In this realistic war game, only I understand the course of the battle.

After Lingbi, no southern army field force north of the Yangtze River could withstand the Yan army. He Fu, with only a dozen or so personal guards, broke through the encirclement outside Lingbi and fled towards the Huai River. He was unchallenged—Zhu Di hadn't sent anyone after him. A general who had lost his main force and fled alone didn't need to be pursued; letting him return to Nanjing was itself a devastating blow to the morale of the southern army. Even before the news of the Lingbi victory was on its way, the garrisons along the north bank of the Yangtze surrendered without a fight. Tianchang surrendered, Liuhe surrendered, and Yangzhou had surrendered long before Lingbi. From the Huai River to the Yangtze, the Yan army's advance was like a red-hot knife cutting into solidified lard, encountering no resistance whatsoever.

Shen Du stood on the riverbank at Guazhou Ferry, facing the surging Yangtze River. In July, the river surface gleamed with a leaden gray light under the midday sun; the waves were small, but the undercurrents were turbulent, and the river wind made his armor flutter loudly. On the opposite bank was Zhenjiang, and the Southern Army flags on the city walls were clearly visible through his binoculars. One hundred and twenty li west of Zhenjiang was Nanjing. In that city lived the Jianwen Emperor, the Six Ministries and Nine Ministers, and the capital city walls that had not been touched by military might since the Hongwu reign. It had taken him more than three years to fight his way from Baigou River to Guazhou Ferry. Behind him, one hundred thousand Yan troops were gathering along the riverbank, banners like clouds, warhorses neighing, and their iron armor forming a dazzling band of light in the sunlight. Zhao Laoliu squatted on the riverbank, dismantling the iron hoops of the battering rams and re-oiling them. The battering ram he brought from Beiping had already had its wheels replaced twice, and the iron plates on the chassis were riddled with holes from arrows and lead bullets, but he couldn't bear to replace them—this battering ram had been pushed from Gaocheng to Lingbi, and from Lingbi to Guazhou Ferry, and every dent had been repaired by rivets hammered in by his own hands. "Master Li, Zhenjiang is right across the river." Zhao Laoliu put down his wrench, stood up, and looked at the opposite bank. "Take Zhenjiang, and Nanjing will be at our feet."

"There's no need to attack Zhenjiang." Shen Du put down his binoculars and pointed towards the Zhenjiang city gate on the opposite bank. "Look at the flags on the gate—yesterday there were three commander's flags, today there's only one left. The Zhenjiang garrison has begun to retreat. Sheng Yong has withdrawn all his main forces back to Nanjing, preparing to defend the capital to the death."

Nanjing. The Imperial City.

Emperor Jianwen, Zhu Yunwen, sat behind his desk in the Fengtian Hall, his face deathly pale. The incessant chirping of cicadas outside was irritating; several eunuchs used long bamboo poles to swat them down, the poles striking the leaves with dull thuds, but the sound was negligible compared to the clamor of the court officials. The military report of the fall of Lingbi had arrived yesterday: Ping An had been captured, Chen Hui had been captured, thirty-seven generals had been captured, over one hundred and fifty civil officials had been captured, twenty thousand warhorses had been seized, and He Fu's fate was unknown. This was the last field force of the court north of the Yangtze River to be annihilated, following those at Zhengding, Jiahe, Gaocheng, Dezhou, and Qimeishan. Qi Tai and Fang Xiaoru each proposed diametrically opposed plans—Qi Tai suggested holding the line and awaiting reinforcements, while Fang Xiaoru implored His Majesty to temporarily avoid direct confrontation.

"Your Majesty, the Yan army has reached Guazhou Ferry, and Zhenjiang is in imminent danger. There are still 170,000 troops defending the city. The Nanjing city wall was built by Emperor Taizu Gao, and it is high and thick. We also have ample food and supplies. As long as our army holds firm and does not venture out, the Yan army will be forced to retreat after a prolonged siege," said Qi Tai, Minister of War, stepping forward to report.

Fang Xiaoru stepped forward, cupped his hands, and said, “Your Majesty, I believe that what the Minister of War said is self-deception. Most of the 170,000 garrison troops are newly recruited soldiers from the capital garrison who have never fought in battle, and apart from Sheng Yong, there is no other general in the outer city who can command a large army. Once Zhenjiang falls, the Yan army will be at the city gates. What use will high walls and thick fortifications be? I implore Your Majesty to temporarily avoid the enemy’s advance, move the capital to Huguang, and wait for the armies from all over the country to gather before making any plans to recover.”

