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

Even after the siege was lifted, the air outside Chang'an still reeked of burning and blood. On the ruins of the Qiang camp, charred tent frames lay crookedly stuck in the frozen earth, creaking in the wind. The remains of a battering ram lay embedded in the mudflats south of the Wei River, its iron head half-submerged in icy water, the hemp ropes still entangled with broken arrows shot from the city walls. The corpses piled up at the base of the walls for two months began to rot; despite the winter, the cloying, stench of decay that blew in from outside the city made one instinctively cover their nose and mouth with their sleeve.

The work of clearing the ruins began at dawn. Old Wei led a squad of infantrymen who could still walk out of the city gate, covering their mouths and noses with rags, and dragged the corpses one by one from the base of the city wall to an open area on the north bank of the Wei River for burial. The bodies of the Qiang people were mixed with those of the Qin soldiers; the frozen armor plates were pried open to reveal the pale skin beneath, and some of the corpses' fingers were still in the grip of a knife, impossible to pry open. Old Wei squatted silently beside the body of a Qin infantryman for a long time. It was someone he knew—one of the routed soldiers who had marched back from the Fei River, who had been shot through the throat by a stray arrow on the day of the fiercest defense of the city. Old Wei took off his helmet, tucked it under his arm, and then personally buried him on the slope at the foot of Mount Li, building a small grave with rubble.

No one spoke. Everyone worked in silence. Occasionally, someone would stop to wipe the sweat or tears from their face with their sleeve, then continue dragging the body with their head down.

Shen Du stood guard on the north gate tower. The Xianbei envoy had arrived the previous evening and was accommodated in a temporary post station in the north of the city. Murong Chui made a show of it—the envoy carried no weapons, was respectful, and spoke politely, but every word was a test. He said that General Murong was willing to send troops to assist in the defense of Chang'an, as long as the court provided provisions and pay; he also said that the Xianbei cavalry could help the Qin army wipe out the remnants of Yao Chang's forces north of the Wei River, provided the court granted Murong Chui the authority to command the armies of Hebei. After hearing this last night, Shen Du did not immediately reply, but simply had someone bring the envoy a bowl of millet porridge—so thin that one could see their reflection in it. When he brought it to the envoy, he deliberately said, "The daily ration for the garrison in Chang'an is just this bowl of porridge. Please help yourself." The envoy looked at the bowl of porridge for a long time, then silently picked it up and drank it, without urging Shen Du to reply.

Shen Du stood on the city wall, holding a bowl of the same thin porridge in his hand. He stirred it with his chopsticks, looking at the sparse grains of rice in the bowl. The siege was over, but the food problem was not solved. The supply lines outside the city had not been fully restored. Murong Chui's men were watching the city from the outside. Although Yao Chang had retreated, his main force was still in Weibei and could return at any time.

Lieutenant Zhu walked over from behind the north gate's battlements, his armor still covered in mud from clearing the ruins. He stood beside Shen Du, looking at the Xianbei camp outside the city, and suddenly said, "Master Shen, I think the Xianbei are more difficult to deal with than the Qiang. At least the Qiang fight openly, while the Xianbei talk to you with a smile, but their hands are always on the hilts of their swords."

"Murong Chui is waiting for us to starve to death." Shen Du finished his porridge and placed the bowl on the crenellation. "He won't attack the city proactively. Attacking a city means people will die, and if too many people die, his foundation in Hebei will become unstable. He also won't withdraw his troops proactively, because withdrawing means giving up the lucrative Guanzhong region. His ideal outcome is for us to starve to death in the city, or for Fu Jian to die, and then he can enter the city under the pretext of 'serving the emperor' and take over everything. He's waiting now—waiting for the day we can't hold on any longer."

Commander Zhu was silent for a moment, then lowered his voice and asked a question he had probably been thinking about for a long time: "How much longer can His Majesty hold out? I'm not asking about supplies—I'm asking about manpower. His Majesty's temper has become increasingly erratic these days; he gets angry and yells at people at the drop of a hat. I haven't told anyone about this before. But I think you should know."

Shen Du didn't answer. He looked at the Xianbei camp outside the city, his mind preoccupied with something else—last night, when he went to the palace to report on the city's defenses, Fu Jian had asked him a question. He was standing in the hall reporting the casualties of the city's defense forces when Fu Jian suddenly interrupted him, saying, "I know you had Zhou Jing replace all the guards in the palace with defeated soldiers returning from the Fei River." Shen Du said those guards had no connection to Yao Chang. Fu Jian didn't speak, remaining silent for a long time before suddenly saying out of the blue, "My crown prince is still in Chang'an." Shen Du looked up at him. Fu Jian's gaze didn't seem like that of an emperor discussing his heir; it was more like that of a father discussing his last surviving child. Shen Du said that Chang'an's defenses were secure, and the crown prince was safe. Fu Jian didn't reply, but simply waved for him to leave. As Shen Du reached the palace gate, Fu Jian suddenly said again, "General Li, I shouldn't have placed Zhu Xu at the rear of the battle line back then at Feishui. You came back from Feishui—you know better than I do that my biggest mistake in life wasn't trusting the wrong person, but using the wrong person."

