Transmigrated into Li Chengqian, he effortlessly ascended the throne and became emperor.

However, just as Li Shimin had predicted, Anshi City was indeed an extremely tough nut to crack.

For the next several dozen days and nights, the sky over Liaodong seemed to be soaked in blood, and the rumbling war drums, like the roar of an ancient beast, echoed endlessly over the wilderness outside Anshi City.

However, Anshi City's terrain is too treacherous.

This city is like a steel hedgehog perched on a cliff, and its lord is a ruthless character who is well-versed in military strategy and extremely resilient.

Faced with the Tang army's fierce and relentless attacks, the defending troops defended themselves flawlessly.

Logs and stones rained down from the city walls, and molten metal mixed with smoke from the siege towers, turning the Tang army's siege ladders into charred remains time and time again.

During the most intense days, the Tang Dynasty and Anshi forces engaged in six or seven rounds of fierce fighting every day.

At dawn, the Tang army's battle flags had just been planted on the city wall when, at noon, the defending troops launched a desperate counterattack and cut them down.

At dusk, the Tang army's vanguard soldiers once again risked their lives to fill the trenches, but were forced back by a sudden barrage of arrows fired from within the city after nightfall.

Human life, beneath this city, has become the cheapest consumable.

Despite the bravery and skill of the Tang soldiers, they were unable to achieve a decisive breakthrough in this intense tug-of-war, and the battle situation became a stalemate.

……

Half a month later, outside Anshi City, on a high slope only a few miles from the front line.

Li Shimin, dressed in dark gold armor and riding the steed Tiele Piao, gazed with a furrowed brow at the distant, smoke-filled city walls, a hint of anxiety appearing in his eyes for the first time.

"Your Majesty, our fifth attack today has been repelled again." Li Shiji arrived on horseback, covered in dust and filled with resentment. "That Anshi City Lord is simply insane! He repaired the breached walls overnight with wooden palisades. The defenders' resilience is beyond imagination!"

Li Shimin didn't speak, but gripped the reins tightly until his knuckles turned white.

Today, Li Chengqian also came along. Upon hearing Li Shiji's words, he sighed.

It wasn't that the Tang army was cowardly, nor that the generals were incompetent; rather, there was a layer of paper obscuring the truth due to the limitations of the era, which no one had yet dared to pierce.

"Father, Duke of Ying, look at those soldiers who have just withdrawn."

Li Chengqian raised his hand, which was adorned with a white jade thumb ring, and pointed into the distance.

Li Shimin and Li Shiji looked in the direction he pointed.

Many of the retreating infantrymen and archers collapsed to the ground, sprawled out, without even tending to their wounds.

Even more strangely, almost all the archers were painfully rubbing the back of their necks and sore arms, and some even had their hands holding knives convulsing and trembling uncontrollably.

"This is..." Li Shiji, a seasoned military commander, keenly sensed something amiss. "After several days of continuous sieges, fatigue is common among the soldiers, but why are the archers so severely exhausted?"

Li Chengqian sighed: "It must be because of the terrain."

"Anshi City was built against the mountain, and the terrain where the city was located was already higher than the surrounding open fields. In addition, the city walls were extremely high. All of our army's attacks were essentially extremely difficult uphill assaults."

Li Chengqian walked to the edge of the battle formation, casually pulled a powerful bow from the weapon rack, and personally demonstrated the posture of drawing a bow and shooting an arrow to the two men.

"In ordinary flat terrain warfare, soldiers can fire horizontally with a wide field of vision and smooth arm strength. However, in order to shoot arrows onto the city walls of Anshi, all archers must raise their eyes significantly and maintain an extremely awkward head-tilting posture for a long time. This leads to two fatal problems."

Li Shimin's pupils contracted sharply; his exceptional military acumen allowed him to instantly grasp the key point: "Accuracy and stamina!"

"Your Majesty is wise," Li Chengqian flattered Li Shimin, "The prolonged upward gaze puts several times the normal pressure on the soldiers' necks and arms. Missing shots is secondary; the more fatal problem is that this posture, defying human physiology, is draining the stamina of our Tang warriors at an alarming rate. After six or seven rounds a day, the soldiers can't even fully draw their bowstrings. How can they possibly suppress the rested enemy troops on the city walls?"

A word to wake up the dreamer!

Li Shiji gasped, then slapped his thigh. "Your Highness is wise, your words hit the nail on the head! This old minister has been wondering why our army's suppressive firepower weakened in the later stages. I thought it was due to the enemy's tenacity, but now I see the crux of the matter lies here! A frontal assault is a cardinal sin in military strategy!"

"It wasn't just the archers; the siege infantry, too, felt amplified by the sheer height of the walls as they climbed the ladders. Morale was gradually eroded by this daily struggle to look up at the towering walls."

