Chapter 80: The Entire Army Halts Its Assault

An Qingxu and Cui Qianyou devised their attack strategy as follows: while launching feigned assaults with several thousand men at the east and north gates, they would simultaneously mount a full-scale attack of ten thousand troops at the south gate in successive waves, maintaining an unbroken offensive against the ramparts of Tongguan.

As soon as the soldiers crossed the forbidden trench and climbed to the western edge in preparation to storm the walls, another force of ten thousand was ordered to transport stones, earth, and felled trees and bamboo, focusing their efforts on filling in the narrowest section of the forbidden trench outside the eastern face of the south gate, intending to level it and turn this natural barrier into a thoroughfare.

An Qingxu’s confidence in this bold maneuver stemmed from the fifteen thousand troops under his command, and the knowledge that his father, An Lushan, was approaching with nearly two hundred thousand men just two days’ march away. From the reconnaissance during the daytime assault, he surmised that there were at most just over ten thousand Tang soldiers inside the city, with little fighting spirit. If he pressed the attack through the night, exploiting the darkness that would hinder the defenders’ vision, it would grant his men the opportunity to fill the trench unimpeded, and thus, as they stormed the walls, they could also level a section of the trench. Once that was accomplished, a renewed, intensified assault would surely bring the fall of Tongguan.

As soon as An Qingxu’s orders were issued, the rebel assault commenced. The vanguard of ten thousand soldiers surged ceaselessly from the eastern edge of the forbidden trench, scrambling into its depths, scaling the western edge, then clambering up siege ladders to storm the walls. Meanwhile, those assigned to fill the trench set to work, using sacks of earth and stone and large sections of timber and bamboo to begin the filling.

However, as soon as the attack began, An Qingxu and Cui Qianyou, directing the operation, realized something was amiss.

The eastern edge of the forbidden trench lay about eighty paces—roughly one hundred and twenty meters—from the southern wall of Tongguan, well within the range of arrows shot from the ramparts and the beacon towers at the twelve-linked fortresses. Yang Xi, having anticipated that the rebels would attempt to fill the trench while storming the city, ordered waves of four thousand archers at a time to unleash volley after volley upon the attackers as soon as they began their assault on the trench.

Naturally, the giant crossbows atop the walls also began their relentless barrage.

After learning that the rebels planned a night assault, Yang Xi ordered the eight thousand men under Dou Hua and Zhang Jian—who had just enjoyed a brief rest and resupply—to reinforce the southern wall. This brought the defending force at the south gate to over sixteen thousand, doubling the original number, and thus doubling the number of archers firing in each wave. The stream of arrows from the walls grew even denser.

Each of the beacon towers at the twelve-linked fortresses also saw their garrisons increased to three hundred men apiece.

“General, the Tang archers on the walls are shooting in dense volleys—our casualties are heavy!” a panicked soldier tumbled before a colonel directing the assault, breathlessly reporting, “It seems Tang reinforcements have arrived—the walls are packed with troops!”

“I hear you. Go scout again!” the colonel, surnamed Wu, scowled and impatiently ordered the soldier to investigate further. As the man dashed off, he quickly relayed another message to a nearby aide: “Report to the Prince and Deputy Commander Cui at once—the Tang reinforcements have arrived; the arrow fire is fiercer than it was by day, and our losses are grave!”

“Yes, General!” The waiting soldier sped away to deliver this message to An Qingxu and Cui Qianyou, watching from the heights behind.

“What? Tang reinforcements have already reached Tongguan?” An Qingxu was taken aback by the report.

He had already sensed something odd from the unusual shouts and drumbeats coming from the walls, and had begun to suspect that more Tang troops had arrived. Now his suspicions were confirmed.

“Tang reinforcements really reached Tongguan?” Cui Qianyou was equally startled.

From the afternoon’s fighting, it hadn’t appeared that any new Tang troops had arrived, but now the situation was clearly different: the formations atop the walls had changed, the arrow volleys were denser, and the battle cries louder. Unless this was some ruse, an attempt to feign strength, the only explanation was that Tang reinforcements had indeed arrived.

Still, neither An Qingxu nor Cui Qianyou dared to be certain.

They dreaded this possibility. If a large Tang force had truly arrived, there would be no way to take the city; the forbidden trench would once again become an unassailable barrier, and even the most determined massed assault would never breach Tongguan’s ramparts.

Yet, uncertain, An Qingxu refrained from issuing new orders—the storming of the trench and the filling operation continued.

But under the withering volleys from the defenders, scores of attackers fell along the edge or in the depths of the trench. Those assigned to fill it were mown down in droves before they could even deposit their loads. Soon, the eastern edge of the trench was littered with corpses; countless wounded lay moaning and crying for help, only to be ignored or trampled by their comrades.

The number of rebels struck down along the trench was so great that it severely hampered the advance of those following behind.

Bodies and wounded tumbled into the trench in such numbers that sections previously cleared by the flood were once again choked with corpses.

The walls of Tongguan rose forty to fifty feet high—some thirteen or fourteen meters—and with the difference in terrain, they towered nearly seventy or eighty feet above the eastern edge of the trench, almost twenty meters. The beacon towers at the twelve-linked fortresses stood higher still, nearly thirty meters above the trench’s edge and over forty meters above the trench floor. Assaulting uphill, the rebels could barely shoot arrows to reach the walls, and only the strongest among them could hope to reach the highest towers. Those in the bottom of the trench could not even hope to shoot so high. In short, the rebels’ assault required them to charge through a hail of arrows, and their casualties far outstripped those of the defenders.

“Your Highness, the Tang arrows are so dense—we’ve already lost over two thousand men, but none have managed to cross the trench!”

This report heightened An Qingxu’s unease. He was now certain the Tang reinforcements had arrived. He also knew that with the defenders’ numbers swelled, there was no hope of achieving the night assault’s objectives. After a period of agonized reflection, he issued an order he himself could not judge as wise or foolish.

“Convey my order: the entire army is to cease its assault!”

In the pitch darkness, crossing the trench was an ordeal; even by day, with full light, caution was essential to avoid injury. At night, the danger was multiplied—many soldiers who had survived the arrows fell or were injured stumbling into the trench. With Tang reinforcements now defending the walls and arrow fire thick as rain, even the men carrying earth could not approach the edge.

Thus, to prevent further needless slaughter, An Qingxu had no choice but to call off the attack, ordering instead that small squads continue to harass the walls, and that the main assault wait until dawn.