Zhu Xu shouted "The Qin army has been defeated!" from behind the Qin army lines—an incident that Fu Jian had been repeatedly agonizing over ever since the rout. Zhu Xu was a surrendered general from the Eastern Jin Dynasty, and Fu Jian had originally intended to use him to supervise the army from behind the lines, but unexpectedly, he became the trigger for the complete collapse. The fact that Fu Jian brought this up again shows that he not only regretted his actions but had also begun to distrust all those around him who were not his direct subordinates. He replaced the palace guards with defeated soldiers returning from the Fei River, ostensibly trusting them, but in reality, only trusting them. But this trust was fragile; someone repeatedly struck down in dire straits can easily slide from excessive trust to excessive suspicion. Shen Du approached Fu Jian, bowed, and lowered his voice, saying, "Your Majesty, on my way back from the Fei River, while gathering the fleeing soldiers along the way, I discovered something—although the fleeing soldiers from various tribes are escaping, they are fleeing in different directions, and their hearts are also different. Some want to go home, some want to pledge allegiance to the new ruler, and some just want to survive. But as long as these people can be kept in check, the war can still be fought. Now, the Xianbei outside the city and the Qiang people who have retreated to the north of the Wei River are facing the same problem. They are numerous, but their hearts are even more scattered. I implore Your Majesty to take care of your health and trust those who are still standing on the walls of Chang'an."

Fu Jian looked at Shen Du, remained silent for a long time, then picked up a token from the imperial desk and placed it on the edge of the desk. His voice was hoarse and tired, but every word was clearly enunciated: "Take this token—it's not for mobilizing the guards, it's for mobilizing the Crown Prince's Eastern Palace guards. Crown Prince Fu Shen's guards number twelve hundred, all imperial guards, which I've kept without using. Now I'm giving it to you. You will guard Chang'an for me. And you will guard the Crown Prince for me." Shen Du accepted the token with both hands, knelt down and kowtowed. Then he stood up and retreated step by step from the side hall.

Shen Du stood atop the city wall, clutching the Crown Prince's guard token in his hand. Commandant Zhu stood beside him, waiting for his answer to the question about Fu Jian. Shen Du finally turned and said, "His Majesty is more lucid than he was two months ago. He knows who is helping him and who is waiting for him to die. That's enough for us." He tucked the token into his robes.

After descending from the city wall, Shen Du went directly to the wounded soldiers' camp. The camp was filled with a bitter, pungent odor of herbs mixed with pus and blood. Zhou Jing was squatting in a corner, changing the bandages of a wounded soldier. His fingers weren't as nimble as they used to be; he had to pause after each bend before continuing, but his bandaging was incredibly steady, each bandage neat and secure. Seeing Shen Du, he wiped the sweat from his brow with the back of his hand, stood up, and said that seven more wounded soldiers were able to walk on their own with crutches today, and after a few more days of rest, they would be able to climb back onto the city wall.

Shen Du took the bamboo slips out of his robes and handed them to him. He had read the records of tribal conflicts on the bamboo slips countless times, but now he didn't need to read them anymore—what he needed was to turn this material into a network. Zhou Jing took the bamboo slips, flipped through a few pages, and looked up to ask him what he wanted to do. Shen Du said, "The old grudges and conflicts between the Xianbei, Qiang, and Xiongnu tribes are all recorded on the bamboo slips. Before, we were the ones who distrusted each other; now it's time to make the enemy distrust themselves. Yao Chang is reorganizing his remnants in Weibei. The Qiang tribes under his command are not a monolithic entity—there are factions within the Qiang people, and some tribal leaders have been forcibly coerced by him. If these people knew that Yao Chang planned to sacrifice his pawns to save his king after the defeat and shift the blame onto them, what would they do?" The same applies to Murong Chui's side—although the Xianbei tribes under his command obey his orders, Murong Chui's younger brother, Murong De, has a long-standing grudge against him. If the real reason why Murong Chui is holding back his troops outside Chang'an is revealed, some people within the Xianbei community will also question him.

Zhou Jing listened in silence for a long time, then suddenly laughed. The laugh on his wrinkled face was complex—not happiness, but shock. "This is an open conspiracy. You hand someone else's knife to their neighbor, and they'll start arguing themselves; we don't even need to hand them a second knife." He put the bamboo slips into his robes, stood up, and walked out. He paused at the door, turned back to Shen Du, and said, "I walked from Feishui to Chang'an, never expecting to end up not as a military doctor, but as a spy chief." Shen Du said he wasn't a spy chief—just a knife sharpener. The knives were carried by the tribes themselves; all he had to do was tell them which way the hilts faced. After Zhou Jing left, Shen Du stood alone in the courtyard of the wounded soldiers' camp for a while. Chang'an was still there, Fu Jian was still there, and those who had followed him from Feishui back to Chang'an were still there. But they were all thinner, more tired, and more deeply wounded. The cracks in the city walls had been patched and reopened, and the iron hoops on the heavy gates had been reinforced again and again. The city is like a person covered in bandages still standing on the battlefield, not yet drained of blood, but almost completely exhausted.

He went up to the west gate tower to inspect the reinforcement of the crenellations. Commander Zhu was leading a squad of infantry carrying the last batch of broken bricks and stones up the tower, rearranging the siege stones. Shen Du stood beside him for a while, then suddenly said, "Tonight, have the kitchen cook an extra pot of porridge." Commander Zhu was taken aback—an extra pot of porridge meant fewer days' worth of provisions. Shen Du turned to look at him. "It's not for the garrison. It's for the Xianbei envoys. Cook the porridge thicker, put it in open basins, let the Xianbei envoys see it with their own eyes—say that Chang'an has ample provisions and the garrison's morale is high. They'll go back and tell Murong Chui that the city isn't in a hurry to surrender."

Commander Zhu was silent for a moment, then nodded vigorously. Shen Du stood on the city wall, watching the rising smoke at the foot of Mount Li in the distance—the smoke from the garrison burning and clearing away corpses and debris. The grayish-white column of smoke drifted obliquely northward in the morning breeze, across the Wei River, and all the way to the direction of the Xianbei camp. He still had something in his hand—a short knife, its hilt tied with a red knot woven by Azhi. He held the knife in his hand for a long time, then sheathed it and turned to walk down from the city wall.