"Move the capital?" Jianwen's voice was very soft, as if he were talking to himself. "Where to? Huguang? Jiangxi? Or—"

He didn't finish his sentence. No one could answer the question for him. Zhu Yuanzhang passed the throne to him and built the Nanjing city walls to be the most fortified in the world, but he never told him what an emperor should do if one day the walls were still standing but the city was surrounded by enemies. He pushed aside the memorials on his desk, stood up, walked to the palace entrance, and looked at the stone steps outside the palace, whitened by the summer sun. The cicadas were still chirping.

On July 12, the Yan army crossed the river.

The crossing point was chosen thirty li upstream from Guazhou Ferry, where the river was relatively narrow, and the opposite bank was a reed marsh west of Zhenjiang, with few defenders. Sheng Yong had transferred all of Zhenjiang's main force to the ferry crossing on the front of the river defense, but he didn't have enough troops to deploy along the entire riverbank. Shen Du had sent men in advance to thoroughly scout the sentry posts on the opposite bank—behind the reed marsh was only a thousand-household garrison, less than eight hundred men, and fewer than a hundred muskets. The crossing began at dawn. Shen Du arranged the first wave of assault boats, all light, small, flat-bottomed boats, each carrying twenty infantrymen. Gu Zhang led swordsmen and shieldmen as the first boat to storm the beach, their mission being to seize the hard ground passage in the reed marsh and hold the shield line, covering the subsequent boats as they approached the shore. Huo Zhen followed with the second boat with mounted archers, all crossbows mounted on the bow for alternating fire. Zhao Laoliu's breaching team was mixed in with the third boat, carrying gunpowder canisters, to blow up the defenders' fortifications after reaching the shore. While the Yan army feigned an attack on the front of Guazhou Ferry on the north bank, Shen Du personally led a strike boat fleet to slant across the river from upstream.

When the defenders in the reeds spotted the fleet, the first boat had already crossed the river. A warning gong sounded in the morning mist, and the Southern musketeers hurriedly loaded their weapons, but the mist hadn't dissipated, obscuring visibility, and the first volley of fire landed in the water. Gu Zhang was the first to jump off the boat, his boots sinking into the mud. He planted his shield on the mudflats, pressing himself against it. Spearmen thrust their lances over his shoulders, piercing several Southern infantrymen trying to block the shore from the reeds. His old left arm injury had been warned again by the medic before the crossing, but he couldn't care less at this moment, only pushing the shield formation forward step by step. The second boat followed closely behind, and the musketeers dismounted—before the horses were even brought aboard from the stern—and began firing arrows from foot positions on the shore to suppress the musketeers in the reeds. On the third boat, Zhao Laoliu used gunpowder canisters to blast a corner of the wooden palisade surrounding the defenders' fortifications.

When Sheng Yong received news that the Yan army had crossed the river upstream, the feint attack on Zhenjiang had already been going on for an hour. He couldn't allocate his forces—although the Yan army's fleet attacking from the front was small, their battering rams and cannons were all positioned at the front, creating a formidable impression. The main force of the Yan army's central army was pouring onto the south bank from the upstream breach, and Zhu Neng was leading his cavalry to assemble on the south bank, directly outflanking Zhenjiang.

On July 15th, the Yan army besieged Nanjing. Looking north from Jin Chuan Gate, the Yan army's banners stretched for over ten miles. Zhu Di's central command tent was pitched at the foot of Zhongshan Mountain, and 100,000 troops were besieging Nanjing. On the city walls, Sheng Yong's defenders stood ready. The city gates were tightly closed, the drawbridges were high in the air, and the defenders had piled up sandbags and buckets of lime behind the crenellations. The Nanjing city walls were built during the Hongwu era using rammed earth slabs of bluestone and glutinous rice mortar. The foundation of the walls was several meters thick, and each gate opening was equipped with a heavy gate. This was the most formidable city wall Shen Du had ever seen—thicker, higher, and denser than any of the cities of Dezhou, Jinan, or Lingbi. He stood on the earthen slope outside Jinchuan Gate for a long time, repeatedly scanning the defensive deployment on the city wall with his binoculars. He found that the city wall was almost entirely fortifications designed to defend against frontal attacks—sandbags, crenellations, crossbow holes, and musket firing positions all pointed outwards. He did not see any deep reserve positions inside or outside the city wall to deal with street fighting or sudden internal changes.