Li Chengqian tossed the powerful bow back onto the shelf, lightly dusted off his hands, and then coughed softly, covering his mouth.

But then, Li Shimin's brows furrowed into a deep knot: "The crux of the problem has been found, but Anshi City is ultimately situated on a precipice; we can't simply flatten the city and attack it. Since we can't attack uphill, what else can we do?"

Li Shiji stroked his beard, a ruthless glint in his eyes, and said in a deep voice, "Your Majesty, since the city wall is too high, our army will build an even higher mountain ourselves! This old minister proposes that it be built in the southeast corner of Anshi City, with work day and night to pile up earth and stones, constructing an earthen mountain even higher than the city wall! Once the mountain is completed, our army will be able to command a superior position, instantly turning the disadvantage of an uphill attack into a decisive annihilation from below!"

Upon hearing this, Li Chengqian's eyelids twitched slightly.

The course of history has reached a perfect conclusion here.

Historical records indicate that the Tang army spent two months working day and night to build a mound of earth that could overlook Anshi City.

But on the very day that the earthen mound was about to be completed and the final assault was about to begin, torrential rains fell in Liaodong, making the soil and rocks soft. Combined with the sheer size of the mound, it collapsed with a deafening roar.

The collapsed earthen mound not only killed countless Tang soldiers, but also coincidentally collapsed part of the city wall of Anshi.

As a result, the garrison of Anshi City took advantage of the chaos to break out and seize the earthen mound ruins that the Tang army had painstakingly built up over two months, turning it into a strong fortress to defend against the Tang Dynasty.

Li Shimin was furious and executed Fu Fu'ai, the general in charge of supervising the construction of the earthen mound. However, he still could not reverse the defeat. In the end, due to the approaching winter and the depletion of food supplies, he had no choice but to withdraw his troops with regret.

This history was a regret for Li Shimin in his later years. Now that Li Chengqian had come, he would never allow such a ridiculous tragedy to repeat itself.

"Duke of England's plan is brilliant, a truly ingenious strategy to cut off the enemy's supply lines!" Li Shimin clapped his hands and laughed, then decisively ordered, "Issue my decree to mobilize all military laborers and begin immediately..."

"Father, please wait."

Li Chengqian suddenly interrupted.

"Gao Ming, what are your concerns?"

Li Shimin now listens to his son's every word and immediately stopped issuing the decree.

Li Chengqian did not answer directly, but walked to the side and gently kicked the soil unique to Liaodong with the tip of his boot.

"In July and August, the climate in Liaodong is unpredictable, with frequent torrential rains. The earthen mound that the Duke of Yingguo wanted to build had to be several meters higher than the city wall, so you can imagine how enormous it was. But if it was just made of mud and rubble, it would ultimately be a tree without roots."

"May I ask, Your Excellency, if a mound of earth were piled up to several meters high, and suddenly it were hit by days of torrential rain, causing the earth and rocks to absorb water and become loose, and the army were frequently moving around on the mountain, what would happen if the mound could not bear the weight and collapsed?"

Upon hearing this, Li Shiji's smile froze instantly, and cold sweat instantly soaked his back.

He's a commander who's fought so many battles, how could he not understand the risks involved?

However, in their eagerness to conquer the city, they momentarily overlooked this fatal hidden danger.

If the earthen mound were to collapse at a critical moment, it would be nothing short of a catastrophe for the Tang army formation that was so close at hand!

"Your Highness is absolutely right! This old minister almost made a fatal mistake!" Li Shiji knelt down with a thud, his voice trembling with lingering fear. "But if we don't use the earthen mound strategy, are we really going to be worn down and die here?"

Li Shimin's face also darkened.

Just when you see a glimmer of hope to break the deadlock, it's ruthlessly extinguished by a bucket of cold water. This feeling is truly maddening.

"Father, do not worry. Now that I have seen the hidden danger, I naturally have a way to resolve it."

Seeing that the time was right, Li Chengqian began his performance.

"Father, have you forgotten? We have cement."

"We used giant timber as the framework, filled the inside with earth and stones, and poured the outside with cement mixed with sand and gravel. In less than three days, once the cement dried, this earthen hill would no longer be a pile of loose sand, but a complete fortress. In addition, we only built the steps on the sunny side, so the people from Anshi on the other side could not climb up from thin air no matter what."

"In this way, even if there is a continuous downpour, or even if the city lord of Anshi brings ten elephants to ram the mountain, this mountain will not collapse in the slightest."

Li Shimin looked at Li Chengqian, then suddenly burst into laughter, his laughter filled with an unprecedented sense of relief.

"Issue my decree! Immediately summon all nearby cement to Anshi!"