The Xi Xia defenders could have no idea how many Mongols had crossed the desert against them. Though Genghis rode up to the edge of bow range with a dozen officers, he kept the main army well back in the twisting canyon. He had decided against sending climbers up the slopes. The plan depended on the defenders thinking of them as unsophisticated herdsmen. Watchers on the peaks would reveal at least some talent for planning and make the fort soldiers suspicious. Genghis chewed his lower lip as he stared up at the Xi Xia fort. Archers clustered like ants on the wall and at intervals one would send a shaft high into the air to get the range for any assault that might follow. Genghis watched the last of them sink into the ground a dozen paces ahead of him. His own men could fire further and he spat contemptuously in the enemy archers’ direction.

      The air was thick and still in the canyon where no winds could blow. The heat of the desert was still strong while the sun crossed overhead and cut their shadows almost to nothing. He touched the sword of his father for luck, then turned his pony and rode back to where a hundred warriors waited.

      They were silent, as he had ordered, but excitement was visible in their young faces. Like all Mongols, they relished the idea of tricking an enemy even more than overwhelming him by force.

      ‘The wooden shield is lashed together,’ Khasar said at his shoulder. ‘It’s rough, but it will get them to the foot of the wall. I have given them forge hammers to try the gate. Who knows, they might break in.’

      ‘If that happens, have another hundred ready to charge in support,’ Genghis said. He turned to Kachiun, standing nearby to oversee the last details. ‘Hold the rest back, Kachiun. It would be an easy killing ground for them to be packed in tight while only a few can climb through. I do not want them running wild.’

      ‘I’ll put Arslan at the head of the second group,’ Kachiun replied. It was a good choice and Genghis nodded assent. The swordsmith could follow orders in a storm of arrows.

      At their backs, the wall seemed to loom still, though it was lost to direct sight. Genghis had no idea what lay behind the dark stones, or how many men defended the pass. It did not matter. In less than two days, the last water skins would be empty. The tribes would start to drop after that, dying from thirst and his ambitions. The fort had to fall.

      Many of the men carried beautiful swords and spears to leave on the sand, anything that might catch the eye of the defenders and make them come out. To a man, they wore the best armour, copies of a Chin design. In the heat, the finger-width iron scales stung bare skin and their silk undertunics were soon sour with sweat. They gulped from skins of the dwindling water supply. Genghis had imposed no ration on men about to risk their lives.

      ‘We have done all we can, brother,’ Khasar said, interrupting his thoughts. Both men watched as Kokchu appeared among the warriors, scattering precious water over them and chanting. Many of the men bowed their heads to receive his blessing and Genghis frowned to himself. He imagined Temuge doing the same thing in the future and could find no glory in it.

      ‘I should be among the attackers,’ Genghis murmured.

      Kachiun heard and shook his head.

      ‘You cannot be seen to run from anything, brother. Perhaps the plan will go wrong and the tribes will be routed. You cannot be seen as a coward and not half the army knows the plan here, not yet. It is enough for them to see you watching. I have chosen most for nerve and courage. They will follow orders.’

      ‘They must,’ Genghis replied.

      His brothers moved apart to clear the trail for the assault group and the wide wooden shelter. The men bore it above their heads with pride and the tension built in silence.

      ‘I would see this wall brought down,’ Genghis said to them. ‘If not with blades and hammers, then with guile. Some of you will die, but the sky father loves the warrior spirit and you will be welcomed. You will open a way to the sweet kingdom beyond. Sound the drums and horns. Let them hear and worry in their precious fort. Let the sound carry right to the heart of the Xi Xia and even the Chin in their cities.’

      The warriors took deep breaths, readying themselves for the sprint to come. In the distance a bird called shrilly, high on the thermals above the hills. Kokchu exclaimed that it was a good omen and most of the men looked up to the blue bowl above their heads. A dozen drummers began to pound the rhythms of battle and the familiar sound lifted them all, making hearts beat faster. Genghis swept his arm down and the army roared and horns wailed. The first group jogged to the point where they could turn into the main canyon and then accelerated, calling a raucous challenge. Echoing back came the warning cries from the fort.

      ‘Now we will see,’ Genghis said, clenching and unclenching his sword hand.

      The voices of the warriors crashed against the sides of the pass as they ran. They were suffering under the weight of the barricade above their heads, already half blind with sweat. It proved its worth in moments as it bristled with black shafts, the coloured feathers quivering. The archers were well disciplined, Genghis saw, loosing together after a barked order. One or two shots were lucky and by the time the barricade reached the wall, there were three still figures lying face down on the sand in their wake.

      A dull booming filled the pass as the hammer men attacked the door in the wall. Archers swarmed above, leaning over to send their arrows straight down at the smallest gaps. Men cried out and fell away from the edges of the wooden shield, their bodies jerking as they were hit again and again.

      Genghis swore under his breath as he saw heavy stones being raised to the parapet. He had discussed the possibility with his generals, but still winced in anticipation as an officer wearing a plumed helmet raised his arm and screamed an order. The first stone seemed to fall for a long time and Genghis heard the crack as it drove those below to their knees. As they struggled up, the hammer men struck even harder, their blows coming as fast as the drummers they had left behind.

      Two more stones fell before the wooden barricade broke apart. The hammers were thrown to the sand and a great roar of panic went up as the archers above found fresh targets. Genghis clenched his fists as he watched his men scatter. The door in the wall had held and they could do nothing but shake their