketeers on the walls were forced to slow their firing and scramble for cover from the arrows.

On the city wall, Yang Zhi was observing the situation below through his telescope. Seeing the Sultan's archers begin to suppress the enemy, a cold smile appeared on his lips. He ordered the messenger beside him, "Prepare the ten tiger-crouching cannons on the city wall to fire! Give these archers a good lesson!"

"Boom! Boom! Boom!"

Ten tiger-crouching cannons roared simultaneously, their muzzles spewing out dazzling flashes of fire.

A thousand small lead bullets were fired like a storm, sweeping towards the archer formation below the city.

The archers had no time to react before they fell in droves. Soldiers hit by multiple lead bullets were instantly riddled with blood and gore. Even their leather armor was as flimsy as paper and offered no protection.

Tughluk witnessed the power of the cannon firsthand, and his face turned deathly pale.

The loss of dozens of archers pained him deeply—these archers needed years to develop muscle strength and archery skills to become combat-ready, and now so many had died at once, making it impossible to replenish their numbers in a short period of time.

He gritted his teeth and reluctantly ordered, "Withdraw! Retreat temporarily! Continue the siege of Dvajiri!"

After the Sudanese army withdrew to a safe distance, they began to set up camp, forming a siege around the city of Dwagiri.

Ten days later, a light drizzle began to fall from the sky, the fine rain quickly wetting the ground.

Tughluq stood at the entrance of his tent, gazing at the rain-soaked city, a triumphant smile spreading across his face: "Heaven is on my side! Today is the end for the Song army!" He immediately ordered: "All troops, attack! Besiege the city again!"

Just as Tughluq had predicted, the Song army's firearms did not fire again on the rainy day—the gunpowder was damp and could not be ignited at all.

However, the rain also affected the fighting capacity of both sides. The Sudanese army's servants struggled to advance on the muddy ground and were repeatedly thwarted during the siege.

Tughluq was reluctant to send his elite troops into battle; while Yang Zhi's servants, taking advantage of the city walls, fought tenaciously and repelled the Sudanese army's attacks time and time again.

After a whole day of suffering heavy losses, the Sudanese army hadn't even reached the edge of the city wall, their efforts were in vain.

Helpless, Tughluq had no choice but to order another withdrawal and return to his camp to rest.

Frustrated by the repeated setbacks, he decided to send people to build catapults to bombard the city walls with this traditional heavy weapon.

On the city wall, Yang Zhi, through his telescope, clearly saw the Sudanese army building catapults. He couldn't help but laugh and teased his adjutant beside him, "Seriously, what era are we living in? Still using such old-fashioned catapults?"

Several days later, the Sudanese army pushed dozens of catapults to a point a kilometer away from the city wall.

Before they could adjust their angle and get within firing range, the two Divine Might General Cannons on the city wall roared to life.

The artillerymen had already calculated the trajectory, and two heavy iron balls, accompanied by a whistling sound, accurately struck the two foremost catapults.

"Crack! Boom!" The wooden catapult was instantly smashed to pieces, sending wood chips flying. One of the iron projectiles, after shattering the catapult, still carried by its momentum, bounced and struck a soldier nearby.

With a muffled "thud," the soldier's chest was instantly crushed, blood and internal organs gushing out, and he died on the spot.

The surrounding soldiers were so frightened that they froze, held their breath, and dared not utter a word. Their faces were filled with fear, and they could not even move their feet.

Tughlük witnessed this scene from behind and was so frightened that his heart tightened and cold sweat instantly broke out on his back.

The Song army's cannonballs not only have a long range, but are also so accurate. If one of the cannonballs happens to hit his command tent, wouldn't everything be over?

He dared not linger any longer and immediately ordered: "The entire army must retreat! Retreat to a place five miles outside the city!"

Thus, the two sides reached a stalemate.

Tughluq led tens of thousands of troops on an expedition, consuming huge amounts of food and supplies. Meanwhile, the surrounding areas had already been ordered by Yang Zhi to be scorched earth, making it impossible for the Sudanese army to obtain supplies from the local area.

After months of stalemate, the army's food supplies were running low, and the soldiers were full of complaints and morale was low. Tughluq had no choice but to order a retreat, and the first southern expedition came to an abrupt end.

Yang Zhi stood on the city wall, watching the retreating Sudanese army, but did not order a pursuit. He worried that Tughluq was feigning a retreat to set up an ambush, and for the sake of caution, it was safest to hold the city.

. . .

In the same year, a great uproar was stirred up in the academic circles of the Eastern Song Dynasty.

Guo Yun, a scholar at the Gewu Academy, after years of dedicated research, was the first to propose the theory of calculus.

The birth of this theory shocked the entire academic world of the Eastern Song Dynasty like a thunderbolt, and Guo Yun became famous as a result, becoming a landmark figure of the Gewu Academy.

However, the good times did not last long.

Not long after, Lai Bu, a master from Tsinghua Academy, suddenly spoke out, claiming that he was the first to invent calculus and that Guo Yun was nothing more than a thief who stole other people's achievements.

For a time, scholars from both academies took sides, and the two sides argued endlessly, engaging in heated debates and refusing to give in.

Ultimately, neither of them could convince the other, so they decided to determine ownership of calculus through a duel.

This story quickly spread throughout the streets and alleys of the Eastern Song Dynasty, becoming a well-known topic of conversation among Song families.

People discussed this "academic duel" over tea and after meals, jokingly calling it "the first great battle between Gewu Academy and Tsinghua Academy," adding a lot of fun to their dull lives.