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

In the darkest hour before dawn, Zhao Laoliu squatted beside the campfire at the pass, shoveling ash with a stick. The fire had burned for most of the night, the ash thick and the flames had dwindled, leaving only dark red embers flickering in the night wind. He dipped his pipe into the ash to light it, took a deep drag, and the smoke billowed from his nostrils, scattered by the wind. He had never kept watch in his life, but tonight he had to. The banners at the pass fluttered in the wind, and the oil lamps in the tents were still lit, appearing no different from usual from a distance. But the tents were empty. Apart from him and a few auxiliary soldiers who had stayed behind to add firewood, there was no one else at the pass.

He Fu's scouts reached the foot of the pass at the crack of dawn. Two Southern Army scouts dressed in black emerged from the pine forest and lay prone in the bushes opposite the stream, peering over the pass for a long time. They saw campfires, banners, lights shining from the tents, and even a few figures moving around the fire. But what they didn't see was that there were only a handful of figures, and the same person moved back and forth between the campfire and the tents three times. He Fu's scouts returned and reported that everything at the Yan army pass was normal; the campfires were still burning, the banners were still in place, and the troop strength had not decreased. He Fu believed them. He was never one to take risks.

Shen Du stood atop the highest rock in the pass, his left hand gripping the hilt of his sword, his right hand resting on the rock. Dew soaked his armor, and the red tassel on his helmet clung to the top of the helmet in the night wind. He stared at He Fu's lantern on the main peak of Qimei Mountain, occasionally glancing down at the dark valley below the pass. Huo Zhen had just returned with his mounted archers; their horses' manes were matted with sweat, and they were panting heavily by the campfire.

"No movement." Huo Zhen tucked the dagger into his belt. "He Fu's messenger hasn't come out of the mountains."

"Wait a little longer," Shen Du said.

On the north bank of the Huai River, Zhu Di's army crossed in full before dawn. As the last rearguard cavalry crossed the pontoon bridge, the sky began to turn gray. Zhu Neng stood at the north bank ferry, personally overseeing the engineers cutting the ropes of the pontoon bridge. The cargo ships and the wreckage of the pontoon bridge drifted downstream, swirling eastward in the morning light. The wounded and sick were housed in the supply wagons that had crossed first. Zhu Neng had already dispatched messengers to Xuzhou to requisition provisions and medicine. From the Huai River to Xuzhou, a light cavalry force could reach the destination in a day.

Zhu Di stood on a small earthen slope on the north bank, turning back to look south. The morning mist had not yet dissipated, and the south bank of the Huai River was shrouded in a grayish-white fog, obscuring the outline of Mount Qimei. He reached into his robes and touched the silver token—the one Zhu Neng had given him, which he had then given to Li Jingzhong, and which Li Jingzhong had returned to him outside the Qianjin Gate. He clutched the token in his hand, turned around, and uttered two words to the messenger.

"Release the arrows."

Three rockets rose into the sky from the north bank. The gunpowder cartridges attached to their arrowheads exploded in the morning air, bursting into three balls of crimson sparks that lingered for a couple of breaths against the hazy sky before slowly plummeting to the ground. The flames were bright enough to be seen across the Huai River. Zhu Di watched the three balls of sparks fall into the river, his lips moving as if he were saying something, but no one heard him.

The Qimei Mountain Pass. Shen Du saw it.

As three sparks lit up the northern horizon, he stood on a rock, leaning on his sword. His left leg was numb—not from pain, but from standing. He had barely changed position since midnight; dew dripped from his armor, soaking his boots. He saw the three sparks bloom and fall in the northern morning sky, their red light illuminating half the heavens, clearer than any banner or command drum.

"Retreat." He pulled his knife out of the crevice and turned to everyone behind him, saying, "Everyone, retreat from the pass immediately and head north. Don't stop."

Zhao Laoliu kicked away the last embers of the campfire, sparks splattering and burning a few small holes in his trousers, but he didn't brush them off. He tucked his pipe into his coat and turned to follow Shen Du northward. He didn't look back. He dared not look back. He was afraid that if he turned back, he would see He Fu's flag on the main peak of Qimei Mountain pressing towards the pass, afraid that if he turned back, he would see countless dark figures emerging from the pine forest.