He put away his binoculars and returned to the central command to report to Zhu Di: "Shengyong's city walls are very strong, but his defenses are only one layer. All the fortifications face outwards, and there is no in-depth defense line inside the city. Once the city gates are opened from the inside, the defenders on the city walls will be attacked from both sides." Zhu Di nodded without saying anything more.

July 17th. Li Jinglong stood inside the Jin Chuan Gate tower, peering through the gaps in the crenellations at the banners of the Yan army outside the city. Several trusted advisors stood behind him, none of them speaking. On the table before him lay a letter from Zhu Di urging him to surrender—to hand over the city. "Li Jinglong, you were once Jianwen's Grand General of the Northern Expedition. You commanded 600,000 troops at the Baigou River, and you lost the defense of Dezhou. Now you are in Nanjing, with 170,000 men inside and 100,000 Yan troops outside. The city walls are thick enough, but think it through—how many of these 170,000 men still listen to you? Does Jianwen still trust you? Does Prince Gu, Zhu Hui, trust you? Surrender the city, and your wealth and status will remain unchanged; do not surrender, and the day the city falls will be your death."

Li Jinglong folded the letter of surrender and stuffed it into his sleeve. He stood up and said to his advisor, "Go tell Prince Gu that it will be at the third watch tonight at Jin Chuan Gate."

That night, the heavy gate of Jinchuan Gate was slowly hoisted open, and the city gate opened from the inside. Li Jinglong and Prince Gu, Zhu Hui, stood inside the gate opening, followed by the guards who had opened the gate—none of their torches were lit, only the moonlight illuminated the open gate. When the Yan cavalry poured into Nanjing through Jinchuan Gate, Sheng Yong was still deploying defenses on the city wall. When he received the news that "Jinchuan Gate has opened," he froze for a moment, then slowly removed his helmet and looked towards the city. He saw the Yan cavalry rushing down the main street from Jinchuan Gate towards the imperial city, saw the guards on the city wall throwing down their weapons and kneeling in surrender, and saw Emperor Jianwen's imperial city becoming an isolated island in the night.

Flames soared into the sky above the imperial city. It wasn't the Yan army that set the fire—it was Jianwen himself. He stood on the stone steps before the Hall of Supreme Harmony, watching the flames rise from the northeast corner of the city, his face flickering in the firelight. Only a few eunuchs and Fang Xiaoru remained by his side; Fang Xiaoru was still speaking, but he could no longer hear what he was saying. He placed the imperial seal on the steps and turned to walk into the flames. No one knew where he went. Some said he perished in the fire, some said he escaped through a tunnel, some said he became a monk in a temple in the south. The Yan army searched every palace in the imperial city but found no trace of his body. They only found the imperial seal—placed upright on the stone steps before the Hall of Supreme Harmony, the firelight illuminating the inscription: "By the Mandate of Heaven, May Your Reign Be Everlasting."

July 20th. Zhu Di entered the Fengtian Hall. He wasn't wearing his dragon robe; he was still wearing the black satin overcoat he'd worn from Beiping to Nanjing, the cuffs frayed, and mud splattered from crossing the river still clung to his shoulder armor. He stood in the empty center of the hall, looking up at the throne for a long time. Zhu Neng stood behind him, Chen Mao beside him. Shen Du stood on the stone steps outside the hall, not going in. He leaned his sword against the steps for support, reaching into his robes to pull out the Southern Army's command flag—the one torn from Baojia Camp. The flag was covered in engravings: Dezhou, Jinan, Dongchang, Jiahe, Gaocheng, Qimeishan, Lingbi, Yangzhou, Nanjing. Each engraving represented a city, each engraving represented someone on the list of the dead. He folded the flag neatly and tucked it back into his robes, turning around with his sword, looking at the rising sun outside the hall. The fires in the city had been extinguished. From Baigou River to Nanjing, he and his soldiers traveled tens of thousands of miles, fought dozens of battles, large and small, and finally reached their destination. The black flags of the Yan army on Jinchuan Gate fluttered in the morning breeze.