Hsuang saw that he would have to be direct. "Please forgive an old man's superstitions," he said, inclining his head to Tzu Cheng. "I have never seen this thunder-powder used in battle. Lofting it over our own pengs makes me nervous."

Cheng's face betrayed his disappointment. "Of course, I understand your concerns, Tzu Hsuang, but I assure you that my artillerists will not make a mistake."

Another noble said, "I have seen this thunder-powder in action. It does little but rumble the ground and create a lot of smoke—"

"You have not seen it used properly, Nan Wang!" Cheng objected.

Wang bowed to Cheng. "Please forgive me, Tzu Cheng," he said. "I did not finish what I meant to say."

"Which was?" Hsuang asked, raising an eyebrow.

"It strikes me that against charging horses, rumbling ground and thick smoke might be more effective than arrows and flaming pitch," the nan finished. He looked toward the fields below.

"If I may speak," offered another minor lord, this one a middle-aged nan from Wak'an. "My own troops also use thunder-powder, though not for bombs."

"And how do you use this marvelous black sand?" Hsuang asked, turning to face the noble. He had noted earlier that each of this lord's pengs carried a large, funnel-shaped kettle, the function of which Hsuang had not been able to guess.

"Rockets, my lord," the nan responded. "We pack our kettles with gunpowder and arrows. Place us in front of the lines. When we light our weapons, our arrows will cut the enemy down like a sickle at harvest time."

Hsuang looked doubtful.

"What do we have to lose, Tzu Hsuang?" asked the nan. "From all accounts, normal arrows will not stop these barbarians."

"Let us use our thunder-powder," Cheng added, "and I promise we will chase the barbarian horses from the field."

As Hsuang considered the suggestion, he saw the cavalry assigned to scouting duty cross the bridge and ride toward Shihfang. The young noble commanding them had wasted little time doing as ordered, but Hsuang was still impatient for the riders to reach their positions. Until the first scouts reported, he was simply guessing at the barbarian intentions and hoping his son-in-law had judged the Tuigan accurately.

Fortunately, Batu's plan was simple and did not call for an astounding victory on Hsuang's part. In fact, the General of the Northern Marches expected Hsuang and the nobles to be defeated. Considering those expectations, it just might make sense to do as Cheng recommended and experiment with the thunder-powder. If Batu's plan did not work, a new weapon might prove just the advantage the Shou needed to destroy the Tuigan. A battle that the Shou were supposed to lose anyway would be the ideal place to conduct such an experiment.

"Very well, we'll try this thunder-powder," Hsuang said, looking at Cheng. "But not at the expense of tested tactics. Confine the catapults to a line of a hundred yards. If we lose this battle, we will need to retreat past them, and I don't want inadvertent fires or explosions impeding our men." Hsuang turned to the nan whose pengs carried the bronze kettles. "Your rockets must be separated from the rest of the line. I don't want our secret weapon to route our own troops."

The two nobles smiled broadly and bowed to Hsuang.

With the refugees from Shihfang still fleeing down the road, the battle preparations took until late afternoon. Hsuang put each lord's army where its peculiar composition would be best utilized. In front of the bridge, he placed two thousand seasoned troops from the southern provinces. Three of the noble armies were composed entirely of archers. These he placed at the base of the bluff, where they would be able to fire over the infantry.

The bulk of the armies he arranged in two ranks, one behind barricades on the far side of the brook, and the other behind similar barricades on the close side. His plan was simple: meet the barbarian charge with the first rank. After the enemy broke the line, the second rank would open fire as the barbarians crossed the brook—covering the rest of the army's retreat.

He protected the flanks with pikemen, who could meet and resist an unexpected charge from the sides. The rocketeers he interspersed along the first rank. He even had Tzu Cheng lay several thunder bombs on the bridge, so that it could be destroyed rapidly when the need arose.

By late afternoon, the refugees were gone. Hsuang's armies were in position and prepared for battle. The foragers that the noble had sent into Shihfang earlier started back, bringing with them five tons of dried grain. Pillars of smoke began rising out of the town.

Still, the scouts did not return, and there was no sign of the enemy. Hsuang began to think he had made a mistake, that the barbarians were even now circling around to cut off the Twenty-Five Armies. As the foragers crossed the wide valley below, they paused to set fire to the barley fields.

By early dusk, the fires in the fields had died, leaving only a thick curtain of smoke that hid the opposite side of the valley. Hsuang feared his army would spend the night in the entrenchments.

Finally, horse whinnies began sounding from the opposite side of the smoky dale.

"Are they our scouts?" Hsuang asked of no one in particular. "I can't see anything in this smoke."

A gentle rumble rolled across the burning fields, as if several hundred horses were galloping down the road from Shihfang.

"It can't be the scouts," said one of the nobles. "They wouldn't return all at once."

"It isn't the barbarians," Cheng countered. "There aren't enough of them."

No one took their eyes off the haze-filled valley.

A moment later, a wide line of riders broke out of the smoke and charged toward the brook. Their mounts were small and slender, with graceful forms and fine features. On their chests and flanks, the horses were protected by barding of hardened leather. The men wore long leather hauberks, split front and rear so they could sit in their saddles. Steel skullcaps, shaped in the fashion of a cone and trimmed with fur, protected their heads. Each man carried a short lance and a melon-sized cotton bag. In the fading light, Hsuang could not see the rider's faces, but he did not doubt they had flat noses and broad cheekbones similar to those of his son-in-law.

On the slope below, archers began nocking arrows. Officers looked toward the hilltop expectantly. Hsuang started to give the order to fire, but thought better of it. There were no more than two hundred barbarians. If he attacked, fifty times that number of men would fire. Thousands of arrows would be wasted.

Instead, he remained impassive as the enemy's small line approached. Every archer in the Twenty-five Armies remained stoic and silent, ready to pull his bowstring taut, resisting the temptation to loose an arrow before receiving the order.

Twenty yards on the other side of Hsuang's fortifications, the horsemen hurled the two hundred bags at the Shou line, then wheeled their horses around. The sacks landed among the defenders with dull plops. Small gaps opened in the lines as soldiers, fearing secret weapons or powerful war magic, scurried away from the mysterious bags.

Nothing happened. The riders rode away, disappearing into the smoking fields as if they were phantoms. The bags continued to lie where they had fallen. Eventually, a few soldiers ventured to open the sacks. Some simply stared at the contents in shock, while others closed the bags and looked away in disgust.

The lines began to rustle with murmurs of fear and anger.

"What can be inside those bags?" asked Cheng, frowning at the scene below.

"We shall see soon enough," Hsuang replied, motioning to his aide to fetch a sack.

When the boy returned, his face was pale and distressed. He carried a grimy hemp sack that held something the size of a melon. The youth bowed and presented the bag to his commander.