Huo Zhen led the mounted archers to cover the rear. Everyone mounted their horses, heads facing north, bows hanging from the saddles, quivers still full of arrows—they had ridden through the valley all night without firing a single shot. Shen Du, leaning on his sword, brought up the rear. His left leg ached with every step, and his pace was almost half as slow as usual, but his direction remained perfectly correct. After reaching safety north of the pass, Huo Zhen left several spare horses. When he climbed onto his horse, his left leg was completely useless; Zhao Laoliu helped him from behind, and he managed to mount as well. The group galloped north along the valley, crossing the pine forest they had repeatedly traversed on the northern slopes of Qimei Mountain, when the distant bugle calls of the Southern army echoed behind them.

He Fu finally discovered it. But it was too late.

A few days later, the Yan army retreated north to Xuzhou. The army rested for several days outside Xuzhou, replenishing its supplies, caring for the wounded, and reorganizing the remaining troops. Although the retreat from Qimei Mountain did not result in a rout due to pursuit by the Southern army, the cost of traveling a thousand miles south and then retreating was substantial—they had carried enough rations to support a lightly armed assault when they left Dezhou, but on the return journey, more soldiers succumbed to hunger and disease than died in battle. Zhu Di did not allow this retreat to turn into a rout, but he could not ignore the fact that his first attempt to bypass the fortified cities and directly attack the capital had failed.

In the Xuzhou government office, Zhu Di convened a military council. This wasn't the military meeting held during the southward campaign, but a debriefing. He laid out the military reports from every battle from Dezhou to Qimei Mountain on the table, summoned all the generals, and without assigning blame or issuing anger, simply asked each person to explain the problems they had encountered. Why were the supplies insufficient? Why did the terrain of Southern Zhili completely hinder the cavalry's deployment? Could He Fu's anesthetic crossbows have been detected in advance? Could Mei Yin's scorched-earth policy have been countered beforehand? One question after another was laid out on the table; some answered, some remained silent, and some filled bamboo slips with notes. Shen Du sat in a corner, a map of the terrain south of Qimei Mountain that he had drawn himself resting on his lap. His left leg had finally been properly bandaged by the military doctor, treated with herbal medicine, and the swelling had subsided somewhat, but he still walked with a limp. His centurion's unit, which had set out from Dezhou with nearly eighty men, returned to Xuzhou with fewer than thirty able-bodied men, several of whom were wounded veterans returning with injuries. Zhao Laoliu's left arm, where he had been grazed by the anesthetic crossbow bolt, had scabbed over, but his left hand was still somewhat clumsy. He sat with a pipe in his mouth, sharpening his short-handled axe in circles on a whetstone with his right hand. Gu Zhang's bandage on his left arm hadn't been removed since it tore open on the night of the siege. The army doctor said that if he didn't rest, his arm would be useless. He listened without a word and led his troops in training as usual the next day. Zheng Biao had acquired his fourth sword since the southward campaign, a sword he had seized from a Southern Army captain at the foot of Lingbi City. Two characters were engraved on the hilt—"Zhenhuai." He held the sword up and looked at it for a long time before sheathing it.

From Xuzhou northwards, the Yan army retreated back to Beiping. Zhu Di stood atop the city wall of Beiping, gazing at the southern sky, silent for a long time. Behind him, Zhu Neng's right arm was finally forcibly slinged to his chest by the army doctor. Chen Mao squatted at the foot of the city wall, sharpening his knife, the torchlight flickering on the blade. Huo Zhen fished another horse bone from the pot, using a dagger to shave off the tendons. They had all heard the same news—Jianwen had recalled Xu Huizu to Nanjing and sent Sheng Yong to retake control of the Huai River defense line. This southward advance had breached Hebei, swept through Shandong, and reached the Yangtze River, but failed to cross. Next time, however, they would not retreat.